A system and method for separating alkali metal ions by non-steady flow discrete extraction and stripping

Abstract

The present invention discloses a system and method for separating alkali metal ions by non-steady flow discrete extraction and stripping. The non-steady flow discrete extraction system includes a non-steady flow discrete extraction device, a periodic flow pump, a first intermediate liquid storage device, a first liquid replenishing device, a second liquid replenishing device, and a first collection device. The non-steady flow discrete stripping system includes a non-steady flow discrete stripping device, a periodic variable frequency pulse pump, a second intermediate liquid storage device, a third liquid replenishing device, a fourth liquid replenishing device, and a second collection device. The non-steady flow discrete extraction method includes allowing extractant oil droplets or hollow oil droplets encapsulating bubbles to float in a mixed aqueous solution of alkali metal ions and then aggregate to obtain a loaded organic phase; continuously collecting the obtained organic phase in batches; and stripping the organic phase. The non-steady flow discrete stripping method includes allowing stripping liquid droplets to sink in the alkali metal ion-loaded organic phase to obtain a stripping raffinate; and continuously collecting the obtained stripping raffinate in batches. Utilizing the difference in the extraction and stripping rates of the alkali metal ions, efficient mutual separation is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of extraction and separation of rare metals lithium, rubidium and cesium, and relates to a system and method for extracting and stripping and separating five alkali metal cations of lithium, sodium, potassium, rubidium and cesium, and in particular to a system and method for extracting and stripping and separating five alkali metal cations of lithium, sodium, potassium, rubidium and cesium by non-steady flow discrete extraction and stripping. Background Art

[0002] Lithium, rubidium, and cesium are strategic rare metals that hold a crucial strategic position in fields such as national defense, aerospace, catalysts, power batteries, electronic devices, and medicine. Separating and purifying lithium, rubidium, and cesium often faces the challenge of interference from impurities such as potassium and sodium. Lithium, sodium, potassium, rubidium, and cesium all belong to Group IA of the periodic table and often coexist in nature. Their ions possess extremely similar chemical properties, making their separation extremely difficult. Precipitation and ion exchange are the most commonly used separation methods. However, precipitation has the disadvantage that the insoluble compounds formed by the five alkali metal ions have very similar physicochemical properties, resulting in co-precipitation and difficulty in complete separation. In particular, to obtain a higher-purity target alkali metal product, when other coexisting alkali metal ions are present as impurities, existing technologies typically require the use of step-by-step crystallization or graded precipitation methods. This involves multiple steps of separation, followed by repeated adjustment of process parameters, before the target alkali metal ions can be gradually separated and purified. This involves complex separation procedures and a lengthy process. Ion exchange chromatography is a commonly used method to achieve the simultaneous separation of five alkali metal ion coexistence systems. However, due to the limited exchange capacity, adsorption rate and selectivity of the resin functional groups, the separation efficiency is not high. Solvent extraction is an effective means to separate five alkali metal ions. Commonly used extractants include substituted phenols, crown polyethers, acidic phosphates, carboxylic acids, β-diketones, etc. Among them, substituted phenol extractants are the most widely used. 4-tert-Butyl-2-(α-methylbenzyl)phenol (code name: t-BAMBP) is a substituted phenol extractant, which is usually weakly acidic and has many advantages such as high extraction efficiency, easy stripping, recyclability, low price, low water solubility, low volatility, good stability, non-toxicity, strong selectivity, and fast reaction speed. In alkaline aqueous solutions with a pH greater than 10, the order of extraction of alkali metal cations by t-BAMBP is Cs + >Rb + >K + >Na + >Li +. By utilizing the differences in the binding abilities of the five alkali metal cations with t-BAMBP, their separation from each other can be achieved through step-by-step extraction. For example, a lower concentration of t-BAMBP kerosene solution is first used to preferentially extract and separate cesium, and then the concentration of t-BAMBP in the kerosene solution is increased to extract and separate rubidium and other alkali metal ions from the above-mentioned residual aqueous phase, and then the concentration of t-BAMBP is further increased to separate potassium, sodium and lithium. In order to achieve the mutual separation of the coexisting system of five alkali metal ions, the entire process needs to repeatedly adjust the process parameters and separation conditions for multi-step separation, which can easily cause dispersion losses and low metal yields.

[0003] Chinese patent CN106929693A discloses a method for extracting and separating cesium, rubidium, and potassium. First, a mixed aqueous solution containing rubidium, cesium, and potassium is alkali-adjusted to an alkalinity of 0.8 to 1.0 mol / L using sodium hydroxide or potassium hydroxide. Cesium is then preferentially separated from the alkali-adjusted aqueous solution by extraction. The extractant is a 260# solvent oil organic solution of t-BAMBP, wherein the concentration of t-BAMBP is 0.5 to 1.5 mol / L. The saturated organic phase loaded with cesium is first washed with deionized water to remove the co-extracted rubidium. The organic phase after rubidium washing is then stripped with 0.8 to 2 mol / L hydrochloric acid or sulfuric acid aqueous solution to obtain a cesium strip solution, thereby separating cesium from rubidium and potassium. Then, 0.5-1.5 mol / L t-BAMBP solvent oil organic solution is used again to extract and separate rubidium and potassium from the raffinate obtained after cesium extraction. After rubidium extraction, potassium washing, and back extraction, a rubidium back extract is obtained, achieving the separation of rubidium and potassium. This method requires step-by-step extraction and back extraction to separate the coexisting rubidium, cesium, and potassium systems, resulting in a lengthy process.

[0004] Chinese patent CN115124054A discloses a method for separating and extracting rubidium and cesium salts from lithium precipitation mother liquor of lepidolite. The lepidolite mother liquor is first acidified to remove carbonate ions from the solution, then alkalized to obtain an alkaline solution with a pH of 8-10. The alkaline solution is concentrated and solid-liquid separated to obtain a concentrated solution and a potassium-sodium mixed salt. The concentrated solution is then cooled and solid-liquid separated to obtain a rubidium-cesium salt solution and a potassium-sodium mixed salt. The rubidium-cesium salt solution is adjusted to a pH of 10-12 by adding alkali. Cesium is first extracted using t-BAMBP. The resulting cesium-loaded organic phase is washed, stripped, and crystallized to obtain the cesium salt. The cesium-extracted solution is then adjusted to a pH of 12-14 by adding alkali. Rubidium is extracted again using t-BAMBP. The resulting rubidium-loaded organic phase is washed, stripped, and crystallized to obtain the rubidium salt. Finally, the rubidium-extracted solution is subjected to lithium precipitation to obtain the lithium salt. The entire process of separating lithium, sodium, potassium, rubidium and cesium requires repeated adjustment of the solution alkalinity. The process is lengthy and can easily cause the dispersion and loss of alkali metal ions during the process.

[0005] Chinese patent CN107937733B discloses a process for extracting lithium, potassium, rubidium, and cesium from lithophile mica. First, lithophile mica powder is mixed with a flux and calcined. The resulting lithophile mica clinker is then leached in water at room temperature to produce a leachate containing lithium, potassium, rubidium, and cesium. Alkali is then added to the leachate to adjust the pH. After filtration, carbonate is added to the filtrate to precipitate and remove impurities. The purified solution is evaporated and concentrated to a lithium concentration of 10-20 g / L. Saturated sodium carbonate is added to precipitate and separate the lithium, and the lithium carbonate is filtered to obtain lithium carbonate. The alkalinity of the lithium precipitated mother liquor is first adjusted to a hydroxide concentration of 0.1-0.4 mol / L. Cesium is then preferentially extracted and separated using t-BAMBP, and stripping produces a cesium salt. The alkalinity of the cesium-extracted solution is again adjusted to a hydroxide concentration of 0.5-1.0 mol / L. Rubidium is then extracted using t-BAMBP, and stripping produces a rubidium salt. After rubidium extraction, the solution is evaporated and concentrated to obtain potassium salt. This method of separating a mixed aqueous solution containing lithium, potassium, rubidium, and cesium requires multiple steps of precipitation, alkali adjustment, extraction, and separation, making the process lengthy.

[0006] Chinese patent CN108330298B discloses a method for extracting rubidium, cesium, lithium, and potassium from polymetallic mica ore. First, the polymetallic mica ore and additives are mixed uniformly and then roasted to obtain roasted sand. Water is added to the roasted sand for leaching to obtain a leachate. Sodium hydroxide is added to the leachate to remove impurities such as manganese, magnesium, and calcium, and then evaporated and concentrated. After concentration, ethanol is added to precipitate and separate potassium and sodium, obtaining a mixed salt of potassium sulfate and sodium sulfate. Potassium chloride is then added to the mixed salt of potassium sulfate and sodium sulfate to form a saturated solution. Methanol is then added for salting out. Potassium chloride is again added to the resulting salted product to form a saturated solution, which is then allowed to stand for recrystallization to obtain potassium sulfate, thereby separating potassium and sodium. Sodium carbonate is first added to the solution after the potassium and sodium precipitation separation using ethanol to precipitate and separate lithium. Rubidium and cesium are then extracted and separated using a kerosene and xylene solution of t-BAMBP, and hydrochloric acid or aqueous sulfuric acid is used as the stripping agent to prepare rubidium and cesium salts, respectively. The entire separation process is complicated and the alkali metal yield is not high.

[0007] Chinese patent CN116219203A discloses a method for recovering lithium, rubidium, and cesium from lepidolite ore. First, lepidolite concentrate is mixed with gypsum and calcium carbonate and then roasted. The resulting roasted sand is then leached with water or a lithium-ion aqueous solution. The resulting leachate is purified with lime slurry and a carbonate-containing aqueous solution. The resulting purified slurry is separated into solid and liquid and evaporated and concentrated to produce a potassium-sodium mixed salt and a solution after potassium and sodium removal. The solution after potassium and sodium removal is treated with an adsorption resin to remove calcium and magnesium, and sodium carbonate is added to precipitate lithium to produce lithium carbonate and a lithium-precipitated mother liquor. The lithium-precipitated mother liquor is then subjected to countercurrent continuous extraction with a 10% to 30% by volume t-BAMBP + kerosene solution and stripped with aqueous sulfuric acid to produce a cesium-rich strip solution. The cesium-extracted solution obtained after cesium extraction is again subjected to countercurrent continuous extraction with a t-BAMBP kerosene solution and then stripped with a higher concentration of aqueous sulfuric acid to produce a rubidium-rich strip solution. After evaporation and crystallization of the cesium-rich strip solution and the rubidium-rich strip solution, cesium sulfate and rubidium sulfate are obtained. The entire process of separating the alkali metals lithium, sodium, potassium, rubidium, and cesium is also very lengthy.

[0008] In summary, existing separation processes for complex solutions containing the coexistence of five alkali metal ions—lithium, sodium, potassium, rubidium, and cesium—are extremely complex and lengthy. Due to the extremely similar chemical properties of these five alkali metal ions, various publicly reported methods have struggled to achieve efficient separation of these five alkali metal ions. Summary of the Invention

[0009] In response to the problems existing in the prior art, one objective of the present invention is to provide a method for extracting and separating five alkali metal cations: lithium, sodium, potassium, rubidium, and cesium. Specifically, it relates to a method for extracting and separating these five alkali metal cations using a non-steady flow discrete extraction method. Based on the differences in the binding abilities of these five alkali metal cations with extractant molecules and their extraction reaction rates, a periodic flow pump is used to continuously inject organic extractant oil droplets or hollow oil droplets encapsulating bubbles into a mixed aqueous solution containing all five alkali metal cations, or at least three of these alkali metal cations. The number of organic extractant oil droplets or hollow oil droplets encapsulating bubbles varies periodically with the pumping rate of the periodic flow pump. These organic extractant oil droplets rise upward in a non-steady discrete flow state, continuously contacting the mixed aqueous solution of alkali metal ions moving downward in countercurrent. This method achieves step-by-step extraction and separation of the five alkali metal cations from the mixed aqueous solution, with the five alkali metal cations exiting in the order of cesium > rubidium > potassium > sodium > lithium.

[0010] To achieve the above-mentioned purpose and method, the present invention provides the following technical solutions:

[0011] In a first aspect, the present invention provides a system for separating alkali metal ions by non-steady flow discrete extraction, the system comprising a non-steady flow discrete extraction device, a periodic flow pump, a first intermediate liquid storage device, a first liquid replenishing device, a second liquid replenishing device and a first collection device.

[0012] The non-steady flow discrete extraction device is composed of a hollow straight tube column and an oil distributor.

[0013] The ratio of the length of the hollow straight tube column to its inner diameter is 10:1 to 20:1.

[0014] The length of the hollow straight tube column should be such that after the organic extractant oil droplets or hollow oil droplets encapsulated by bubbles pass through the straight tube, the organic extractant extracts a certain alkali metal ion at a maximum value. When the floating organic extractant oil droplets or hollow oil droplets encapsulated by bubbles have extracted alkali metal ions at a saturated load, increasing the length of the straight tube is no longer beneficial. During actual operation, the length of the hollow straight tube should also take into account the flow rate of the alkali metal mixed aqueous solution pumped into the hollow straight tube column from top to bottom through the straight tube, ensuring that the organic extractant oil droplets or hollow oil droplets encapsulated by bubbles float up and pass through the straight tube and just reach their saturated extraction load.

[0015] If the inner diameter of the hollow straight tube column is too small, the organic extractant oil droplets or hollow oil droplets encapsulating the bubbles will coalesce or adhere to the wall, which will hinder the organic extractant oil droplets or hollow oil droplets encapsulating the bubbles from smoothly passing through the hollow straight tube column in a discrete dispersed phase state. If the inner diameter of the hollow straight tube column is too large, the mixed aqueous solution containing alkali metal ions will not be fully extracted and will flow out of the straight tube, resulting in a decrease in the separation yield. Furthermore, the inner diameter of the hollow straight tube column needs to match the inner diameter of the nozzle of the oil distributor spray head so that the droplets of the organic solution are of appropriate size and can pass through smoothly.

[0016] Preferably, the length of the hollow straight tube column is 20.0 to 100.0 cm, and the inner diameter is 1.0 to 10.0 cm; for example, the length of the hollow straight tube column is 20.0 cm, 30.0 cm, 40.0 cm, 50.0 cm, 60.0 cm, 70.0 cm, 80.0 cm, 90.0 cm, 100.0 cm, etc., and the inner diameter thereof is 1.0 cm, 2.0 cm, 3.0 cm, 4.0 cm, 5.0 cm, 6.0 cm, 7.0 cm, 8.5 cm, 10.0 cm, etc., respectively.

[0017] The hollow straight tube column is provided with an oil phase overflow outlet located on one side of the top tube wall, a water phase inlet located on the other side of the upper tube wall and lower than the oil phase overflow outlet, and a water phase outlet located on one side of the lower tube wall.

[0018] The oil distributor is located at the bottom end of the hollow straight pipe column and is connected to the hollow straight pipe column by a flange.

[0019] The oil distributor consists of an injection head, an oil distributor oil chamber and an oil distributor air chamber.

[0020] The oil distributor's injection head is composed of a group of hollow straight tubes nested inside and outside; wherein, the inner tube is the air inlet pipe, whose inner diameter is 0.05-0.5 mm, and the inner tube is connected to the air chamber of the oil distributor; the outer tube is the oil inlet pipe, whose inner diameter is 0.6-1.0 mm, and the slit gap between the inner wall of the outer tube and the outer wall of the inner tube is connected to the oil chamber of the oil distributor; the number of the oil distributor's injection heads is determined by the inner diameter of the hollow straight tube column, and is evenly distributed at the bottom of the hollow straight tube column according to the outer tube diameter of each individual injection head; the nozzle of the oil distributor's injection head is facing the top of the hollow straight tube.

[0021] The spray head of the oil distributor is composed of hollow straight tubes nested inside and outside. Its purpose is to obtain a solid oil droplet dispersion phase containing the extractant from the nozzle of the oil distributor when no air is introduced into the inner tube of the spray head and only the slit gap between the inner wall of the outer tube and the outer wall of the inner tube is pumped into the organic solution containing the extractant; when air is introduced into the inner tube of the spray head and the organic solution containing the extractant is pumped into the slit gap between the inner wall of the outer tube and the outer wall of the inner tube, a hollow oil droplet dispersion phase containing the extractant is obtained from the nozzle of the oil distributor.

[0022] The purpose of dispensing the dispersed phase of hollow oil droplets containing the extractant from the nozzle of the oil distributor nozzle is to overcome the resistance to the upward buoyancy of the oil droplets caused by the downward countercurrent movement of the alkali metal ion mixed aqueous solution pumped into the hollow straight tube column. When the flow rate of the alkali metal ion mixed aqueous solution pumped into the hollow straight tube column from top to bottom through the hollow straight tube column is too high, this helps to increase the upward buoyancy of the dispersed phase of the oil droplets, ensuring that the organic extractant oil droplets can smoothly float up and pass through the hollow straight tube column.

[0023] The purpose of controlling the inner diameter of the oil distributor nozzle's outer tube is to control the appropriate size of organic extractant oil droplets or the size of hollow oil droplets encapsulating bubbles. The inner diameter of the oil distributor nozzle's outer tube must match the inner diameter of the hollow straight tubular column of the unsteady flow discrete extraction device. This ensures that the dispersed phase of extractant oil droplets or hollow oil droplets encapsulating bubbles ejected from the nozzle of the oil distributor nozzle is of the appropriate size and can smoothly float upward through the hollow straight tubular column.

[0024] An air inlet is provided at the lower end of the oil distributor air chamber, and the air inlet is communicated with the oil distributor air chamber.

[0025] The side wall of the oil chamber of the oil distributor is provided with an oil inlet, which is communicated with the oil chamber of the oil distributor.

[0026] A porous bubble breaking baffle is provided at the upper port of the hollow straight tube column. The porous bubble breaking baffle is located below the oil phase overflow outlet at the top of the hollow straight tube column and above the water phase inlet on the upper tube wall.

[0027] The porous bubble-breaking plate is internally provided with a contracting, bell-shaped channel. This is intended to cause oil droplets containing the extractant or hollow oil droplets encapsulating bubbles to coalesce, or coalesce after breaking the bubbles, when they pass through the porous bubble-breaking baffle, yielding a loaded organic phase after extraction.

[0028] The periodic flow pump is a peristaltic pump whose pumping flow rate changes periodically.

[0029] The first intermediate liquid storage device is a liquid storage tank with stirring, in which a stirring device is provided.

[0030] The first fluid replenishing device and the second fluid replenishing device are fluid storage tanks.

[0031] The outlet of the first intermediate liquid storage device is connected to the inlet of the periodic flow pump.

[0032] The inlet of the first intermediate liquid storage device is connected to the outlets of the first liquid replenishing device and the second liquid replenishing device respectively.

[0033] The outlet of the periodic flow pump is connected to the oil inlet on the side wall of the oil chamber of the oil distributor of the non-steady flow discrete extraction device.

[0034] The first collecting device is an automatic stepping collector, and the inlet of the automatic stepping collector is connected to the oil phase overflow port at the top of the hollow straight tube column.

[0035] In a second aspect, the present invention provides a method for separating alkali metal ions by non-steady flow discrete extraction, comprising the following steps:

[0036] (1) Pumping a mixed aqueous solution containing alkali metal ions into the water phase inlet at the upper part of the non-steady flow discrete extraction device at a pumping volume flow rate of 0.0 to 20.0 mL / min; the mixed aqueous solution containing alkali metal ions moves from top to bottom in the device, and then flows out from the water phase outlet at the lower part of the non-steady flow discrete extraction device to obtain a raffinate aqueous phase; pumping an organic solvent from a first liquid replenishing device into a first intermediate liquid storage device with stirring, then closing the outlet valve of the first liquid replenishing device, and continuously pumping an organic extractant from a second liquid replenishing device into the first intermediate liquid storage device with stirring; at the same time, turning on a periodic flow pump, setting a periodic increase range and a periodic value of the pumping flow, and pumping an organic solvent from the first intermediate liquid storage device into the oil phase inlet at the lower part of the non-steady flow discrete extraction device. The organic solution containing the extractant obtained after mixing is pumped into the oil chamber of the oil distributor; then, air is pumped into the air inlet at the bottom end of the non-steady flow discrete extraction device; the extractant-containing oil droplets or hollow oil droplets encapsulating bubbles ejected from the nozzle of the oil distributor nozzle are in a discrete dispersed phase state, and the number of oil droplets varies with the periodic flow rate of the periodic flow pump, and the concentration of the organic extractant in the oil droplets varies with the concentration of the extractant in the first intermediate liquid storage device; the extractant-containing oil droplets or hollow oil droplets encapsulating bubbles moving in a discrete flow come into countercurrent contact with the mixed aqueous solution containing alkali metal ions contained in the device from bottom to top, and finally, after breaking and coalescing at the top porous bubble breaking baffle of the non-steady flow discrete extraction device, flow out from the top oil phase overflow outlet to obtain a loaded organic phase;

[0037] (2) continuously collecting in batches the loaded organic phase flowing out of the oil phase overflow port at the top of the non-steady flow discrete extraction device in step (1); wherein the duration of each batch collection is independently selected from 5 to 40 minutes. For example, the duration of each batch collection is 5 minutes, that is, the loaded organic phase obtained within 0 to 5 minutes is collected, and then the loaded organic phase obtained within 5 to 10 minutes is collected, and so on, to obtain loaded organic phases extracted with different alkali metal ions in different time periods; the duration of each batch collection is controlled in order to control the outflow volume of the organic phase. The duration of each batch collection is determined according to the flow rate of the countercurrent contact, thereby controlling the volume of the organic solution effluent within the time period, and thereby obtaining an enriched organic phase in which the loading concentration of a certain alkali metal ion is much higher than that of other coexisting alkali metal ions;

[0038] (3) The loaded organic phases obtained in step (2) and extracted with different alkali metal ions in different time periods are mixed with a hydrochloric acid or sulfuric acid aqueous solution with a concentration of 0.1 to 2.0 mol / L at a volume ratio of 1:1 to 10:1 for 0.1 to 2 hours for back extraction; after oil-water phase separation, the lower aqueous phases are collected respectively to obtain enriched aqueous solutions containing a certain alkali metal ion concentration much higher than other coexisting alkali metal ions.

[0039] According to a specific embodiment of the present invention, the mixed aqueous solution containing alkali metal ions in step (1) is an alkaline aqueous solution containing a combination of at least three of the five alkali metal cations of lithium, sodium, potassium, rubidium, and cesium, the total concentration of alkali metal ions is 0.1 to 5 g / L, the pH value of the alkaline aqueous solution is greater than 12.5, and the alkalinity is higher than pH 14 is expressed as a molar concentration; the organic extractant is 4-tert-butyl-2-(α-methylbenzyl)phenol (t-BAMBP); the organic solvent is commercially available kerosene or xylene; the organic solution containing the extractant is prepared by dissolving t-BAMBP in kerosene or xylene and mixing them; the volume percentage of t-BAMBP in the organic solution containing the extractant increases continuously from 1% to 30% at a rate of increase of 0.5% to 3% per minute; the volume flow rate of the organic solution containing the extractant ejected from the nozzle of the oil distributor nozzle increases periodically and continuously from 0.5 mL / min to 5.0 mL / min, with a cycle value of one cycle every 1 to 10 minutes and a rate of increase of 0.5 to 5.0 mL per minute in each cycle; the volume flow rate of air pumped into the air inlet at the bottom end of the device is 0 to 5.0 mL / min.

[0040] According to a specific embodiment of the present invention, step (1) controls the volume flow rate of the mixed aqueous solution containing alkali metal ions pumped in from the upper aqueous phase inlet of the non-steady flow discrete extraction device, and controls the volume flow rate of the organic solution containing the extractant sprayed out from the nozzle of the oil distributor spray head. The purpose is to control the residence time of the mixed aqueous solution containing alkali metal ions in the hollow straight tube column of the device, and to make the residence time of the dispersed phase of the hollow oil droplets containing the extractant oil droplets or the hollow oil droplets encapsulating the bubbles pass through the hollow straight tube column just reach the residence time required for its saturated extraction load. A too large volume flow rate of the mixed aqueous solution containing alkali metal ions is not conducive to the floating of the dispersed phase of the hollow oil droplets containing the extractant oil droplets or the hollow oil droplets encapsulating the bubbles, and may even form turbulence or liquid flooding. A too large jet flow rate of the organic solution containing the extractant sprayed out from the nozzle of the oil distributor spray head is not conducive to the dispersion of the organic droplets, and may even coalesce or form a liquid column spray. The jet flow rate of the extractant-containing organic solution ejected from the nozzle of the oil dispenser nozzle should not be too small, otherwise the separation time will be prolonged, or the alkali metal ions in the pumped alkali metal aqueous solution will not be fully extracted and will flow out of the device, resulting in a decrease in the separation yield. Furthermore, the volume flow rate of the air pumped into the air inlet at the bottom end of the device is controlled, with the purpose of spraying hollow oil droplets containing the extractant from the nozzle of the oil dispenser nozzle. The volume flow rate of the air pumped into the air inlet at the bottom end of the device needs to match the jet flow rate of the extractant-containing organic solution ejected from the nozzle of the oil dispenser nozzle. When the jet flow rate of the extractant-containing organic solution is too small or the volume flow rate of the air pumped into the air inlet at the bottom end of the device is too large, it is not conducive to the stable formation of the hollow oil droplet dispersed phase, and may even form a mixed dispersed phase entrained by bubbles and solid oil droplets, resulting in turbulent disturbances or flooding, which will destroy the chromatographic separation effect of the alkali metal ions. If the injection flow rate of the extractant-containing organic solution is too high or the volumetric flow rate of air pumped into the device's bottom air inlet is too low, the dispersed phase ejected from the oil distributor nozzle is primarily composed of solid oil droplets of the organic extractant. If the flow rate of the alkali metal mixed aqueous solution pumped into the hollow straight column from top to bottom is too high, the solid oil droplets of the organic extractant will have difficulty floating upward, and chromatographic separation of the alkali metal ions will be impossible.

[0041] According to a specific embodiment of the present invention, the purpose of using a periodic flow pump in step (1) is to obtain a periodically increasing number of extractant-containing oil droplets or hollow oil droplets encapsulating bubbles by setting the periodic increase range and periodic value of the pumped flow rate, thereby obtaining a discrete flow of extractant-containing oil droplets or hollow oil droplets encapsulating bubbles with a periodic change in flow rate.

[0042] According to a specific embodiment of the present invention, in step (1), the organic solvent is pumped from the first liquid replenishing device into the first intermediate liquid storage device with stirring, and then the outlet valve of the first liquid replenishing device is closed, and the organic extractant is continuously pumped from the second liquid replenishing device into the first intermediate liquid storage device with stirring. The purpose is to obtain an organic solution with a continuously increasing t-BAMBP concentration in the first intermediate liquid storage device by controlling the pumping flow rate of the organic extractant.

[0043] According to a specific embodiment of the present invention, the continuous batch collection of the loaded organic phase flowing out of the oil phase overflow port at the top of the non-steady flow discrete extraction device in step (1) in step (2) is carried out by the automatic stepping collector of the first collecting device; the automatic stepping collector rotates at a constant speed to perform continuous batch collection; wherein the time interval of the constant speed rotation of the automatic stepping collector is 5 to 40 minutes.

[0044] The system for non-steady flow discrete extraction and separation of alkali metal ions described in the present invention can be used alone or in series in multiple stages.

[0045] According to a specific embodiment of the present invention, when the system for separating alkali metal ions by non-steady flow discrete extraction is used in multiple stages in series, the raffinate aqueous phase flowing out from the lower aqueous phase outlet of the non-steady flow discrete extraction device of the upstream system is continuously pumped into the upper aqueous phase inlet of the non-steady flow discrete extraction device of the downstream system, and the loaded organic phases flowing out from the oil phase overflow outlet at the top of the non-steady flow discrete extraction device of each individual system are collected respectively.

[0046] According to a specific embodiment of the present invention, when the non-steady flow discrete extraction system for separating alkali metal ions is used in multiple stages in series, the volumetric flow rate of the mixed aqueous solution containing alkali metal ions pumped into the upper aqueous phase inlet of each non-steady flow discrete extraction device is controlled to be between 1.0 and 100.0 mL / min; and the volumetric flow rate of the mixed aqueous solution containing alkali metal ions pumped into the upper aqueous phase inlet of each device is equal. Controlling the volumetric flow rate of the mixed aqueous solution containing alkali metal ions pumped into the upper aqueous phase inlet of the non-steady flow discrete extraction device is intended to control the residence time of the mixed aqueous solution containing alkali metal ions within the hollow straight tubular column of the device, thereby achieving better pairwise separation between different alkali metal ions. Controlling the volumetric flow rate of the mixed aqueous solution containing alkali metal ions pumped into the upper aqueous phase inlet of each device is intended to maintain the same total liquid level at the oil phase overflow port at the top of each device stage, ensuring smooth phase separation of the oil and water phases at the top of each device stage, and ensuring that the resulting loaded organic phase can flow smoothly out of the oil phase overflow port.

[0047] According to a specific embodiment of the present invention, when the system for separating alkali metal ions by non-steady flow discrete extraction is used in multiple stages in series, the volume percentage of t-BAMBP in the organic solution containing the extractant pumped into the lower oil phase inlet of the non-steady flow discrete extraction device at each stage increases continuously from 1% to 30%, and the rate of increase increases step by step; the rate of increase of the volume percentage of t-BAMBP in the organic solution pumped into the lower oil phase inlet of the downstream device is 1.0 to 3.0 times the rate of increase of the volume percentage of t-BAMBP in the organic solution pumped into the lower oil phase inlet of the upstream device. For example, if the volume percentage of t-BAMBP pumped into the lower oil phase inlet of the non-steady flow discrete extraction device in the first-stage system increases continuously from 1% to 30% at a rate of 0.5% per minute, then the volume percentage of t-BAMBP pumped into the lower oil phase inlet of the non-steady flow discrete extraction device in the second-stage system increases continuously from 1% to 30% at a rate of 0.5% per minute, or 1.0% per minute, or 1.5% per minute; and so on.

[0048] According to a specific embodiment of the present invention, when the system for separating alkali metal ions by non-steady flow discrete extraction is used in multiple stages in series, the volume flow rate of the organic solution containing the extractant sprayed from the nozzle of the oil distributor spray head at the bottom end of the downstream non-steady flow discrete extraction device is kept equal to the volume flow rate of the organic solution containing the extractant sprayed from the nozzle of the oil distributor spray head at the bottom end of the upstream non-steady flow discrete extraction device; further, it can also be determined separately based on the change in the mutual concentration ratio of the five alkali metal cations of lithium, sodium, potassium, rubidium and cesium in the mixed aqueous solution containing alkali metal ions flowing out of the lower aqueous phase outlet of the upstream non-steady flow discrete extraction device.

[0049] The method and system for the non-steady flow discrete extraction and separation of alkali metal ions described herein operate according to the principle that when a kerosene or xylene solution of 4-tert-butyl-2-(α-methylbenzyl)phenol (t-BAMBP) is used to extract a mixed aqueous solution containing lithium, sodium, potassium, rubidium, cesium, or a combination of at least three of these alkali metal cations, the extraction reaction rates of the five alkali metal cations, lithium, sodium, potassium, rubidium, and cesium, follow the order of cesium > rubidium > potassium > sodium > lithium, from fastest to slowest. Furthermore, when organic extractant oil droplets or hollow oil droplets encapsulating bubbles are continuously sprayed into the mixed aqueous solution containing alkali metal cations, a periodic flow pump is used to produce a periodically increasing number of extractant oil droplets or hollow oil droplets encapsulating bubbles, thereby producing a discrete flow of extractant oil droplets or hollow oil droplets encapsulating bubbles with a periodic increasing flow rate. The dispersed phase of organic extractant oil droplets or hollow oil droplets encapsulating bubbles moves upward in an unsteady discrete flow state, countercurrently contacting a mixed aqueous solution of alkali metal ions moving downward from above. Alkali metal ions with fast extraction reaction rates are preferentially extracted by the organic extractant oil droplets or hollow oil droplets encapsulating bubbles. These droplets rise with the organic extractant oil droplets or hollow oil droplets encapsulating bubbles to the porous bubble-breaking baffle at the top of the unsteady flow discrete extraction device, where they break and coalesce. They then preferentially flow out of the top oil phase overflow outlet, resulting in an enriched organic phase with a significantly higher loading concentration of a particular alkali metal ion than other coexisting alkali metal ions. The t-BAMBP concentration in the extractant oil droplets or hollow oil droplets encapsulating bubbles ejected from the oil distributor nozzle of the unsteady flow discrete extraction device continuously increases, and the number of droplets ejected increases periodically. This is intended to increase the differences in the extraction reaction rates of the five alkali metal cations: lithium, sodium, potassium, rubidium, and cesium, thereby enhancing their pairwise separation efficiency. By controlling the pumping volume flow rate of the mixed aqueous solution containing alkali metal ions, the residence time of the mixed aqueous solution of alkali metal ions in the hollow straight tube column of the non-steady flow discrete extraction device is controlled; by controlling the volume flow rate of the organic solution containing the extractant sprayed from the nozzle of the oil distributor spray head and the concentration of the extractant t-BAMBP in the organic solution, the reaction rate of the organic extractant oil droplets or hollow oil droplets coated with bubbles in extracting five alkali metal cations of lithium, sodium, potassium, rubidium and cesium is controlled. The five alkali metal cations in the mixed aqueous solution can be extracted step by step and separated from each other in pairs, and flow out step by step in the order of cesium>rubidium>potassium>sodium>lithium, which is similar to chromatographic separation, with a simple process and high separation efficiency. When multiple stages of the non-steady flow discrete extraction system are connected in series, the pumping volume flow rate of the appropriate alkali metal ion mixed aqueous solution is controlled, and the volume flow rate of the extractant-containing organic solution pumped in from the lower oil phase inlet of each stage of the non-steady flow discrete extraction device and the rate of increase of the volume percentage of t-BAMBP in the organic solution are controlled. Different enriched organic phases containing a certain alkali metal ion load concentration much higher than other coexisting alkali metal ions can be obtained from the upper oil phase overflow outlet of each single-stage non-steady flow discrete extraction device in the series in the order of cesium > rubidium > potassium > sodium > lithium.

[0050] The key to achieving the aforementioned working principle of the non-steady flow discrete extraction and separation method and system for alkali metal ions described herein lies in obtaining extractant oil droplets or hollow oil droplets encapsulating bubbles with a continuously increasing t-BAMBP concentration through a first intermediate liquid storage device, obtaining a periodically increasing number of extractant oil droplets or hollow oil droplets encapsulating bubbles through a periodic flow pump, and thereby obtaining a discrete flow of extractant oil droplets or hollow oil droplets encapsulating bubbles with a periodically increasing flow rate. The flow rate of the discrete flow of organic extractant oil droplets or hollow oil droplets encapsulating bubbles increases in a non-steady, periodic manner, and the t-BAMBP concentration in the droplets also increases continuously. Under the continuous elution and extraction action of the organic extractant oil droplets or hollow oil droplets encapsulating bubbles as a mobile phase, this helps to amplify the differences in the extraction reaction rates of the five alkali metal cations: lithium, sodium, potassium, rubidium, and cesium, thereby enhancing their mutual separation. In this process, any factor that disrupts the formation of a discrete flow of the dispersed phase of the organic extractant oil droplets or hollow oil droplets encapsulating bubbles will impair the chromatographic separation of the alkali metal ions.

[0051] Another object of the present invention is to provide a method for stripping and separating five alkali metal ions: lithium, sodium, potassium, rubidium, and cesium. Specifically, it relates to a method for stripping and separating these five alkali metal ions by unsteady flow discrete stripping. Based on the differences in stripping reaction rates of these five alkali metal ions, a periodic variable frequency pulse pump is used to continuously spray droplets of hydrochloric acid or aqueous sulfuric acid as a stripping agent into an extracted loaded organic phase containing all or at least three of these alkali metal ions. The number of stripping agent droplets varies periodically with the pulse frequency of the periodic variable frequency pulse pump. These droplets sink downward in an unsteady discrete flow state, continuously engaging in countercurrent with the alkali metal ion-loaded organic phase moving upward from below. This allows for stepwise stripping and elution of the five alkali metal cations in the loaded organic phase, separating them pairwise. The droplets then exit in the order of lithium > sodium > potassium > rubidium > cesium.

[0052] To achieve the above-mentioned purpose and method, the present invention provides the following technical solutions:

[0053] In the first aspect, the present invention provides a system for separating alkali metal ions by non-steady flow discrete stripping, which includes a non-steady flow discrete stripping device, a periodic variable frequency pulse pump, a second intermediate liquid storage device, a third liquid replenishing device, a fourth liquid replenishing device and a second collection device.

[0054] The non-steady flow discrete stripping device is composed of a hollow straight tube column, an oil phase chamber, a water phase chamber and a water distributor.

[0055] The ratio of the length of the hollow straight tube column to its inner diameter is 10:1 to 20:1.

[0056] The length of the hollow straight tube column should be such that after the hydrochloric acid or sulfuric acid aqueous solution droplets pass through the straight tube, the concentration of a certain alkali metal ion in the hydrochloric acid or sulfuric acid aqueous solution droplets just reaches its stripping reaction equilibrium concentration as the maximum value. When the sinking hydrochloric acid or sulfuric acid aqueous solution droplets strip the alkali metal ions to reach their stripping reaction equilibrium concentration, it is no longer beneficial to increase the length of the straight tube. In actual operation, the length of the hollow straight tube should also take into account the flow rate of the alkali metal ion-loaded organic phase pumped into the hollow straight tube column from bottom to top through the straight tube, so as to ensure that the hydrochloric acid or sulfuric acid aqueous solution droplets just reach their stripping reaction equilibrium concentration after passing through the straight tube.

[0057] If the inner diameter of the hollow straight tube column is too small, the hydrochloric acid or sulfuric acid aqueous solution droplets will coalesce and adhere to the wall to form a channeling phenomenon, which is not conducive to the hydrochloric acid or sulfuric acid aqueous solution droplets passing through the hollow straight tube column in a discrete dispersed phase state. If the inner diameter of the hollow straight tube column is too large, the loaded organic phase containing alkali metal ions will not be completely back-extracted and will flow out of the straight tube, resulting in a decrease in the separation yield. Furthermore, the inner diameter of the hollow straight tube column needs to match the inner diameter of the nozzle of the water distributor spray pipe so that the stripping solution droplets are of appropriate size and can pass through smoothly.

[0058] Preferably, the length of the hollow straight tube column is 30.0 to 200.0 cm, and the inner diameter is 3.0 to 10.0 cm; for example, the length of the hollow straight tube column is 30.0 cm, 40.0 cm, 50.0 cm, 60.0 cm, 70.0 cm, 80.0 cm, 90.0 cm, 100.0 cm, 110.0 cm, 120.0 cm, 140.0 cm, 160.0 cm, 180.0 cm, 200.0 cm, etc., and the inner diameter thereof is 3.0 cm, 3.5 cm, 4.0 cm, 4.5 cm, 5.0 cm, 5.5 cm, 6.0 cm, 6.5 cm, 7.0 cm, 7.5 cm, 8.0 cm, 8.5 cm, 9.0 cm, 10.0 cm, etc., respectively.

[0059] An oil inlet is provided on one side of the lower pipe wall of the hollow straight pipe column.

[0060] The oil phase chamber is located at the top of the hollow straight tube column and is connected to the hollow straight tube column by a flange.

[0061] The water phase chamber is located at the bottom end of the hollow straight tube column and is connected to the hollow straight tube column by a flange.

[0062] The oil phase chamber is provided with an oil phase overflow outlet located on one side of the top tube wall.

[0063] The water phase chamber is provided with a water phase outlet located on one side of the bottom tube wall.

[0064] The water distributor is located at the upper part of the hollow straight pipe column and below the flange connecting the oil phase chamber and the hollow straight pipe column.

[0065] The water distributor comprises a water inlet, a diversion cavity, a water spraying orifice plate and a water spraying pipe.

[0066] The upper port of the water spray pipe is communicated with the guide cavity of the water distributor and is welded and fixed with the orifice of the water spray orifice plate in a one-to-one correspondence.

[0067] The inner diameter of the water spray pipe is 2.0~5.0mm; the ratio of the length to the inner diameter of the water spray pipe is 5:1~8:1; for example, the inner diameter of the water spray pipe is 2.0mm, 2.5mm, 3.0mm, 3.5mm, 4.0mm, 4.5mm, 5.0mm, etc., and its corresponding length is 10.0mm, 14.0mm, 18.0mm, 22.0mm, 26.0mm, 34.0mm, 40.0mm, etc.

[0068] A guide orifice is provided inside the upper end of the spray pipe and is welded to the inner wall of the upper end of the spray pipe. The purpose of providing the guide orifice is to ensure that the stripping liquid entering the diversion chamber of the water distributor from the water distributor inlet flows smoothly through the guide orifice in a dispersed liquid state and enters the corresponding spray pipe below.

[0069] A spring shaft is provided inside the water spray pipe, and the upper end of the spring shaft is connected and fixed to the center hole of the guide orifice plate with a coupling, and the lower end of the spring shaft is provided with one or more sieve plates arranged in upper and lower layers, and the center hole of the sieve plate is connected and fixed to the lower end of the spring shaft with a coupling, and the diameter of the sieve plate matches the inner diameter of the water spray pipe, preferably 1.95 to 4.95 mm; for example, if the inner diameter of the water spray pipe is 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, 5.0 mm, etc., the corresponding diameters of the sieve plates are 1.95 mm, 2.45 mm, 2.95 mm, 3.45 mm, 3.95 mm, 4.45 mm, 4.95 mm, etc.

[0070] The spring shaft provided in the water spray pipe can freely move up and down relative to the inner wall of the water spray pipe and along the length direction of the water spray pipe. When the spring shaft freely moves up and down, it can drive one or more sieve plates fixed at the lower end of the spring shaft to move up and down relative to the inner wall of the water spray pipe.

[0071] A trumpet-shaped channel that contracts upward and downward is provided inside the sieve plate fixed at the lower end of the spring shaft.

[0072] The purpose of the spring shaft driving one or more sieve plates fixed below to move freely up and down is to use the upper and lower contracting trumpet-shaped channels set inside the sieve plates to cut the stripping liquid flowing inside the water spray pipe, so that when it is sprayed out from the nozzle at the lower end of the water spray pipe, it enters the organic phase in the hollow straight tube column in the form of discrete stripping liquid droplets.

[0073] The lower end nozzle of the water spray pipe faces the bottom end of the hollow straight pipe column.

[0074] A first porous water baffle is provided at the upper end of the hollow straight pipe column, and the first porous water baffle is located below the upper flange and above the water distributor.

[0075] A second porous water baffle is provided at the lower end of the hollow straight pipe column. The second porous water baffle is located above the lower flange and below the oil inlet of the lower side wall of the hollow straight pipe column.

[0076] The first and second porous water retaining plates are each provided with a contracting, bell-shaped channel. This is to ensure that when dispersed stripping solution droplets pass through the first and second porous water retaining plates, they coalesce and eventually sink into the aqueous phase chamber at the bottom of the hollow straight tube column, yielding a stripping raffinate.

[0077] The periodic variable frequency pulse pump is a plunger pump with a periodically changing pulse frequency.

[0078] The second intermediate liquid storage device is a liquid storage tank with stirring, which is provided with a stirring device.

[0079] The third fluid replenishing device and the fourth fluid replenishing device are fluid storage tanks.

[0080] The outlet of the second intermediate liquid storage device is connected to the inlet of the periodic variable frequency pulse pump.

[0081] The inlet of the second intermediate liquid storage device is connected to the outlet of the third liquid replenishing device and the outlet of the fourth liquid replenishing device respectively.

[0082] The outlet of the periodic frequency-variable pulse pump is connected to the water inlet of the water distributor of the non-steady-flow discrete stripping device.

[0083] The second collecting device is an automatic stepping collector, and the inlet of the automatic stepping collector is connected to the water phase outlet of the water phase chamber at the lower end of the hollow straight tube column.

[0084] In a second aspect, the present invention provides a method for separating alkali metal ions by non-steady flow discrete stripping, comprising the following steps:

[0085] (1) The loaded organic phase containing alkali metal ions after extraction is pumped into the oil phase inlet at the lower part of the non-steady flow discrete stripping device, and the pumping volume flow rate is 0.0 to 20.0 mL / min; the loaded organic phase containing alkali metal ions moves from bottom to top in the device, and then overflows from the oil phase chamber outlet at the top of the non-steady flow discrete stripping device to obtain the organic phase after stripping; pure water is pumped from the third liquid replenishing device into the second intermediate liquid storage device with stirring, and then the outlet valve of the third liquid replenishing device is closed, and commercially available hydrochloric acid or sulfuric acid is continuously pumped from the fourth liquid replenishing device into the second intermediate liquid storage device with stirring; at the same time, a periodic variable frequency pulse pump is turned on, and the pulse frequency is set to increase periodically. range and period value, the hydrochloric acid or sulfuric acid aqueous solution obtained by mixing is pumped into the second intermediate liquid storage device from the water inlet of the upper water distributor of the non-steady flow discrete stripping device; the stripping liquid droplets sprayed from the nozzle of the water spray pipe at the lower end of the water distributor are in a discrete dispersed phase state, and the number of droplets changes with the pulse frequency of the periodic variable frequency pulse pump, and the concentration of hydrochloric acid or sulfuric acid in the droplets changes with the concentration of hydrochloric acid or sulfuric acid in the second intermediate liquid storage device; the stripping liquid droplets moving in a discrete flow are in countercurrent contact with the alkali metal ion-loaded organic phase contained in the device from top to bottom, and finally, after being aggregated in the water phase chamber at the bottom end of the non-steady flow discrete stripping device, flow out from the bottom water phase outlet to obtain a stripping raffinate;

[0086] (2) continuously collecting the stripping raffinate flowing out of the aqueous phase outlet at the bottom end of the non-steady flow discrete stripping device in step (1) in batches; wherein the duration of each batch collection is independently selected from 5 to 40 minutes; for example, the duration of each batch collection is 5 minutes, that is, the stripping raffinate obtained within 0 to 5 minutes is collected, and then the stripping raffinate obtained within 5 to 10 minutes is collected, and so on, to obtain the stripping raffinate flowing out of the aqueous phase outlet at the bottom end of the non-steady flow discrete stripping device in different time periods; the duration of each batch collection is controlled in order to control the outflow volume of the stripping raffinate, and the duration of each batch collection is determined according to the flow rate of the countercurrent contact, thereby controlling the outflow volume of the stripping raffinate in the time period, and thereby obtaining an enriched aqueous solution in which the concentration of a certain alkali metal ion is much higher than that of other coexisting alkali metal ions.

[0087] According to a specific embodiment of the present invention, the method for preparing the loaded organic phase containing alkali metal ions after extraction in step (1) is as follows: first, 4-tert-butyl-2-(α-methylbenzyl)phenol (t-BAMBP) is dissolved in commercially available kerosene or xylene, and the mixture is mixed to obtain an organic solution containing an extractant; then, the obtained organic solution containing the extractant is mixed with a mixed aqueous solution containing alkali metal ions at a volume ratio of 1:1 to 1:10 for 0.1 to 2 hours for extraction; after oil-water phase separation, the upper organic phase is collected to obtain an organic phase loaded with alkali metal ions; the volume percentage of t-BAMBP in the kerosene or xylene organic solution of t-BAMBP is 10 to 30%; the organic phase loaded with alkali metal ions contains a combination of at least three of the five alkali metal cations of lithium, sodium, potassium, rubidium, and cesium, and the total concentration of alkali metal ions is 0.1 to 5 g / L.

[0088] According to a specific embodiment of the present invention, the method for preparing the loaded organic phase containing alkali metal ions after extraction in step (1) can also be the loaded organic phase flowing out of the oil phase overflow outlet at the top of the non-steady flow discrete extraction device.

[0089] According to a specific embodiment of the present invention, the pumping volume flow rate of the alkali metal ion-laden organic phase is controlled to control the residence time of the alkali metal ion-laden organic phase within the hollow straight tubular column of the non-steady-flow discrete stripping device, so that the concentration of a certain alkali metal ion in the stripped organic phase exiting the oil phase chamber at the top of the hollow straight tubular column is significantly lower than the concentration of other coexisting alkali metal ions. The pumping volume flow rate of the alkali metal ion-laden organic phase should not be too large, otherwise it will hinder the smooth sinking of the dispersed phase of the stripping liquid droplets and may even cause turbulence or flooding.

[0090] According to a specific embodiment of the present invention, the stripping solution in step (1) is an aqueous solution of hydrochloric acid or sulfuric acid, wherein the molar concentration of hydrochloric acid or sulfuric acid increases continuously from 0.1 mol / L to 2.0 mol / L, and the rate of increase is 0.05 to 0.20 mol / L per minute; the pulse frequency of the periodic variable frequency pulse pump increases continuously and periodically from 0.5 Hz to 50 Hz; the volume flow rate of the stripping solution ejected from the nozzle of the water spray pipe at the lower end of the water distributor increases continuously and periodically from 0.5 mL / min to 5.0 mL / min, the period value is one cycle every 1 to 10 minutes, and the rate of increase of the flow rate in each cycle is 0.5 to 5.0 mL per minute.

[0091] According to a specific embodiment of the present invention, the molar concentration of hydrochloric acid or sulfuric acid in the stripping liquid is controlled, and the volume flow rate of the stripping liquid sprayed from the nozzle of the water spray pipe at the lower end of the water distributor is controlled. The purpose is to control the reaction rate of the hydrochloric acid or sulfuric acid aqueous solution droplets in stripping alkali metal ions, so that after the hydrochloric acid or sulfuric acid aqueous solution droplets pass through the hollow straight tube column, the concentration of a certain alkali metal ion in the hydrochloric acid or sulfuric acid aqueous solution droplets just reaches the equilibrium concentration of its stripping reaction, and then an enriched aqueous solution with a certain alkali metal ion concentration much higher than that of other coexisting alkali metal ions is obtained in the aqueous phase chamber at the lower end of the hollow straight tube column.

[0092] According to a specific embodiment of the present invention, the purpose of using a periodic variable frequency pulse pump in step (1) is to enable the spring shaft provided in the water spray pipe to freely extend and retract relative to the inner wall of the water spray pipe and along the length direction of the water spray pipe under the action of the piston pulse of the periodic variable frequency pulse pump.

[0093] According to a specific embodiment of the present invention, the use of a periodic variable frequency pulse pump in step (1) and the control of the volume flow rate of the stripping solution ejected from the nozzle of the water spray pipe at the lower end of the water distributor is also intended to, under the action of the piston pulse of the periodic variable frequency pulse pump, drive one or more sieve plates fixed below the spring shaft to move up and down relative to the inner wall of the water spray pipe, and use the upper and lower contraction trumpet-shaped holes set inside the sieve plates to cut the stripping solution flowing inside the water spray pipe, so that the stripping solution droplets ejected from the nozzle of the water spray pipe at the lower end of the water distributor enter the organic phase in the hollow straight tube column in a discrete dispersed phase state. The volume flow rate of the stripping solution ejected from the nozzle of the water spray pipe at the lower end of the water distributor should not be too large, otherwise it will be detrimental to the dispersibility of the stripping solution droplets, and thus it will be detrimental to the formation of a discrete flow of stripping solution droplets, and even cause them to coalesce or form a liquid column jet, thereby destroying the chromatographic separation effect of the alkali metal ions. The volume flow rate of the stripping liquid sprayed from the nozzle of the water spray pipe at the lower end of the water distributor should not be too small, otherwise the separation time will be prolonged, or the pumped-in alkali metal ion-loaded organic phase will not have time to be completely stripped and will flow out of the device, resulting in a decrease in the separation yield.

[0094] According to a specific embodiment of the present invention, in step (1), pure water is pumped from the third liquid replenishing device into the second intermediate liquid storage device with stirring, and then the outlet valve of the third liquid replenishing device is closed, and commercially available hydrochloric acid or sulfuric acid is continuously pumped from the fourth liquid replenishing device into the second intermediate liquid storage device with stirring. The purpose is to obtain a stripping solution with a continuously increasing concentration of hydrochloric acid or sulfuric acid in the second intermediate liquid storage device by controlling the pumping flow rate of hydrochloric acid or sulfuric acid.

[0095] According to a specific embodiment of the present invention, the continuous batch collection of the stripping raffinate flowing out of the aqueous phase outlet at the bottom end of the non-steady flow discrete stripping device in step (1) in step (2) is carried out by an automatic stepping collector of the second collecting device; the automatic stepping collector rotates at a constant speed to perform continuous batch collection; wherein the time interval of the constant speed rotation of the automatic stepping collector is 5 to 40 minutes.

[0096] The non-steady-flow discrete stripping system for separating alkali metal ions described in the present invention can be used alone or in multiple stages in series.

[0097] According to a specific embodiment of the present invention, when the system for separating alkali metal ions by non-steady flow discrete stripping is used in multiple stages in series, the stripped organic phase overflowing from the oil phase chamber outlet at the top of the non-steady flow discrete stripping device of the upstream system is continuously pumped into the oil phase inlet at the bottom of the non-steady flow discrete stripping device of the downstream system, and the stripping residual liquid flowing out from the bottom water phase outlet of each individual non-steady flow discrete stripping device of the system is collected respectively.

[0098] According to a specific embodiment of the present invention, when the non-steady flow discrete stripping system for separating alkali metal ions is used in multiple stages in series, the volume flow rate of the alkali metal ion-loaded organic phase pumped into the lower oil phase inlet of each non-steady flow discrete stripping device is controlled to be 0.1 to 30.0 mL / min; and the volume flow rate of the alkali metal ion-loaded organic phase pumped into the lower oil phase inlet of each stage is equal. The purpose of controlling the volume flow rate of the alkali metal ion-loaded organic phase pumped into the lower oil phase inlet of the non-steady flow discrete stripping device is to control the residence time of the alkali metal ion-loaded organic phase in the hollow straight tube column of the device to achieve better pairwise separation between different alkali metal ions; the purpose of controlling the volume flow rate of the alkali metal ion-loaded organic phase pumped into the lower oil phase inlet of each stage is to control the total liquid level of the oil phase overflow port at the top of each stage of the device to be equal, and the obtained stripped organic phase can flow out smoothly from the oil phase overflow port.

[0099] According to a specific embodiment of the present invention, when the system for separating alkali metal ions by non-steady-flow discrete stripping is used in multiple stages in series, the concentration of hydrochloric acid or sulfuric acid in the stripping liquid pumped into the water inlet of the upper water distributor of the non-steady-flow discrete stripping device in each stage of the system continuously increases from 0.1 mol / L to 2.0 mol / L, and the increasing rate is increased step by step; the increasing rate of the concentration of hydrochloric acid or sulfuric acid in the stripping liquid pumped into the water inlet of the upper water distributor of the downstream device is 1.0 to 3.0 times the increasing rate of the concentration of hydrochloric acid or sulfuric acid in the stripping liquid pumped into the water inlet of the upper water distributor of the upstream device. For example, in the first-stage system, the concentration of hydrochloric acid or sulfuric acid in the stripping liquid pumped into the water inlet of the upper water distributor of the non-steady-flow discrete stripping device continuously increases from 0.1 mol / L to 2.0 mol / L at a rate of 0.05 mol / L per minute. Then, in the second-stage system, the concentration of hydrochloric acid or sulfuric acid in the stripping liquid pumped into the water inlet of the upper water distributor of the non-steady-flow discrete stripping device continuously increases from 0.1 mol / L to 2.0 mol / L at a rate of 0.05 mol / L per minute, or 0.10 mol / L per minute, or 0.15 mol / L per minute; and so on.

[0100] According to a specific embodiment of the present invention, when the system for separating alkali metal ions by non-steady-flow discrete stripping is used in multiple stages in series, the volume flow rate of the stripping liquid pumped in from the water inlet of the upper water distributor of the downstream non-steady-flow discrete stripping device is kept equal to the volume flow rate of the stripping liquid pumped in from the water inlet of the upper water distributor of the upstream non-steady-flow discrete stripping device; further, it can also be determined separately based on the change in the mutual concentration ratio of the five alkali metal ions of lithium, sodium, potassium, rubidium and cesium in the alkali metal ion-loaded organic phase flowing out of the overflow outlet of the top oil phase chamber of the upstream non-steady-flow discrete stripping device.

[0101] The working principle of the method and system for separating alkali metal ions by non-steady flow discrete stripping described in the present invention is that when an aqueous solution of hydrochloric acid or sulfuric acid is used to strip a loaded organic phase simultaneously containing lithium, sodium, potassium, rubidium, cesium, or a combination of at least three of these alkali metal cations, the stripping reaction rates of the five alkali metal cations, lithium, sodium, potassium, rubidium, and cesium, follow the order of lithium > sodium > potassium > rubidium > cesium from fast to slow. When stripping solution droplets are continuously sprayed into the loaded organic phase containing alkali metal cations, a periodically increasing number of stripping solution droplets is obtained through a periodic variable frequency pulse pump, thereby obtaining a discrete stream of stripping solution droplets with a periodically increasing flow rate. The discrete stream of stripping solution droplets moves from top to bottom and contacts the loaded organic phase moving from bottom to top in countercurrent. Alkali metal ions with a fast stripping reaction rate are preferentially stripped and, after sinking with the stripping solution droplets into the bottom aqueous phase chamber of the non-steady flow discrete stripping device and coalescing, preferentially flow out of the bottom aqueous phase outlet, resulting in an enriched aqueous solution with a significantly higher concentration of a particular alkali metal ion than other coexisting alkali metal ions. The concentration of hydrochloric acid or sulfuric acid in the stripping solution droplets ejected from the water distributor nozzle of the non-steady flow discrete stripping device continuously increases, and the number of droplets ejected increases periodically. This is intended to increase the difference in stripping reaction rates among the five alkali metal cations: lithium, sodium, potassium, rubidium, and cesium, thereby enhancing their pairwise separation. By controlling the pumping volume flow rate of the alkali metal ion-loaded organic phase, the residence time of the alkali metal ion-loaded organic phase in the hollow straight tube column of the non-steady flow discrete stripping device is controlled; by controlling the volume flow rate of the stripping liquid sprayed from the nozzle of the water distributor spray pipe and the concentration of hydrochloric acid or sulfuric acid in the stripping liquid, the reaction rate of the hydrochloric acid or sulfuric acid droplets in the stripping of lithium, sodium, potassium, rubidium and cesium is controlled, and the five alkali metal cations in the loaded organic phase can be stripped and eluted step by step and separated from each other, and flow out step by step in the order of lithium>sodium>potassium>rubidium>cesium, which is similar to chromatographic separation, simple process and high separation efficiency. When multiple stages of the non-steady flow discrete stripping system are connected in series, the volume flow rate of the organic phase loaded with alkali metal ions is controlled, and the volume flow rate of the stripping liquid pumped in from the water inlet of the upper water distributor of each stage of the non-steady flow discrete stripping device and the rate of increase of the concentration of hydrochloric acid or sulfuric acid in the stripping liquid are controlled. Different enriched aqueous solutions containing a certain alkali metal ion concentration much higher than other coexisting alkali metal ions can be obtained from the bottom aqueous phase outlet of each single-stage non-steady flow discrete stripping device in the series in the order of lithium > sodium > potassium > rubidium > cesium.

[0102] The key to achieving the above-mentioned working principle of the method and system for separating alkali metal ions by non-steady flow discrete stripping described in the present invention is to obtain stripping solution droplets with continuously increasing hydrochloric acid or sulfuric acid concentrations through a second intermediate liquid storage device, obtain stripping solution droplets with a periodically increasing number through a periodic variable frequency pulse pump, and then obtain a discrete flow of stripping solution droplets with a periodically increasing flow rate. The flow rate of the discrete flow of stripping solution droplets increases in a non-stable periodic manner, and the concentration of hydrochloric acid or sulfuric acid in the stripping solution droplets also increases continuously. Under the continuous elution and stripping action of the stripping solution droplet mobile phase, it helps to amplify the difference in stripping reaction rates of the five alkali metal cations of lithium, sodium, potassium, rubidium, and cesium, and strengthen their mutual separation. In the above process, any factor that disturbs the formation of a discrete flow by the dispersed phase of the stripping solution droplets will destroy the chromatographic separation effect of the alkali metal ions.

[0103] The system for separating alkali metal ions by non-steady flow discrete extraction and the system for separating alkali metal ions by non-steady flow discrete stripping described in the present invention can be used alone or in combination.

[0104] According to a specific embodiment of the present invention, when the system for separating alkali metal ions by non-steady flow discrete extraction and the system for separating alkali metal ions by non-steady flow discrete stripping are used in combination, the loaded organic phase flowing out of the oil phase overflow outlet at the top of the non-steady flow discrete extraction device is continuously pumped into the oil phase inlet at the bottom of the non-steady flow discrete stripping device. The stripping raffinate flowing out of the bottom aqueous phase outlet of the non-steady flow discrete stripping device is continuously collected in batches; wherein the duration of each collection batch is independently selected from 5 to 40 minutes. For example, the duration of each collection batch is 5 minutes, that is, the stripping raffinate obtained within 0 to 5 minutes is collected, and then the stripping raffinate obtained within 5 to 10 minutes is collected, and so on, to obtain the stripping raffinate flowing out of the bottom aqueous phase outlet of the non-steady flow discrete stripping device in different time periods. The duration of each collection batch is controlled in order to control the outflow volume of the stripping raffinate. The duration of each collection batch is determined according to the flow rate of the countercurrent contact, thereby controlling the outflow volume of the stripping raffinate within the time period, thereby obtaining an enriched aqueous solution in which the concentration of a certain alkali metal ion is much higher than that of other coexisting alkali metal ions.

[0105] According to a specific embodiment of the present invention, when the system for separating alkali metal ions by non-steady flow discrete extraction and the system for separating alkali metal ions by non-steady flow discrete stripping are used in combination, the volume flow rate of the organic solution containing the extractant sprayed from the nozzle of the oil distributor nozzle at the lower part of the non-steady flow discrete extraction device is periodically and continuously increased from 0.5 mL / min to 5.0 mL / min, with a cycle value of one cycle every 1 to 10 minutes, and the rate of increase of the flow rate in each cycle is 0.5 to 5.0 mL per minute; the volume percentage of t-BAMBP in the organic solution is continuously increased from 1% to 30%, and the rate of increase is 0.5% to 3% per minute; and the volume flow rate of the alkali metal ion-loaded organic phase flowing out of the oil phase overflow outlet at the top of the upstream non-steady flow discrete extraction device is controlled to be equal to the volume flow rate of the loaded organic phase pumped into the lower oil phase inlet of the downstream non-steady flow discrete stripping device. The purpose of controlling the volume flow rate of the organic solution containing the extractant sprayed from the oil distributor nozzle at the bottom of the non-steady flow discrete extraction device is to control the residence time of the organic phase loaded with alkali metal ions in the hollow straight tube column of the non-steady flow discrete stripping device, thereby obtaining a stripping raffinate with a concentration of a certain alkali metal ion much higher than that of other coexisting alkali metal ions at the bottom aqueous phase outlet of the non-steady flow discrete stripping device.

[0106] According to a specific embodiment of the present invention, when the system for separating alkali metal ions by non-steady flow discrete extraction and the system for separating alkali metal ions by non-steady flow discrete stripping are used in combination, the volume flow rate of the mixed aqueous solution containing alkali metal ions pumped in from the upper aqueous phase inlet of the non-steady flow discrete extraction device is controlled to be 1.0 to 100.0 mL / min; the pulse frequency of the periodic variable frequency pulse pump is periodically and continuously increased from 0.5 Hz to 50 Hz; the volume flow rate of the stripping liquid sprayed from the nozzle of the water distributor spray pipe of the upper water distributor of the non-steady flow discrete stripping device is periodically and continuously increased from 0.5 mL / min to 5.0 mL / min, with a cycle value of one cycle every 1 to 10 minutes, and the rate of increase of the flow rate in each cycle is 0.5 to 5.0 mL per minute; the concentration of hydrochloric acid or sulfuric acid in the stripping liquid is continuously increased from 0.1 to 2.0 mol / L, and the rate of increase is 0.05 to 0.20 mol / L per minute. The purpose of controlling the volumetric flow rate of the mixed aqueous solution containing alkali metal ions pumped in through the upper aqueous phase inlet of the non-steady flow discrete extraction device is to control the residence time of the mixed aqueous solution containing alkali metal ions in the hollow straight tube column of the non-steady flow discrete extraction device, thereby obtaining a loaded organic phase having a significantly higher concentration of a certain alkali metal ion than other coexisting alkali metal ions from the oil phase overflow outlet at the top of the non-steady flow discrete extraction device. The purpose of controlling the volumetric flow rate of the stripping liquid pumped in through the water distributor inlet at the top of the non-steady flow discrete stripping device and controlling the molar concentration of hydrochloric acid or sulfuric acid in the stripping liquid is to obtain a stripping raffinate having a significantly higher concentration of a certain alkali metal ion than other coexisting alkali metal ions from the aqueous phase outlet at the bottom of the non-steady flow discrete stripping device.

[0107] When the non-steady flow discrete extraction and separation system for alkali metal ions and the non-steady flow discrete stripping and separation system for alkali metal ions are used in combination, the operating principle is that when the extraction stage utilizes the difference in the extraction reaction rates of the five alkali metal cations of lithium, sodium, potassium, rubidium, and cesium to achieve an unsatisfactory separation effect, the stripping stage can again utilize the difference in the stripping reaction rates of the five alkali metal cations of lithium, sodium, potassium, rubidium, and cesium to enhance their pairwise separation. By adjusting the process parameters, adjusting the number of the non-steady flow discrete extraction system or the non-steady flow discrete stripping system in series, or any combination of the non-steady flow discrete extraction system and the non-steady flow discrete stripping system, a short-process rapid separation of the five alkali metal cations of lithium, sodium, potassium, rubidium, and cesium can be achieved.

[0108] Compared with the prior art, the present invention has at least the following beneficial effects:

[0109] (1) The present invention is based on the difference in extraction reaction rates of five alkali metal cations, namely lithium, sodium, potassium, rubidium and cesium. Discrete organic extractant oil droplets or hollow oil droplets coated with bubbles are continuously sprayed into a mixed aqueous solution containing the five alkali metal cations or at least three of them. The water-oil two-phase countercurrent contact can achieve step-by-step extraction of the five alkali metal cations in the mixed aqueous solution and separation of them two by two. The five alkali metal cations are step-by-step discharged in the order of cesium > rubidium > potassium > sodium > lithium. The process is simple and the separation efficiency is high.

[0110] (2) The present invention is based on the difference in the stripping reaction rates of the five alkali metal cations of lithium, sodium, potassium, rubidium and cesium. A discrete droplet flow of hydrochloric acid or sulfuric acid aqueous solution is continuously sprayed into the extracted loaded organic phase containing the five alkali metal ions or at least three of them. The water-oil two phases are in countercurrent contact, which can realize the step-by-step stripping and elution of the five alkali metal cations in the loaded organic phase and separate them from each other. The five alkali metal cations are separated in steps in the order of lithium>sodium>potassium>rubidium>cesium. The process is simple and the separation efficiency is high.

[0111] (3) The present invention can achieve rapid separation of five alkali metal cations, lithium, sodium, potassium, rubidium, and cesium, or a mixed system of any three or more of them by adjusting process parameters, adjusting the number of series connections of the non-steady flow discrete extraction system or the non-steady flow discrete stripping system, or any combination of the non-steady flow discrete extraction system and the non-steady flow discrete stripping system. The device and process parameters can be flexibly adjusted, with high universality, and have achieved significant progress compared to the cumbersome multi-step separation and extraction of the prior art.

[0112] (4) The present invention is applicable to the mutual separation of five alkali metal cations of lithium, sodium, potassium, rubidium and cesium with similar properties, and is also applicable to the mutual separation of other similar elements of the same family or period with similar properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0113] Figure 1 This is a schematic diagram of the system structure for separating alkali metal ions by non-steady flow discrete extraction according to the present invention;

[0114] In the non-steady flow discrete extraction device, 1 is the oil phase overflow outlet; 2 is the hollow straight tube column; 6 is the oil inlet; 7 is the air inlet; 10 is the water phase outlet; 11 is the water phase inlet;

[0115] In the non-steady flow discrete extraction device, 37 is a periodic flow pump; 38 is a first liquid replenishing device; 39 is a first intermediate liquid storage device; 40 is a second liquid replenishing device; 41 is a first collecting device;

[0116] Figure 2 Schematic diagram of the structure of the non-steady flow discrete extraction device of the present invention;

[0117] Among them, 1 is the oil phase overflow outlet; 2 is the hollow straight pipe column; 3 is the oil distributor; 4 is the upper flange; 5 is the lower flange; 6 is the oil inlet; 7 is the air inlet; 8 is the oil distributor air chamber; 9 is the oil distributor oil chamber; 10 is the water phase outlet; 11 is the water phase inlet; 12 is the porous bubble breaking baffle;

[0118] Figure 3 This is a schematic diagram of the oil distributor structure of the non-steady flow discrete extraction device of the present invention;

[0119] Among them, 6 is the oil inlet; 7 is the air inlet; 8 is the oil distributor air chamber; 9 is the oil distributor oil chamber; 15 is the injection head;

[0120] FIG4 is a schematic diagram of the structure of a porous bubble-breaking baffle provided on the upper port of the hollow straight tube column of the non-steady flow discrete extraction device of the present invention, wherein FIG4(a) is a bottom view and FIG4(b) is a front view;

[0121] FIG5 is a schematic diagram of the structure of the oil distributor spray head of the unsteady flow discrete extraction device of the present invention, wherein FIG5(a) is a top view and FIG5(b) is a front view; 13 is the outer oil inlet pipe; 14 is the inner air inlet pipe;

[0122] Figure 6 This is a working principle diagram of a system for the non-steady flow discrete extraction and separation of alkali metal ions according to the present invention;

[0123] Among them, A is the overflowed loaded organic phase after extraction; B is the hollow oil droplet dispersed phase; C is the residual water phase; D is the pumped-in air; E is the pumped-in organic solution containing the extractant; F is the mixed organic solution containing the extractant; G is a pure organic solvent; H is a mixture of an organic extractant and an organic solvent; I is a pure organic extractant; J is a mixed aqueous solution containing alkali metal ions; and K is the loaded organic phase after polymerization.

[0124] Figure 7This is a five-stage series working principle diagram of a non-steady flow discrete extraction and separation system for alkali metal ions according to the present invention;

[0125] Figure 8 This is a schematic diagram of the system structure for separating alkali metal ions by non-steady flow discrete stripping according to the present invention;

[0126] Among them, in the non-steady flow discrete stripping device, 16 is the oil phase overflow outlet; 19 is the hollow straight tube column; 23 is the water phase outlet; 25 is the oil inlet; 26 is the water distributor;

[0127] In the non-steady flow discrete stripping system, 42 is a periodic variable frequency pulse pump; 43 is a third liquid replenishing device; 44 is a second intermediate liquid storage device; 45 is a fourth liquid replenishing device; 46 is a second collecting device;

[0128] Figure 9 Schematic diagram of the structure of the non-steady flow discrete stripping device of the present invention;

[0129] Among them, 16 is the oil phase overflow outlet; 17 is the upper flange; 18 is the lower flange; 19 is the hollow straight pipe column; 20 is the second porous water retaining plate; 21 is the upper flange; 22 is the lower flange; 23 is the water phase outlet; 24 is the water phase chamber; 25 is the oil inlet; 26 is the water distributor; 27 is the first porous water retaining plate; 28 is the oil phase chamber;

[0130] Figure 10 This is a schematic diagram of the water distributor structure of the non-steady flow discrete stripping device of the present invention;

[0131] Among them, 29 is the water inlet of the water distributor; 30 is the diversion cavity of the water distributor; 31 is the water spraying orifice plate of the water distributor; 32 is the water spraying pipe of the water distributor;

[0132] FIG11 is a schematic diagram of the structure of the water distributor guide chamber of the non-steady flow discrete stripping device of the present invention, wherein FIG11(a) is a bottom view, FIG11(b) is a top view, and FIG11(c) is a left view; 29 is the water inlet of the water distributor; 30 is the water distributor guide chamber; 31 is the water spray orifice plate of the water distributor;

[0133] Figure 12 This is a schematic diagram of the structure of the water distributor spray pipe of the non-steady flow discrete stripping device of the present invention;

[0134] Among them, 32 is the water distributor spray pipe; 33 is the coupling; 34 is the guide orifice plate; 35 is the spring shaft; 36 is the sieve plate;

[0135] Figure 13 This is a schematic diagram of the structure of the guide orifice plate provided inside the upper port of the water distributor spray pipe of the non-steady flow discrete stripping device of the present invention;

[0136] FIG14 is a schematic diagram of the structure of a sieve plate fixedly connected to the lower end of a spring shaft in a water distributor spray pipe of the non-steady flow discrete stripping device according to the present invention, wherein FIG14(a) is a top view and FIG14(b) is a front view;

[0137] FIG15 is a schematic diagram of the structure of a second porous water retaining plate provided at the lower end of the hollow straight tube column of the non-steady flow discrete stripping device according to the present invention, wherein FIG15(a) is a top view and FIG15(b) is a front view;

[0138] FIG16 is a schematic diagram of the structure of a first porous water retaining plate provided at the upper port of a hollow straight tube column of the non-steady flow discrete stripping device according to the present invention, wherein FIG16(a) is a bottom view and FIG16(b) is a front view;

[0139] Figure 17 This is a working principle diagram of a system for separating alkali metal ions by non-steady flow discrete stripping according to the present invention;

[0140] Among them, L is the organic phase after stripping; M is the stripping liquid droplets; N is the stripping raffinate; O is the loaded organic phase containing alkali metal ions; P is the pumped stripping liquid; Q is the mixed stripping liquid; R is pure water; S is a mixture of acid and pure water; T is pure acid.

[0141] Figure 18 This is a five-stage series working principle diagram of a non-steady-flow discrete stripping system for separating alkali metal ions according to the present invention;

[0142] Figure 19 This is a schematic diagram of the working principle of a system for separating alkali metal ions by non-steady flow discrete extraction and a system for separating alkali metal ions by non-steady flow discrete stripping in series according to the present invention. DETAILED DESCRIPTION

[0143] To better illustrate the present invention and facilitate understanding of the technical solutions of the present invention, typical but non-limiting embodiments of the present invention are as follows. Those skilled in the art should understand that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0144] Example 1

[0145] A system for the separation of alkali metal ions by non-steady flow discrete extraction, such as Figure 1 As shown, it includes a non-steady flow discrete extraction device, a periodic flow pump 37, a first intermediate liquid storage device 39, a first liquid replenishing device 38, a second liquid replenishing device 40 and a first collecting device 41. Figure 2As shown, the non-steady flow discrete extraction device is composed of a hollow straight tube column 2 and an oil distributor 3. The length of the hollow straight tube column 2 is 20.0 cm and the inner diameter is 1.0 cm. The hollow straight tube column 2 is provided with an oil phase overflow outlet 1 located on one side of the top tube wall, a water phase inlet 11 located on the other side of the upper tube wall and lower than the oil phase overflow outlet, and a water phase outlet 10 located on one side of the lower tube wall. The oil distributor 3 is located at the bottom end of the hollow straight tube column 2 and is connected to the hollow straight tube column 2 by an upper flange 4 and a lower flange 5. Figure 3 As shown, the oil distributor 3 consists of an injector head 15, an oil distributor oil chamber 9, and an oil distributor air chamber 8. As shown in Figure 5, the oil distributor injector head 15 is composed of a set of hollow straight tubes nested inside and outside. The inner tube 14 is an air inlet pipe with an inner diameter of 0.05 mm, which is connected to the oil distributor air chamber 8. The outer tube 13 is an oil inlet pipe with an inner diameter of 0.6 mm, and the narrow gap between the inner wall of the outer oil inlet pipe 13 and the outer wall of the inner air inlet pipe 14 is connected to the oil distributor oil chamber 9. The nozzle of the oil distributor injector head 15 is directed toward the top of the hollow straight tube column 2. The lower end of the oil distributor air chamber 8 is provided with an air inlet 7, which is connected to the oil distributor air chamber 8. The side wall of the oil distributor oil chamber 9 is provided with an oil inlet 6, which is connected to the oil distributor oil chamber 9. A porous bubble-breaking baffle 12 is provided at the upper end of the hollow straight tube column 2, the structure of which is shown in Figure 4. The porous bubble-breaking baffle 12 is located below the oil phase overflow outlet 1 at the top of the hollow straight tube column 2 and above the water phase inlet 11 on the upper tube wall. A contraction trumpet-shaped channel is provided inside the porous bubble-breaking plate 12. The periodic flow pump 37 is a peristaltic pump whose pumping flow rate changes periodically. The first intermediate liquid storage device 39 is a liquid storage tank with stirring, in which a stirring device is provided. The first liquid replenishing device 38 and the second liquid replenishing device 40 are liquid storage tanks. The outlet of the first intermediate liquid storage device 39 is connected to the inlet of the periodic flow pump 37. The inlet of the first intermediate liquid storage device 39 is respectively connected to the outlets of the first liquid replenishing device 38 and the second liquid replenishing device 40. The outlet of the periodic flow pump 37 is connected to the oil inlet 6 on the side wall of the oil distributor oil chamber of the non-steady flow discrete extraction device. The first collection device 41 is an automatic stepping collector, and the inlet of the automatic stepping collector 41 is connected to the oil phase overflow outlet 1 at the top of the hollow straight tube column 2.

[0146] A method for extracting and separating a mixed aqueous solution containing five ions of lithium, sodium, potassium, rubidium and cesium using the above system, such as Figure 6As shown. A is the extracted loaded organic phase flowing out of the oil phase overflow outlet at the top of the hollow straight tube column of the non-steady flow discrete extraction device; B is the dispersed phase of hollow oil droplets containing extractant or air bubbles sprayed out of the nozzle of the oil distributor spray head of the non-steady flow discrete extraction device, and the flow rate of the droplet flow shows a non-steady periodic change; C is the residual water phase flowing out of the water phase outlet at the bottom of the hollow straight tube column of the non-steady flow discrete extraction device; D is the air pumped into the air inlet at the bottom end of the non-steady flow discrete extraction device; E is the organic solution containing extractant pumped into the oil inlet of the oil chamber of the oil distributor of the non-steady flow discrete extraction device; F is the first intermediate liquid storage The extractant-containing organic solution obtained by mixing in the device, wherein the concentration of the organic extractant t-BAMBP continuously increases; G is the pure organic solvent pumped out by the first liquid replenishing device; H is the organic extractant t-BAMBP and organic solvent mixture mixed in the first intermediate liquid storage device; I is the pure organic extractant t-BAMBP pumped out by the second liquid replenishing device; J is the mixed aqueous solution containing alkali metal ions pumped into the aqueous phase inlet at the upper part of the hollow straight tube column of the non-steady flow discrete extraction device; K is the extracted loaded organic phase obtained after bubble breaking and aggregation at the porous bubble breaking baffle at the top of the non-steady flow discrete extraction device. The steps are as follows:

[0147] A mixed aqueous solution with a pH of 12.5 and containing lithium, sodium, potassium, rubidium, and cesium ions was introduced into the upper aqueous phase inlet hollow straight tubular column of the unsteady flow discrete extraction device in the aforementioned unsteady flow discrete extraction system for separating alkali metal ions. The total concentration of alkali metal ions in the mixed aqueous solution was 5 g / L. The mixed aqueous solution was then kept stationary within the hollow straight tubular column. Kerosene was pumped from the first liquid replenishment device into the agitated first intermediate liquid storage device. The outlet valve of the first liquid replenishment device was closed, and t-BAMBP was continuously pumped from the second liquid replenishment device into the agitated first intermediate liquid storage device. Simultaneously, a periodic flow pump was activated, with a set flow rate increase range and cycle value. The organic solution containing the extractant obtained from the mixing in the first intermediate liquid storage device was pumped into the oil chamber of the oil distributor from the lower oil phase inlet of the unsteady flow discrete extraction device. The volume percentage of t-BAMBP in the organic solution containing the extractant was continuously increased from 1% to 30% at a rate of 0.5% per minute. The volumetric flow rate of the extractant-containing organic solution ejected from the nozzle of the oil distributor spray head increases periodically from 0.5 mL / min to 5.0 mL / min, with a cycle of 10 minutes and a rate of increase of 0.5 mL / min per cycle. The volumetric flow rate of air pumped into the bottom inlet of the non-steady flow discrete extraction device is 0 mL / min. The extractant-containing oil droplets ejected from the nozzle of the oil distributor spray head are in a discrete dispersed phase state, and the number of oil droplets varies with the periodic flow rate of the periodic pump. The concentration of the organic extractant in the oil droplets varies with the concentration of the extractant in the first intermediate liquid storage device. The extractant-containing oil droplets, moving in a discrete flow, come into countercurrent contact with the mixed aqueous solution containing alkali metal ions contained in the device from bottom to top, ultimately coalescing at the porous bubble-breaking baffle at the top of the non-steady flow discrete extraction device before flowing out of the top oil phase overflow outlet. An automatic stepping collector collects the loaded organic phase flowing out of the oil phase overflow outlet at the top of the non-steady flow discrete extraction device. The automatic stepping collector rotates at a constant speed for 5 minutes, i.e., it rotates once every 5 minutes. The loaded organic phases extracted with different alkali metal ions in different time periods are mixed with a 1.0 mol / L sulfuric acid aqueous solution at a volume ratio of 5:1 for 0.1 hour for back extraction. After the oil and water are allowed to stand and separate, the lower aqueous phases are collected and the alkali metal ion concentrations therein are detected. A graph is plotted with the cumulative volume of the organic solution collected by the automatic stepping collector as the horizontal axis and the concentrations of various alkali metal ions in the lower aqueous phase obtained after back extraction of the organic solution collected each time as the vertical axis.The results showed that the main component of the loaded organic phase collected by the automatic collector from 0 to 10 minutes was a cesium ion complex, with a separation factor of 102 between cesium and rubidium ions, and a separation factor greater than 550 between cesium and other coexisting alkali metal ions. The main component of the loaded organic phase from 11 to 20 minutes was a rubidium ion complex, with a separation factor of 663 between rubidium and potassium ions, and a separation factor greater than 12,000 between rubidium and other coexisting alkali metal ions. The main component of the loaded organic phase from 21 to 35 minutes was a potassium ion complex, with a separation factor of 12,100 between potassium and sodium ions, and a separation factor greater than 30,000 between potassium and other coexisting alkali metal ions. The main component of the loaded organic phase from 36 to 60 minutes was a sodium ion complex, with a separation factor of 51,320 between sodium and lithium ions. The main component of the loaded organic phase collected from 61 to 100 minutes was a lithium ion complex. Excellent separation of the five ions of cesium, rubidium, potassium, sodium, and lithium was achieved.

[0148] Example 2

[0149] A mixed aqueous solution with an alkali concentration of 1.0 mol / L and containing five ions, lithium, sodium, potassium, rubidium, and cesium, was pumped from the upper aqueous phase inlet of a non-steady flow discrete extraction device in a non-steady flow discrete extraction system for separating alkali metal ions into a hollow straight tubular column with a length of 100.0 cm and an inner diameter of 10.0 cm. The alkali metal ion mixed aqueous solution was pumped at a rate of 5.0 mL / min. The total alkali metal ion concentration was 2 g / L. Next, xylene was pumped from the first liquid replenishment device into the first intermediate liquid storage device with stirring. The outlet valve of the first liquid replenishment device was closed, and t-BAMBP was continuously pumped from the second liquid replenishment device into the first intermediate liquid storage device with stirring. Simultaneously, a periodic flow pump was activated, with a set periodic flow rate increase range and period value. The organic solution containing the extractant, obtained after mixing in the first intermediate liquid storage device, was pumped from the oil phase inlet at the lower portion of the non-steady flow discrete extraction device into the oil chamber of the oil distributor. In the organic solution containing the extractant, the volume percentage of t-BAMBP increases continuously from 1% to 30% at a rate of 3% per minute. The volume flow rate of the organic solution containing the extractant ejected from the nozzle of the oil distributor spray head increases periodically and continuously from 0.5 mL / min to 3.0 mL / min, with a cycle value of one cycle per minute, and the rate of increase of the flow rate in each cycle is 3.0 mL per minute. Then, air is pumped into the air inlet at the bottom end of the non-steady flow discrete extraction device at a volume flow rate of 3.0 mL / min. The inner tube of the oil distributor spray head has an inner diameter of 0.5 mm and an inner diameter of the outer tube has an inner diameter of 1.0 mm. The hollow oil droplets encapsulating the bubbles ejected from the nozzle of the oil distributor spray head are in a discrete dispersed phase state, and the number of oil droplets varies with the periodic change of the periodic flow pump. The concentration of the organic extractant in the oil droplets varies with the concentration of the extractant in the first intermediate liquid storage device. Hollow oil droplets encapsulating bubbles in a discrete flow flow come into countercurrent contact with the alkali metal ion-containing aqueous solution contained within the apparatus. The bubbles eventually break and coalesce at the porous bubble-breaking baffle at the top of the non-steady-flow discrete extraction device, flowing out of the top oil phase overflow outlet. An automatic stepping collector collects the loaded organic phase flowing out of the oil phase overflow outlet at the top of the non-steady-flow discrete extraction device. The automatic stepping collector rotates at a constant speed every 10 minutes, rotating once every 10 minutes. The loaded organic phases, collected at different time intervals and containing different alkali metal ions, are then mixed with 2.0 mol / L hydrochloric acid or sulfuric acid aqueous solutions at a volume ratio of 10:1 for 2 hours for stripping. After the oil and water phases are allowed to separate, the lower aqueous phases are collected and the alkali metal ion concentrations are determined. A graph is plotted with the cumulative volume of the organic solution collected by the automatic stepping collector as the horizontal axis and the concentrations of various alkali metal ions in the lower aqueous phase after stripping of each collected organic solution as the vertical axis.The results showed that the main component of the loaded organic phase collected by the automatic collector from 0 to 10 minutes was a cesium ion complex, with a separation factor of 205 between cesium and rubidium ions and a separation factor greater than 800 between cesium and other coexisting alkali metal ions. The main component of the loaded organic phase from 11 to 20 minutes was a rubidium ion complex, with a separation factor of 933 between rubidium and potassium ions and a separation factor greater than 13,000 between rubidium and other coexisting alkali metal ions. The main component of the loaded organic phase from 21 to 40 minutes was a potassium ion complex, with a separation factor of 14,050 between potassium and sodium ions and a separation factor greater than 31,000 between potassium and other coexisting alkali metal ions. The main component of the loaded organic phase from 41 to 70 minutes was a sodium ion complex, with a separation factor of 64,710 between sodium and lithium ions. The main component of the loaded organic phase collected from 71 to 120 minutes was a lithium ion complex. Excellent separation of the five ions of cesium, rubidium, potassium, sodium, and lithium was achieved.

[0150] Example 3

[0151] A mixed aqueous solution with an alkali concentration of 1.0 mol / L and containing sodium, potassium, rubidium, and cesium ions was pumped from the upper aqueous phase inlet of a non-steady flow discrete extraction device in a non-steady flow discrete extraction system for separating alkali metal ions into a hollow straight tubular column with a length of 100.0 cm and an inner diameter of 10.0 cm. The alkali metal ion mixed aqueous solution was pumped at a rate of 20.0 mL / min. The total alkali metal ion concentration was 1 g / L. Next, xylene was pumped from the first rehydration device into the first intermediate liquid storage device with stirring. The outlet valve of the first rehydration device was closed, and t-BAMBP was continuously pumped from the second rehydration device into the first intermediate liquid storage device with stirring. Simultaneously, a periodic flow pump was activated, with a set periodic flow rate increase range and period value. The organic solution containing the extractant, obtained after mixing in the first intermediate liquid storage device, was pumped from the oil phase inlet at the lower portion of the non-steady flow discrete extraction device into the oil chamber of the oil distributor. The volume percentage of t-BAMBP in the extractant-containing organic solution increases continuously from 1% to 30% at a rate of 2% per minute. The volume flow rate of the extractant-containing organic solution ejected from the nozzle of the oil distributor spray head increases continuously and periodically from 0.5 mL / min to 5.0 mL / min, with a cycle value of one cycle per minute and a rate of increase of 5.0 mL per minute within each cycle. Air is then pumped into the bottom air inlet of the non-steady flow discrete extraction device at a volume flow rate of 0.5 mL / min. The inner tube of the oil distributor spray head has an inner diameter of 0.5 mm and an outer tube has an inner diameter of 1.0 mm. The hollow oil droplets encapsulating the bubbles ejected from the nozzle of the oil distributor spray head are in a discrete dispersed phase state, and the number of oil droplets varies with the periodic changes of the periodic flow pump. The concentration of the organic extractant in the oil droplets varies with the concentration of the extractant in the first intermediate liquid storage device. Hollow oil droplets encapsulating bubbles in a discrete flow flow come into countercurrent contact with the alkali metal ion-containing aqueous solution contained within the device. The bubbles eventually break and coalesce at the porous bubble-breaking baffle at the top of the non-steady-flow discrete extraction device, flowing out of the top oil phase overflow outlet. An automatic stepping collector collects the loaded organic phase flowing out of the oil phase overflow outlet at the top of the non-steady-flow discrete extraction device. The automatic stepping collector rotates at a constant speed every 40 minutes, rotating once every 40 minutes. The loaded organic phases, collected at different time intervals and containing different alkali metal ions, are mixed with a 0.1 mol / L aqueous sulfuric acid solution at a volume ratio of 1:1 for 1 hour for stripping. After the oil and water phases are allowed to separate, the lower aqueous phases are collected and the alkali metal ion concentrations are determined. A graph is plotted with the cumulative volume of the organic solution collected by the automatic stepping collector as the horizontal axis and the concentrations of various alkali metal ions in the lower aqueous phase after stripping of each collected organic solution as the vertical axis.The results showed that the main component of the loaded organic phase collected by the automatic collector from 0 to 40 minutes was a cesium ion extractant, with a separation factor of 188 between cesium and rubidium ions, and a separation factor greater than 920 between cesium and other coexisting alkali metal ions. The main component of the loaded organic phase from 41 to 80 minutes was a rubidium ion extractant, with a separation factor of 946 between rubidium and potassium ions, and a separation factor greater than 10,000 between rubidium and other coexisting alkali metal ions. The main component of the loaded organic phase from 81 to 160 minutes was a potassium ion extractant, with a separation factor of 14,100 between potassium and sodium ions. The main component of the loaded organic phase from 161 to 240 minutes was a sodium ion extractant. Excellent separation of the four ions of cesium, rubidium, potassium, and sodium was achieved.

[0152] Example 4

[0153] A system for the separation of alkali metal ions by non-steady flow discrete extraction, such as Figure 7 As shown, the system comprises five serially connected non-steady flow discrete extraction systems for separating alkali metal ions. The hollow straight tubular column dimensions of each non-steady flow discrete extraction device are 60.0 cm × 5.0 cm (length × inner diameter). The inner tube inner diameter of the oil distributor nozzle is 0.3 mm, and the outer tube inner diameter is 0.8 mm. The lower aqueous phase outlet of the hollow straight tubular column of the upstream non-steady flow discrete extraction device is connected to the upper aqueous phase inlet of the hollow straight tubular column of the downstream non-steady flow discrete extraction device. The raffinate aqueous phase flowing from the lower aqueous phase outlet of the upstream device is continuously pumped into the upper aqueous phase inlet of the downstream device. The oil distributor of each non-steady flow discrete extraction device is independently pumped with an organic solution containing an extractant, and each non-steady flow discrete extraction device has a separate air supply at the bottom. The extracted loaded organic phase flowing from the oil phase overflow port at the top of the hollow straight tubular column of each non-steady flow discrete extraction device is collected by an automatic stepping collector.

[0154] A method for extracting and separating a mixed aqueous solution containing five ions of lithium, sodium, potassium, rubidium and cesium using the above system, such as Figure 7 As shown, the steps are as follows:

[0155] A mixed aqueous solution with an alkali concentration of 1.0 mol / L and containing five ions, lithium, sodium, potassium, rubidium, and cesium, was pumped into a hollow straight tubular column from the upper aqueous phase inlet of the unsteady flow discrete extraction unit in the first-stage unsteady flow discrete extraction system for separating alkali metal ions. The pumping rate of the mixed aqueous solution containing alkali metal ions was 100.0 mL / min. The total concentration of alkali metal ions was 0.1 to 5 g / L. Kerosene was then pumped from the first liquid replenishment unit into the first intermediate liquid storage unit with stirring. The outlet valve of the first liquid replenishment unit was closed, and t-BAMBP was continuously pumped from the second liquid replenishment unit into the first intermediate liquid storage unit with stirring. Simultaneously, a periodic flow pump was activated, with a set periodic flow rate increase range and period value. The organic solution containing the extractant, obtained after mixing in the first intermediate liquid storage unit, was pumped into the oil chamber of the oil distributor from the lower oil phase inlet of the first-stage unsteady flow discrete extraction unit. The volume percentage of t-BAMBP in the extractant-containing organic solution is continuously increased from 1% to 30% at a rate of 1% per minute. The volume flow rate of the extractant-containing organic solution ejected from the nozzle of the oil distributor spray head is periodically and continuously increased from 0.5 mL / min to 5.0 mL / min, with a cycle value of one cycle every 10 minutes and a rate of increase of 0.5 mL per minute within each cycle. Air is then pumped into the bottom air inlet of the first-stage non-steady flow discrete extraction device at a volume flow rate of 5.0 mL / min. The inner tube of the oil distributor spray head has an inner diameter of 0.05 mm and an outer tube has an inner diameter of 0.6 mm. The hollow oil droplets encapsulating the bubbles ejected from the nozzle of the oil distributor spray head are in a discrete dispersed phase state, and the number of oil droplets varies with the periodic flow rate of the periodic pump. The concentration of the organic extractant in the oil droplets varies with the concentration of the extractant in the first intermediate liquid storage device. Hollow oil droplets encapsulating bubbles in a discrete flow flow come into countercurrent contact with the alkali metal ion-containing aqueous solution contained within the device from bottom to top. The bubbles eventually break and coalesce at the porous bubble-breaking baffle at the top of the non-steady flow discrete extraction device before flowing out of the top oil phase overflow outlet. The raffinate aqueous phase flowing from the lower aqueous phase outlet of the first-stage non-steady flow discrete extraction device is continuously pumped into the upper aqueous phase inlet of the second-stage non-steady flow discrete extraction device at a volume flow rate of 100.0 mL / min. The second-stage non-steady flow discrete extraction device performs the same operations as the first-stage non-steady flow discrete extraction device. The volume percentage of t-BAMBP pumped into the lower oil phase inlet of the second-stage non-steady flow discrete extraction device increases continuously from 1% to 30% at a rate of 1.0% per minute. The volume flow rate of the organic solution containing the extractant sprayed from the nozzle of the oil distributor nozzle at the bottom end of the second-stage unsteady flow discrete extraction device remains equal to the volume flow rate of the organic solution containing the extractant sprayed from the nozzle of the oil distributor nozzle at the bottom end of the first-stage unsteady flow discrete extraction device.The volumetric flow rate of the extractant-containing organic solution ejected from the oil distributor nozzle was periodically increased from 0.5 mL / min to 5.0 mL / min, with a cycle of 10 minutes and a rate of increase of 0.5 mL / min within each cycle. The third, fourth, and fifth stage unsteady flow discrete extraction devices performed the same operation as described above. The volumetric flow rate of the alkali metal ion-containing aqueous solution pumped into the upper aqueous phase inlet of each unsteady flow discrete extraction device was controlled at 100.0 mL / min. The volumetric percentage of t-BAMBP in the extractant-containing organic solution pumped into the lower oil phase inlet of each stage of the unsteady flow discrete extraction device was continuously increased from 1% to 30% at a rate of 1.5% / min (third stage), 2.0% / min (fourth stage), and 3.0% / min (fifth stage). The extracted loaded organic phase flowing out of the oil phase overflow port at the top of each stage of the unsteady flow discrete extraction device was collected using an automatic step collector. The automatic stepping collector rotates at a constant speed every 5 minutes, meaning it rotates once every 5 minutes. The loaded organic phases collected by each stage of the non-steady-flow discrete extraction device were mixed with a 2.0 mol / L aqueous hydrochloric acid solution at a volume ratio of 5:1 for 0.1 hour for back extraction. After the oil and water were allowed to stand for phase separation, the lower aqueous phases were collected and the alkali metal ion concentrations therein were determined. A graph was plotted with the cumulative volume of the organic solution collected by the automatic stepping collector as the horizontal axis and the concentrations of various alkali metal ions in the lower aqueous phase obtained after back extraction of each collected organic solution as the vertical axis. The results showed that the main component of the loaded organic phase exiting the upper oil phase outlet of the first-stage unsteady flow discrete extraction device was a cesium ion complex, with a separation coefficient greater than 200 for cesium and other coexisting alkali metal ions. The main component of the loaded organic phase exiting the upper oil phase outlet of the second-stage unsteady flow discrete extraction device was a rubidium ion complex, with a separation coefficient greater than 910 for rubidium and other coexisting alkali metal ions. The main component of the loaded organic phase exiting the upper oil phase outlet of the third-stage unsteady flow discrete extraction device was a potassium ion complex, with a separation coefficient greater than 11,000 for potassium and other coexisting alkali metal ions. The main component of the loaded organic phase exiting the upper oil phase outlet of the fourth-stage unsteady flow discrete extraction device was a sodium ion complex, with a separation coefficient greater than 35,000 for sodium and lithium ions. The main component of the loaded organic phase exiting the upper oil phase outlet of the fifth-stage unsteady flow discrete extraction device was a lithium ion complex. Excellent separation of the five ions, cesium, rubidium, potassium, sodium, and lithium, was achieved.

[0156] Example 5

[0157] Three unsteady-flow discrete extraction systems for alkali metal ion separation were connected in series. The hollow straight tubular column dimensions of each system's unsteady-flow discrete extraction device were 80.0 cm × 7.0 cm (length × inner diameter). The inner tube inner diameter of the oil distributor nozzle was 0.2 mm, and the outer tube inner diameter was 0.6 mm. The lower aqueous phase outlet of the hollow straight tubular column of the upstream unsteady-flow discrete extraction device was connected to the upper aqueous phase inlet of the hollow straight tubular column of the downstream unsteady-flow discrete extraction device. The raffinate aqueous phase flowing from the lower aqueous phase outlet of the upstream device was continuously pumped into the upper aqueous phase inlet of the downstream device. The oil distributor of each unsteady-flow discrete extraction device was independently pumped with an organic solution containing an extractant, and each unsteady-flow discrete extraction device had a separate air supply at the bottom. The extracted loaded organic phase flowing from the oil phase overflow port at the top of the hollow straight tubular column of each unsteady-flow discrete extraction device was collected by an automatic stepping collector.

[0158] The above system is used to extract and separate a mixed aqueous solution of rubidium, cesium, and potassium ions. The steps are as follows:

[0159] A mixed aqueous solution containing rubidium, cesium, and potassium ions with a 1.0 mol / L alkali concentration was pumped from the upper aqueous phase inlet of the unsteady flow discrete extraction device in the first-stage unsteady flow discrete extraction system for separating alkali metal ions into a hollow straight tubular column. The pumping rate of the mixed aqueous solution containing alkali metal ions was 1.0 mL / min. The total concentration of alkali metal ions was 1 g / L. Kerosene was then pumped from the first rehydration device into the first intermediate liquid storage device with stirring. The outlet valve of the first rehydration device was closed, and t-BAMBP was continuously pumped from the second rehydration device into the first intermediate liquid storage device with stirring. At the same time, a periodic flow pump was activated, and the periodic increase range and cycle value of the pumped flow rate were set. The organic solution containing the extractant, obtained after mixing in the first intermediate liquid storage device, was pumped into the oil chamber of the oil distributor through the oil phase inlet at the bottom of the unsteady flow discrete extraction device. The volume percentage of t-BAMBP in the organic solution containing the extractant was continuously increased from 1% to 30% at a rate of 3% per minute. The volume flow rate of the organic solution containing the extractant ejected from the nozzle of the oil distributor nozzle was continuously increased from 0.5 mL / min to 5.0 mL / min at a cycle value of one cycle every 5 minutes, and the flow rate increased by 1.0 mL per minute within each cycle. Air was then pumped into the air inlet at the bottom end of the unsteady flow discrete extraction device at a volume flow rate of 2.5 mL / min. The hollow oil droplets encapsulating the bubbles ejected from the oil distributor nozzle are in a discrete dispersed phase, and the number of oil droplets varies with the periodic flow rate of the periodic pump. The concentration of the organic extractant in the oil droplets varies with the concentration of the extractant in the first intermediate liquid storage device. The hollow oil droplets encapsulating the bubbles, moving in a discrete flow, come into countercurrent contact with the mixed aqueous solution containing alkali metal ions contained within the device from bottom to top, ultimately breaking and coalescing at the top porous bubble breaking baffle of the unsteady flow discrete extraction device before flowing out of the top oil phase overflow outlet. The raffinate aqueous phase flowing from the lower aqueous phase outlet of the unsteady flow discrete extraction device of the first stage is continuously pumped into the upper aqueous phase inlet of the unsteady flow discrete extraction device of the second stage at a volumetric flow rate of 1.0 mL / min. The volume percentage of t-BAMBP pumped into the lower oil phase inlet of the unsteady flow discrete extraction device of the second stage increases continuously from 1% to 30% at a rate of 3% per minute. The volumetric flow rate of the extractant-containing organic solution ejected from the nozzle of the oil distributor nozzle at the bottom of the second-stage unsteady-flow discrete extraction device continuously increases periodically from 0.5 mL / min to 5.0 mL / min, with a cycle value of one cycle every three minutes, and the flow rate increasing at a rate of 1.5 mL per minute within each cycle. The raffinate aqueous phase flowing from the lower aqueous phase outlet of the unsteady-flow discrete extraction device of the second-stage system is continuously pumped into the upper aqueous phase inlet of the unsteady-flow discrete extraction device of the third-stage system. The volumetric flow rate of the mixed aqueous solution containing alkali metal ions pumped into the upper aqueous phase inlet of the unsteady-flow discrete extraction device of the third-stage system is 1.0 mL / min.The volume percentage of t-BAMBP pumped into the oil phase inlet at the bottom of the third-stage unsteady flow discrete extraction unit was continuously increased from 1% to 30% at a rate of 6% per minute. The volume flow rate of the extractant-containing organic solution ejected from the oil distributor nozzle at the bottom of the third-stage unsteady flow discrete extraction unit was periodically increased from 0.5 mL / min to 5.0 mL / min, with a cycle of one cycle every two minutes and a rate of increase of 2.5 mL per minute within each cycle. Other operations of the second and third-stage unsteady flow discrete extraction units were identical to those of the first-stage unsteady flow discrete extraction unit. The loaded organic phase flowing from the oil phase overflow at the top of each unsteady flow discrete extraction unit was collected by an automatic stepping collector. The automatic stepping collector rotated at a constant speed for a 5-minute interval, i.e., once every 5 minutes. The loaded organic phase collected from each stage of the unsteady flow discrete extraction unit was mixed with a 2.0 mol / L aqueous sulfuric acid solution at a volume ratio of 10:1 for 0.5 h for stripping. After the oil and water were allowed to stand and separate, the lower aqueous phase was collected and the alkali metal ion concentrations were measured. A graph was plotted with the cumulative volume of organic solution collected by the automatic stepping collector as the horizontal axis and the concentrations of various alkali metal ions in the lower aqueous phase obtained after stripping of each collected organic solution as the vertical axis. The results showed that the primary component of the loaded organic phase exiting the upper oil phase outlet of the first-stage unsteady flow discrete extraction device was a cesium ion extractant, with a separation factor greater than 300 between cesium and other coexisting alkali metal ions. The primary component of the loaded organic phase exiting the upper oil phase outlet of the second-stage unsteady flow discrete extraction device was a rubidium ion extractant, with a separation factor greater than 1000 between rubidium and potassium ions. The primary component of the loaded organic phase exiting the upper oil phase outlet of the third-stage unsteady flow discrete extraction device was a potassium ion extractant. Excellent separation of cesium, rubidium, and potassium ions was achieved.

[0160] Example 6

[0161] A system for separating alkali metal ions by non-steady flow discrete stripping, such as Figure 8 As shown, it includes a non-steady flow discrete stripping device, a periodic variable frequency pulse pump 42, a second intermediate liquid storage device 44, a third liquid replenishing device 43, a fourth liquid replenishing device 45 and a second collecting device 46. Figure 9As shown, the non-steady flow discrete stripping device is composed of a hollow straight tube column 19, an oil phase chamber 28, a water phase chamber 24 and a water distributor 26. The length of the hollow straight tube column 19 is 30.0 cm and the inner diameter is 3.0 cm. An oil inlet 25 is provided on one side of the lower tube wall of the hollow straight tube column 19. The oil phase chamber 28 is located at the top of the hollow straight tube column 19 and is connected to the hollow straight tube column 19 by an upper flange 17 and a lower flange 18. The water phase chamber 24 is located at the bottom of the hollow straight tube column 19 and is connected to the hollow straight tube column 19 by an upper flange 21 and a lower flange 22. The oil phase chamber 28 is provided with an oil phase overflow outlet 16 located on one side of the top tube wall. The water phase chamber 24 is provided with a water phase outlet 23 located on one side of the bottom tube wall. The water distributor 26 is located on the upper part of the hollow straight tube column 19 and below the lower flange 18 connecting the oil phase chamber 28 and the hollow straight tube column 19. As shown Figure 10 As shown in Figure 11, the water distributor 26 includes a water inlet 29, a flow guide chamber 30, a water spray orifice plate 31, and a water spray pipe 32. The upper end of the water spray pipe 32 is connected to the flow guide chamber 30 of the water distributor and is welded to the orifice of the water spray orifice plate 31 in a one-to-one correspondence. The inner diameter of the water spray pipe 32 is 2.0 mm and the length is 10.0 mm. Figure 12 and Figure 13As shown, the upper end of the water spray pipe 32 is internally provided with a guide orifice plate 34, which is welded to the inner wall of the upper end of the water spray pipe 32. A spring shaft 35 is installed within the water spray pipe 32. The upper end of the spring shaft 35 is connected to the center hole of the guide orifice plate 34 via a coupling 33. The lower end of the spring shaft 35 is provided with three sieve plates 36 arranged in an upper and lower layer. The center holes of the sieve plates 36 are connected to the lower end of the spring shaft 35 via a coupling 33. The diameter of the sieve plates 36 is 1.95 mm. The spring shaft 35 within the water spray pipe 32 can freely extend and retract relative to the inner wall of the water spray pipe 32 and along the length of the water spray pipe 32. This upward and downward movement of the spring shaft 35 drives one or more sieve plates 36 fixed at the lower end of the spring shaft 35 to move up and down relative to the inner wall of the water spray pipe 32. The sieve plate 36 fixed at the lower end of the spring shaft 35 is internally provided with upper and lower contracting trumpet-shaped channels, the structure of which is shown in Figure 14. The lower end nozzle of the water spray pipe 32 is directed toward the bottom end of the hollow straight pipe column 19. A first porous water baffle 27 is provided at the upper end of the hollow straight pipe column 19. The first porous water baffle 27 is located below the upper flange 18 and above the water distributor 26. A second porous water baffle 20 is provided at the lower end of the hollow straight pipe column 19. The second porous water baffle 20 is located above the lower flange 21 and below the oil inlet 25 on the lower side wall of the hollow straight pipe column 19. As shown in Figures 15 and 16, contracting trumpet-shaped channels are provided inside the first and second porous water baffles 27 and 20. The periodic variable frequency pulse pump 42 is a plunger pump with a periodically changing pulse frequency. The second intermediate liquid storage device 44 is a liquid storage tank with stirring, in which a stirring device is provided. The third liquid replenishing device 43 and the fourth liquid replenishing device 45 are liquid storage tanks. The outlet of the second intermediate liquid storage device 44 is connected to the inlet of the periodic variable frequency pulse pump 42. The inlet of the second intermediate liquid storage device 44 is connected to the outlets of the third liquid replenishing device 43 and the fourth liquid replenishing device 45 respectively. The outlet of the periodic variable frequency pulse pump 42 is connected to the water inlet 29 of the water distributor of the non-steady flow discrete stripping device. The second collection device 46 is an automatic stepping collector, and the inlet of the automatic stepping collector 46 is connected to the water phase outlet 23 of the water phase chamber at the lower end of the hollow straight tube column 19.

[0162] A method for stripping and separating an organic phase loaded with five alkali metal ions, namely lithium, sodium, potassium, rubidium and cesium, by using the above system, such as Figure 17As shown. Wherein L is the stripped organic phase overflowing from the outlet of the oil phase chamber at the top of the non-steady flow discrete stripping device; M is the stripping liquid droplets sprayed from the nozzle of the water distributor of the non-steady flow discrete stripping device, and the flow rate of the droplet flow shows a non-steady periodic change; N is the stripping residual liquid flowing out of the water phase outlet at the bottom of the water phase chamber of the non-steady flow discrete stripping device; O is the alkali metal ion-loaded organic phase pumped into the lower oil phase inlet of the non-steady flow discrete stripping device, that is, the loaded organic phase obtained after the mixed aqueous solution containing alkali metal ions is extracted by the extractant-containing organic solution of the present invention; P is the stripping liquid pumped into the water inlet of the upper water distributor of the non-steady flow discrete stripping device; Q is the stripping liquid obtained by mixing in the second intermediate liquid storage device, wherein the concentration of hydrochloric acid or sulfuric acid continuously increases; R is the pure water pumped out by the third liquid replenishing device; S is the mixture of hydrochloric acid or sulfuric acid and pure water mixed in the second intermediate liquid storage device; T is the pure hydrochloric acid or sulfuric acid pumped out by the fourth liquid replenishing device. The steps are as follows:

[0163] A 30% by volume t-BAMBP kerosene solution was mixed with a mixed aqueous solution containing lithium, sodium, potassium, rubidium, and cesium ions in a 1:10 volume ratio for 2 hours. After oil-water separation, the upper organic phase was collected to obtain an alkali metal ion-loaded organic phase. The total concentration of alkali metal ions in the loaded organic phase was 5 g / L. This loaded organic phase, containing lithium, sodium, potassium, rubidium, and cesium ions, was pumped from the lower oil phase inlet of a non-steady-flow discrete stripping unit in a system for separating alkali metal ions by non-steady-flow discrete stripping into a hollow straight tubular column. The alkali metal ion-loaded organic phase was then kept stationary within the hollow straight tubular column. Pure water was pumped from the third rehydration unit into a stirred second intermediate liquid storage unit. The outlet valve of the third rehydration unit was then closed, and commercially available sulfuric acid was continuously pumped from the fourth rehydration unit into the stirred second intermediate liquid storage unit. At the same time, a periodic variable-frequency pulse pump is turned on, and the pulse frequency is set to a periodic increase range and a period value. The mixed aqueous sulfuric acid solution in the second intermediate liquid storage device is pumped from the water inlet of the upper water distributor of the non-steady-flow discrete stripping device into the second intermediate liquid storage device. The molar concentration of the sulfuric acid increases continuously from 0.1 mol / L to 2.0 mol / L at a rate of 0.05 mol / L per minute. The pulse frequency of the periodic variable-frequency pulse pump increases periodically from 0.5 Hz to 50 Hz, and the volumetric flow rate of the stripping solution ejected from the nozzle of the water distributor at the lower end of the water distributor increases periodically from 0.5 mL / min to 5.0 mL / min, with a period value of one cycle every 10 minutes and a rate of increase of 0.5 mL per minute within each cycle. The stripping solution droplets ejected from the nozzle of the water distributor at the lower end of the water distributor are in a discrete dispersed phase state, and the number of droplets varies with the pulse frequency of the periodic variable-frequency pulse pump. The concentration of sulfuric acid in the droplets varies with the concentration of sulfuric acid in the second intermediate liquid storage device. Stripping liquid droplets moving in a discrete flow come into countercurrent contact with the alkali metal ion-laden organic phase contained in the device from top to bottom, eventually coalescing in the aqueous phase chamber at the bottom of the non-steady flow discrete stripping device before flowing out of the bottom aqueous phase outlet. An automatic stepping collector is used to collect the stripping raffinate flowing out of the aqueous phase outlet at the bottom of the non-steady flow discrete stripping device. The automatic stepping collector rotates at a constant speed for 5 minutes, i.e., once every 5 minutes. The stripping raffinate is collected and the alkali metal ion concentration therein is determined. A graph is plotted with the cumulative volume of stripping liquid collected by the automatic stepping collector as the horizontal axis and the concentration of various alkali metal ions in the stripping liquid collected each time as the vertical axis.The results showed that the stripping solution collected by the automatic collector within the first 5 minutes was primarily lithium ions, with a separation coefficient of 38,000 for lithium ions and sodium ions, and a separation coefficient greater than 102,500 for other coexisting alkali metal ions. The stripping solution collected within the first 6 to 10 minutes was primarily sodium ions, with a separation coefficient of 11,320 for sodium ions and potassium ions, and a separation coefficient greater than 27,000 for other coexisting alkali metal ions. The stripping solution collected within the first 11 to 15 minutes was primarily potassium ions, with a separation coefficient of 580 for potassium ions and 9600 for other coexisting alkali metal ions. The stripping solution collected within the first 16 to 20 minutes was primarily rubidium ions, with a separation coefficient of 120 for rubidium ions and cesium ions. The stripping solution collected after the 21st minute was primarily cesium ions. Excellent separation of the five ions, cesium, rubidium, potassium, sodium, and lithium, was achieved.

[0164] Example 7

[0165] A 10% by volume t-BAMBP kerosene solution was mixed with a mixed aqueous solution containing lithium, sodium, potassium, rubidium, and cesium ions in a 1:1 volume ratio for 0.1 hour. After oil-water separation, the upper organic phase was collected to obtain an alkali metal ion-loaded organic phase. The total alkali metal ion concentration in the loaded organic phase was 0.1 g / L. This loaded organic phase, containing lithium, sodium, potassium, rubidium, and cesium ions, was pumped from the lower oil phase inlet of the unsteady-flow discrete stripping unit in a system for separating alkali metal ions by unsteady-flow discrete stripping into a hollow straight tubular column with a length of 200.0 cm and an inner diameter of 10.0 cm. The pumping rate of the alkali metal ion-loaded organic phase was 20.0 mL / min. Pure water was pumped from the third liquid replenishing unit into the stirred second intermediate liquid storage unit. The outlet valve of the third liquid replenishing unit was then closed, and commercial hydrochloric acid was continuously pumped from the fourth liquid replenishing unit into the stirred second intermediate liquid storage unit. At the same time, the periodic variable frequency pulse pump is turned on, the periodic increase range and period value of the pulse frequency are set, and the hydrochloric acid aqueous solution obtained by mixing in the second intermediate liquid storage device is pumped from the water inlet of the upper water distributor of the non-steady flow discrete stripping device; wherein the molar concentration of hydrochloric acid increases continuously from 0.1 mol / L to 2.0 mol / L, and the increase rate is 0.20 mol / L per minute. The pulse frequency of the periodic variable frequency pulse pump increases continuously and periodically from 0.5 Hz to 50 Hz, and the volume flow rate of the stripping liquid sprayed from the nozzle of the water spray pipe at the lower end of the water distributor increases continuously and periodically from 0.5 mL / min to 5.0 mL / min, with a period value of one cycle per 1 minute, and the flow rate increase rate in each cycle is 5.0 mL per minute. The inner diameter of the water spray pipe is 5.0 mm and the length is 40.0 mm. Two layers of sieve plates are fixed at the lower end of the spring shaft of the water spray pipe, and their diameters are both 4.95 mm. Stripping solution droplets ejected from the nozzles of the spray pipe at the lower end of the water distributor are in a discrete, dispersed phase. The number of droplets varies with the pulse frequency of the periodically variable frequency pulse pump, and the concentration of hydrochloric acid in the droplets varies with the concentration of hydrochloric acid in the second intermediate liquid storage device. The stripping solution droplets, moving in a discrete flow, come into countercurrent contact with the alkali metal ion-laden organic phase contained within the device from top to bottom. They ultimately coalesce within the aqueous phase chamber at the bottom of the non-steady flow discrete stripping device before flowing out of the bottom aqueous phase outlet. The stripping solution exiting the aqueous phase outlet at the bottom of the non-steady flow discrete stripping device is collected by an automatic stepping collector. The automatic stepping collector rotates at a constant speed every 40 minutes, i.e., once every 40 minutes. The stripping solution collected is then tested for alkali metal ion concentration. A graph is plotted with the cumulative volume of stripping solution collected by the automatic stepping collector as the horizontal axis and the concentration of various alkali metal ions in the stripping solution collected at each time as the vertical axis.The results showed that the stripping solution collected by the automatic collector from 0 to 40 minutes was primarily composed of lithium ions, with a separation coefficient of 54,310 for lithium ions and sodium ions, and a separation coefficient greater than 112,200 for other coexisting alkali metal ions. The stripping solution from 41 to 80 minutes was primarily composed of sodium ions, with a separation coefficient of 11,620 for sodium ions and potassium ions, and a separation coefficient greater than 25,000 for other coexisting alkali metal ions. The stripping solution from 81 to 120 minutes was primarily composed of potassium ions, with a separation coefficient of 420 for potassium ions and 9,500 for other coexisting alkali metal ions. The stripping solution from 121 to 160 minutes was primarily composed of rubidium ions, with a separation coefficient of 136 for rubidium ions and cesium ions. The stripping solution collected after 161 minutes was primarily composed of cesium ions. Excellent separation of the five ions, cesium, rubidium, potassium, sodium, and lithium, was achieved.

[0166] Example 8

[0167] The loaded organic phases collected at different time periods in Example 2 were mixed uniformly and pumped from the lower oil phase inlet of the non-steady-flow discrete stripping unit in a system for separating alkali metal ions by non-steady-flow discrete stripping into a hollow straight tubular column with a length of 60.0 cm and an inner diameter of 4.5 cm. The pumping rate of the alkali metal ion-loaded organic phase was 5.0 mL / min. The total concentration of alkali metal ions in the loaded organic phase was 1 g / L. Pure water was pumped from the third rehydration unit into the stirred second intermediate liquid storage unit. The outlet valve of the third rehydration unit was then closed, and commercially available sulfuric acid was continuously pumped from the fourth rehydration unit into the stirred second intermediate liquid storage unit. Simultaneously, a periodic variable-frequency pulse pump was activated, with a set pulse frequency increase range and period value. The mixed sulfuric acid aqueous solution in the second intermediate liquid storage unit was pumped from the water inlet of the upper water distributor of the non-steady-flow discrete stripping unit into the water distribution unit. The molar concentration of the sulfuric acid was continuously increased from 0.1 mol / L to 2.0 mol / L at a rate of 0.10 mol / L per minute. The pulse frequency of the periodic variable frequency pulse pump increases continuously and periodically from 0.5 Hz to 30 Hz, and the volume flow rate of the stripping liquid ejected from the nozzle of the spray pipe at the lower end of the water distributor increases continuously and periodically from 0.5 mL / min to 3.0 mL / min, with a cycle value of one cycle every 6 minutes, and the rate of increase of the flow rate within each cycle is 0.50 mL per minute. The inner diameter of the spray pipe is 3.0 mm and the length is 18.0 mm. A sieve plate with a diameter of 2.95 mm is fixed to the lower end of the spring shaft of the spray pipe. The stripping liquid droplets ejected from the nozzle of the spray pipe at the lower end of the water distributor are in a discrete dispersed phase state, and the number of droplets varies with the pulse frequency of the periodic variable frequency pulse pump. The concentration of sulfuric acid in the droplets varies with the concentration of sulfuric acid in the second intermediate liquid storage device. Stripping liquid droplets moving in a discrete flow come into countercurrent contact with the alkali metal ion-laden organic phase contained in the device from top to bottom, and ultimately coalesce in the aqueous phase chamber at the bottom end of the non-steady flow discrete stripping device before flowing out of the bottom aqueous phase outlet. An automatic stepping collector is used to collect the stripping raffinate flowing out of the aqueous phase outlet at the bottom end of the non-steady flow discrete stripping device. The automatic stepping collector rotates at a constant speed every 10 minutes, i.e., it rotates once every 10 minutes. The stripping raffinate is collected and the alkali metal ion concentration therein is determined. A graph is plotted with the cumulative volume of stripping liquid collected by the automatic stepping collector as the horizontal axis and the concentration of various alkali metal ions in the stripping liquid collected each time as the vertical axis.The results showed that the stripping solution collected by the automatic collector within the first 0-10 minutes was primarily composed of lithium ions, with a separation coefficient of 42,330 for lithium ions and sodium ions, and a separation coefficient greater than 98,000 for other coexisting alkali metal ions. The stripping solution collected within the first 11-20 minutes was primarily composed of sodium ions, with a separation coefficient of 15,180 for sodium ions and potassium ions, and a separation coefficient greater than 30,000 for other coexisting alkali metal ions. The stripping solution collected within the first 21-30 minutes was primarily composed of potassium ions, with a separation coefficient of 850 for potassium ions and 9300 for other coexisting alkali metal ions. The stripping solution collected within the first 31-40 minutes was primarily composed of rubidium ions, with a separation coefficient of 220 for rubidium ions and cesium ions. The stripping solution collected after the 41st minute was primarily composed of cesium ions. Excellent separation of the five ions, cesium, rubidium, potassium, sodium, and lithium, was achieved.

[0168] Example 9

[0169] A system for separating alkali metal ions by non-steady flow discrete stripping, such as Figure 18 As shown, it includes five sets of non-steady flow discrete stripping systems for separating alkali metal ions connected in series. The hollow straight tube column of each system's non-steady flow discrete stripping device has a size of 100.0 cm × 6.5 cm (length × inner diameter). The inner diameter of the water spray pipe is 4.0 mm and the length is 26.0 mm. A three-layer sieve plate with a diameter of 3.95 mm is fixed to the lower end of the spring shaft of the water spray pipe. The upper oil phase overflow outlet of the hollow straight tube column of the upstream system's non-steady flow discrete stripping device is connected to the lower oil phase inlet of the hollow straight tube column of the downstream system's non-steady flow discrete stripping device. The stripped organic phase overflowing from the top oil phase chamber outlet of the upstream system's non-steady flow discrete stripping device is continuously pumped into the lower oil phase inlet of the downstream system's non-steady flow discrete stripping device. The water distributor of each system's non-steady flow discrete stripping device separately pumps an aqueous solution of hydrochloric acid or sulfuric acid as the stripping liquid. The stripping raffinate flowing out of the aqueous phase outlet of the aqueous phase chamber at the bottom of the hollow straight tube column of the non-steady flow discrete stripping device of each system is collected by an automatic stepping collector.

[0170] A method for stripping and separating an organic phase loaded with five alkali metal ions, namely lithium, sodium, potassium, rubidium and cesium, by using the above system, such as Figure 18 As shown, the steps are as follows:

[0171] A 30% by volume t-BAMBP kerosene solution was mixed with a mixed aqueous solution containing lithium, sodium, potassium, rubidium, and cesium ions at a volume ratio of 1:10 for 0.1 hour. After oil-water separation, the upper organic phase was collected to obtain an alkali metal ion-loaded organic phase. The total alkali metal ion concentration in the loaded organic phase was 3 g / L. This loaded organic phase, containing lithium, sodium, potassium, rubidium, and cesium ions, was pumped from the lower oil phase inlet of the unsteady-flow discrete stripping unit in the first-stage unsteady-flow discrete stripping system into a hollow straight tubular column. The pumping rate of the alkali metal ion-loaded organic phase was 30.0 mL / min. Pure water was pumped from the third rehydration unit into the stirred second intermediate liquid storage unit. The outlet valve of the third rehydration unit was then closed, and commercial sulfuric acid was continuously pumped from the fourth rehydration unit into the stirred second intermediate liquid storage unit. At the same time, a periodic variable-frequency pulse pump is turned on, and the pulse frequency is set to a periodic increase range and a period value. The mixed sulfuric acid aqueous solution in the second intermediate liquid storage device is pumped from the water inlet of the upper water distributor of the non-steady-flow discrete stripping device into the second intermediate liquid storage device. The molar concentration of the sulfuric acid increases continuously from 0.1 mol / L to 2.0 mol / L at a rate of 0.20 mol / L per minute. The pulse frequency of the periodic variable-frequency pulse pump increases periodically from 0.5 Hz to 50 Hz, and the volumetric flow rate of the stripping solution ejected from the nozzle of the water distributor at the lower end of the water distributor increases periodically from 0.5 mL / min to 5.0 mL / min, with a period value of one cycle every 10 minutes and a rate of increase of 0.5 mL per minute within each cycle. The stripping solution droplets ejected from the nozzle of the water distributor at the lower end of the water distributor are in a discrete dispersed phase state, and the number of droplets varies with the pulse frequency of the periodic variable-frequency pulse pump. The concentration of sulfuric acid in the droplets varies with the concentration of sulfuric acid in the second intermediate liquid storage device. Stripping liquid droplets, moving in a discrete flow, countercurrently contact the alkali metal ion-laden organic phase contained within the apparatus from top to bottom, ultimately coalescing within the bottom aqueous phase chamber of the non-steady flow discrete stripping apparatus before flowing out of the bottom aqueous phase outlet. The stripped organic phase, overflowing from the top oil phase chamber outlet of the first-stage non-steady flow discrete stripping apparatus, was continuously pumped into the lower oil phase inlet of the second-stage non-steady flow discrete stripping apparatus at a volumetric flow rate of 30.0 mL / min. The second-stage non-steady flow discrete stripping apparatus operated identically to the first-stage non-steady flow discrete stripping apparatus. The sulfuric acid concentration in the stripping liquid pumped into the water inlet of the upper water distributor of the second-stage non-steady flow discrete stripping apparatus increased continuously from 0.1 mol / L to 2.0 mol / L at a rate of 0.2 mol / L per minute. The third-, fourth-, and fifth-stage non-steady flow discrete stripping apparatuses performed the same operations as described above. The volume flow rate of the alkali metal ion-loaded organic phase pumped into the lower oil phase inlet of each stage of the non-steady flow discrete stripping device was controlled to be 30.0 mL / min.The concentration of hydrochloric acid or sulfuric acid in the stripping solution pumped into the water distributor inlet of the upper water distributor of each stage of the non-steady-flow discrete stripping unit was increased continuously from 0.1 mol / L to 2.0 mol / L at a rate of 0.2 mol / L / minute (third stage), 0.4 mol / L / minute (fourth stage), and 0.6 mol / L / minute (fifth stage), respectively. The stripping solution flowing out of the aqueous phase outlet at the bottom of each stage of the non-steady-flow discrete stripping unit was collected by an automatic stepping collector. The automatic stepping collector rotated at a constant speed every 5 minutes, i.e., once every 5 minutes. The stripping solution was collected and the alkali metal ion concentration was determined. A graph was plotted with the cumulative volume of the stripping solution collected by the automatic stepping collector as the horizontal axis and the concentration of various alkali metal ions in the stripping solution collected at each time as the vertical axis. The results showed that the stripping solution flowing out of the bottom aqueous phase outlet of the first-stage unsteady-flow discrete stripping unit was primarily composed of lithium ions, with a separation coefficient greater than 112,000 for lithium ions and other coexisting alkali metal ions. The stripping solution flowing out of the second-stage unsteady-flow discrete stripping unit was primarily composed of sodium ions, with a separation coefficient greater than 9,200 for sodium ions and other coexisting alkali metal ions. The stripping solution flowing out of the third-stage unsteady-flow discrete stripping unit was primarily composed of potassium ions, with a separation coefficient greater than 1,300 for potassium ions and other coexisting alkali metal ions. The stripping solution flowing out of the fourth-stage unsteady-flow discrete stripping unit was primarily composed of rubidium ions, with a separation coefficient of 320 for rubidium ions and other coexisting alkali metal ions. The stripping solution flowing out of the fifth-stage unsteady-flow discrete stripping unit was primarily composed of cesium ions. Excellent separation of the five ions, cesium, rubidium, potassium, sodium, and lithium, was achieved.

[0172] Example 10

[0173] Three sets of non-steady flow discrete stripping systems for separating alkali metal ions are connected in series. The dimensions of the hollow straight tube column of each system's non-steady flow discrete stripping device are 120.0 cm × 7.5 cm (length × inner diameter). The inner diameter of the water spray pipe is 4.5 mm and the length is 34.0 mm. Two layers of sieve plates, both with a diameter of 4.45 mm, are fixed to the lower end of the spring shaft of the water spray pipe. The upper oil phase overflow outlet of the hollow straight tube column of the non-steady flow discrete stripping device of the upstream system is connected to the lower oil phase inlet of the hollow straight tube column of the non-steady flow discrete stripping device of the downstream system. The stripped organic phase overflowing from the top oil phase chamber outlet of the non-steady flow discrete stripping device of the upstream system is continuously pumped into the lower oil phase inlet of the non-steady flow discrete stripping device of the downstream system. An aqueous solution of hydrochloric acid or sulfuric acid is separately pumped into the water distributor of each system's non-steady flow discrete stripping device as the stripping liquid. The stripping raffinate flowing out of the aqueous phase outlet of the aqueous phase chamber at the bottom of the hollow straight tube column of the non-steady flow discrete stripping device of each system is collected by an automatic stepping collector.

[0174] The above system is used to strip and separate the loaded organic phase containing three alkali metal ions of rubidium, cesium and potassium. The steps are as follows:

[0175] A 30% by volume t-BAMBP kerosene solution was mixed with a mixed aqueous solution containing rubidium, cesium, and potassium ions in a 1:5 volume ratio for 0.5 hours. After oil-water separation, the upper organic phase was collected to obtain an alkali metal ion-loaded organic phase. The total concentration of alkali metal ions in the loaded organic phase was 1 g / L. This loaded organic phase, containing rubidium, cesium, and potassium ions, was pumped from the lower oil phase inlet of the unsteady-flow discrete stripping unit in the first-stage unsteady-flow discrete stripping system into a hollow straight tubular column. The pumping rate of the alkali metal ion-loaded organic phase was 0.1 mL / min. Pure water was pumped from the third rehydration unit into the stirred second intermediate liquid storage unit. The outlet valve of the third rehydration unit was then closed, and commercial hydrochloric acid was continuously pumped from the fourth rehydration unit into the stirred second intermediate liquid storage unit. At the same time, a periodic variable-frequency pulse pump is turned on, and the periodic increase range and cycle value of the pulse frequency are set. The hydrochloric acid aqueous solution mixed in the second intermediate liquid storage device is pumped from the water inlet of the upper water distributor of the non-steady-flow discrete stripping device. The molar concentration of the hydrochloric acid continuously increases from 0.1 mol / L to 2.0 mol / L, with an increase rate of 0.20 mol / L per minute. The pulse frequency of the periodic variable-frequency pulse pump is periodically increased from 0.5 Hz to 50 Hz, and the volume flow rate of the stripping solution ejected from the nozzle of the water spray pipe at the lower end of the water distributor is periodically increased from 0.5 mL / min to 5.0 mL / min, with a cycle value of one cycle every 5 minutes and an increase rate of 1.0 mL per minute within each cycle. The stripping solution droplets ejected from the nozzle of the water spray pipe at the lower end of the water distributor are in a discrete dispersed phase state, and the number of droplets varies with the pulse frequency of the periodic variable-frequency pulse pump. The concentration of hydrochloric acid in the droplets varies with the concentration of hydrochloric acid in the second intermediate liquid storage device. Stripping liquid droplets, moving in a discrete flow, countercurrently contact the alkali metal ion-laden organic phase contained within the apparatus from top to bottom, ultimately coalescing within the bottom aqueous phase chamber of the non-steady flow discrete stripping apparatus before flowing out of the bottom aqueous phase outlet. The stripped organic phase, overflowing from the top oil phase chamber outlet of the first-stage non-steady flow discrete stripping apparatus, was continuously pumped into the lower oil phase inlet of the second-stage non-steady flow discrete stripping apparatus at a volumetric flow rate of 0.1 mL / min. The hydrochloric acid concentration in the stripping liquid pumped into the water inlet of the upper water distributor of the second-stage non-steady flow discrete stripping apparatus increased continuously from 0.1 mol / L to 2.0 mol / L at a rate of 0.4 mol / L per minute. The volumetric flow rate of the hydrochloric acid aqueous solution ejected from the spray nozzle at the lower end of the water distributor was periodically increased from 0.5 mL / min to 5.0 mL / min, with a cycle of 2 minutes and a rate of 2.5 mL / min per cycle.The stripped organic phase overflowing from the top oil phase chamber outlet of the second-stage non-steady-flow discrete stripping unit was continuously pumped into the lower oil phase inlet of the third-stage non-steady-flow discrete stripping unit. The volumetric flow rate of the alkali metal ion-laden organic phase was 0.1 mL / min. The hydrochloric acid concentration in the stripping solution pumped into the water inlet of the upper water distributor of the third-stage non-steady-flow discrete stripping unit was continuously increased from 0.1 mol / L to 2.0 mol / L at a rate of 0.6 mol / L per minute. The volumetric flow rate of the hydrochloric acid aqueous solution discharged from the spray nozzle at the lower end of the water distributor was periodically increased from 0.5 mL / min to 5.0 mL / min, with a cycle of 1 minute and a rate of 5.0 mL / min per cycle. The stripping raffinate flowing from the bottom aqueous phase outlet of each non-steady-flow discrete stripping unit was collected using an automatic stepping collector. The automatic stepping collector rotated at a constant speed every 10 minutes, collecting the stripping raffinate and measuring its alkali metal ion concentration. A graph was plotted with the cumulative volume of stripping solution collected by the automatic stepping collector as the horizontal axis and the concentration of various alkali metal ions in the stripping solution collected at each time as the vertical axis. The results showed that the stripping solution exiting the aqueous phase outlet of the bottom aqueous phase chamber of the first-stage unsteady flow discrete stripping device was primarily composed of potassium ions, with a separation coefficient greater than 1300 between potassium ions and other coexisting alkali metal ions. The stripping solution exiting the aqueous phase outlet of the bottom aqueous phase chamber of the second-stage unsteady flow discrete stripping device was primarily composed of rubidium ions, with a separation coefficient of 660 between rubidium ions and cesium ions. The stripping solution exiting the aqueous phase outlet of the bottom aqueous phase chamber of the third-stage unsteady flow discrete stripping device was primarily composed of cesium ions. Excellent separation of cesium, rubidium, and potassium ions was achieved.

[0176] Example 11

[0177] A system for separating alkali metal ions by non-steady flow discrete extraction and stripping, such as Figure 19 As shown, it includes a non-steady flow discrete extraction system and a non-steady flow discrete stripping system, which are connected in series. Among them, the hollow straight tube column 2 of the non-steady flow discrete extraction device has a size of 70.0cm×6.0cm (length×inner diameter), the inner tube inner diameter of the oil distributor spray head is 0.3mm, and the inner diameter of the outer tube is 0.6mm. The hollow straight tube column 19 of the non-steady flow discrete stripping device has a size of 140.0cm×8.0cm (length×inner diameter). The inner diameter of the water spray pipe is 3.5mm and the length is 22.0mm. Three layers of sieve plates are fixed at the lower end of the spring shaft of the water spray pipe, and their diameters are all 3.45mm.

[0178] A method for extracting and separating a mixed aqueous solution containing five ions of lithium, sodium, potassium, rubidium and cesium using the above device, such as Figure 19 As shown, the steps are as follows:

[0179] A mixed aqueous solution containing lithium, sodium, potassium, rubidium, and cesium ions with a 0.5 mol / L alkali concentration was pumped from the upper aqueous phase inlet of a non-steady flow discrete extraction device in a system for separating alkali metal ions by non-steady flow discrete extraction into a hollow straight tubular column. The pumping rate of the mixed aqueous solution containing alkali metal ions was 3.0 mL / min. The total concentration of alkali metal ions was 2 g / L. Kerosene was then pumped from the first rehydration device into a first intermediate liquid storage device with stirring. The outlet valve of the first rehydration device was closed, and t-BAMBP was continuously pumped from the second rehydration device into the first intermediate liquid storage device with stirring. At the same time, a periodic flow pump was turned on, and the periodic increase range and cycle value of the pump flow rate were set. The organic solution containing the extractant, obtained after mixing in the first intermediate liquid storage device, was pumped into the oil chamber of the oil distributor through the oil phase inlet at the bottom of the unsteady flow discrete extraction device. The volume percentage of t-BAMBP in the organic solution containing the extractant was continuously increased from 1% to 30% at a rate of 3% per minute. The volume flow rate of the organic solution containing the extractant ejected from the nozzle of the oil distributor nozzle was continuously increased from 0.5 mL / min to 5.0 mL / min, with a cycle value of one cycle every 10 minutes and a flow rate increase rate of 0.5 mL per minute within each cycle. Then, air was pumped into the air inlet at the bottom end of the unsteady flow discrete extraction device at a volume flow rate of 0.5 mL / min. The hollow oil droplets encapsulating the bubbles ejected from the nozzle of the oil distributor nozzle are in a discrete dispersed phase state, and the number of oil droplets varies with the periodic flow rate of the periodic flow pump. The concentration of the organic extractant in the oil droplets varies with the concentration of the extractant in the first intermediate liquid storage device. The hollow oil droplets encapsulating the bubbles, moving in a discrete flow, come into countercurrent contact with the mixed aqueous solution containing alkali metal ions contained in the device from bottom to top, ultimately breaking and coalescing at the top porous bubble-breaking baffle of the non-steady flow discrete extraction device before flowing out of the top oil phase overflow outlet. The loaded organic phase flowing out of the top oil phase overflow outlet of the non-steady flow discrete extraction device is continuously pumped into the lower oil phase inlet of the non-steady flow discrete stripping device using another periodic flow pump. The volumetric flow rate of the loaded organic phase flowing out of the top oil phase overflow outlet of the upstream non-steady flow discrete extraction device is controlled to be equal to the volumetric flow rate of the loaded organic phase pumped into the lower oil phase inlet of the downstream non-steady flow discrete stripping device. Pure water is pumped from the third liquid replenishing device into the second intermediate liquid storage device with stirring. The outlet valve of the third liquid replenishing device is then closed, and commercially available sulfuric acid is continuously pumped from the fourth liquid replenishing device into the second intermediate liquid storage device with stirring. Simultaneously, a periodic variable frequency pulse pump is turned on, and the periodic increase range and period value of the pulse frequency are set. The mixed sulfuric acid aqueous solution in the second intermediate liquid storage device is pumped from the water inlet of the upper water distributor of the non-steady flow discrete stripping device into the water inlet; wherein the molar concentration of the sulfuric acid is continuously increased from 0.1 mol / L to 2.0 mol / L, at a rate of 0.20 mol / L per minute.The pulse frequency of the periodic variable frequency pulse pump increases continuously from 0.5 Hz to 50 Hz, and the volumetric flow rate of the stripping solution ejected from the nozzle of the spray pipe at the lower end of the water distributor increases continuously from 0.5 mL / min to 5.0 mL / min, with a cycle of 5 minutes and a rate of increase of 1.0 mL per minute within each cycle. The stripping solution droplets ejected from the nozzle of the spray pipe at the lower end of the water distributor are in a discrete dispersed phase state, and the number of droplets varies with the pulse frequency of the periodic variable frequency pulse pump. The concentration of sulfuric acid in the droplets varies with the concentration of sulfuric acid in the second intermediate liquid storage device. The stripping solution droplets, moving in a discrete flow, come into countercurrent contact with the alkali metal ion-laden organic phase contained in the device from top to bottom, ultimately coalescing in the aqueous phase chamber at the bottom end of the non-steady flow discrete stripping device before flowing out of the bottom aqueous phase outlet. The stripping solution raffinate flowing from the aqueous phase outlet at the bottom end of the non-steady flow discrete stripping device is collected by an automatic stepping collector. The automatic stepping collector rotates at a constant speed every 40 minutes, collecting the stripping raffinate and measuring its alkali metal ion concentration. A graph is plotted with the cumulative volume of stripping raffinate collected by the automatic stepping collector as the abscissa and the concentration of various alkali metal ions in the stripping raffinate collected at each time as the ordinate. The results showed that the stripping solution collected by the automatic collector from 0 to 40 minutes was primarily composed of lithium ions, with a separation coefficient of 45,100 for lithium ions and sodium ions, and a separation coefficient greater than 92,000 for other coexisting alkali metal ions. The stripping solution from 41 to 80 minutes was primarily composed of sodium ions, with a separation coefficient of 7,300 for sodium ions and potassium ions, and a separation coefficient greater than 20,000 for other coexisting alkali metal ions. The stripping solution from 81 to 120 minutes was primarily composed of potassium ions, with a separation coefficient of 820 for potassium ions and 4,500 for other coexisting alkali metal ions. The stripping solution from 121 to 160 minutes was primarily composed of rubidium ions, with a separation coefficient of 385 for rubidium ions and cesium ions. The stripping solution collected after 161 minutes was primarily composed of cesium ions. Excellent separation of the five ions, cesium, rubidium, potassium, sodium, and lithium, was achieved.

[0180] Example 12

[0181] The system described in Example 11 is used to extract and separate a mixed aqueous solution containing four ions of sodium, potassium, rubidium, and cesium. The steps are as follows:

[0182] A mixed aqueous solution with an alkali concentration of 1.0 mol / L and containing four ions (sodium, potassium, rubidium, and cesium) was pumped into a hollow straight tubular column from the upper aqueous phase inlet of a non-steady flow discrete extraction device in a system for separating alkali metal ions by non-steady flow discrete extraction. The pumping rate of the mixed aqueous solution containing alkali metal ions was 50.0 mL / min. The total concentration of alkali metal ions was 3 g / L. Kerosene was then pumped from the first rehydration device into a first intermediate liquid storage device with stirring. The outlet valve of the first rehydration device was closed, and t-BAMBP was continuously pumped from the second rehydration device into the first intermediate liquid storage device with stirring. At the same time, a periodic flow pump was activated, and the periodic increase range and cycle value of the pumped flow rate were set. The organic solution containing the extractant, obtained after mixing in the first intermediate liquid storage device, was pumped into the oil chamber of the oil distributor through the oil phase inlet at the bottom of the unsteady flow discrete extraction device. The volume percentage of t-BAMBP in the organic solution containing the extractant was continuously increased from 1% to 30% at a rate of 3% per minute. The volume flow rate of the organic solution containing the extractant ejected from the nozzle of the oil distributor nozzle was continuously increased from 0.5 mL / min to 4.0 mL / min, with a cycle value of one cycle every 10 minutes and a flow rate increase rate of 0.4 mL per minute within each cycle. Then, air was pumped into the air inlet at the bottom end of the unsteady flow discrete extraction device at a volume flow rate of 4.0 mL / min. The hollow oil droplets encapsulating the bubbles ejected from the nozzle of the oil distributor nozzle are in a discrete dispersed phase state, and the number of oil droplets varies with the periodic changes of the periodic flow pump. The concentration of the organic extractant in the oil droplets varies with the concentration of the extractant in the first intermediate liquid storage device. The hollow oil droplets encapsulating the bubbles, moving in a discrete flow, come into countercurrent contact with the mixed aqueous solution containing alkali metal ions contained in the device from bottom to top, and ultimately break and coalesce at the top porous bubble breaking baffle of the non-steady flow discrete extraction device before flowing out of the top oil phase overflow outlet. The loaded organic phase flowing out of the top oil phase overflow outlet of the non-steady flow discrete extraction device is continuously pumped into the lower oil phase inlet of the non-steady flow discrete stripping device using another periodic flow pump. The volume flow rate of the loaded organic phase flowing out of the top oil phase overflow outlet of the upstream non-steady flow discrete extraction device is controlled to be equal to the volume flow rate of the loaded organic phase pumped into the lower oil phase inlet of the downstream non-steady flow discrete stripping device. Pure water is pumped from the third liquid replenishing device into the second intermediate liquid storage device with stirring. The outlet valve of the third liquid replenishing device is then closed, and commercially available sulfuric acid is continuously pumped from the fourth liquid replenishing device into the second intermediate liquid storage device with stirring. Simultaneously, a periodic variable frequency pulse pump is turned on, and the periodic increase range and period value of the pulse frequency are set. The mixed sulfuric acid aqueous solution in the second intermediate liquid storage device is pumped from the water inlet of the upper water distributor of the non-steady flow discrete stripping device into the water inlet; wherein the molar concentration of the sulfuric acid is continuously increased from 0.1 mol / L to 2.0 mol / L, at a rate of 0.20 mol / L per minute.The pulse frequency of the periodic variable frequency pulse pump increases continuously from 0.5 Hz to 50 Hz, and the volumetric flow rate of the stripping solution ejected from the nozzle of the spray pipe at the lower end of the water distributor increases continuously from 0.5 mL / min to 5.0 mL / min, with a cycle of 5 minutes and a rate of increase of 1.0 mL per minute within each cycle. The stripping solution droplets ejected from the nozzle of the spray pipe at the lower end of the water distributor are in a discrete dispersed phase state, and the number of droplets varies with the pulse frequency of the periodic variable frequency pulse pump. The concentration of sulfuric acid in the droplets varies with the concentration of sulfuric acid in the second intermediate liquid storage device. The stripping solution droplets, moving in a discrete flow, come into countercurrent contact with the alkali metal ion-laden organic phase contained in the device from top to bottom, ultimately coalescing in the aqueous phase chamber at the bottom end of the non-steady flow discrete stripping device before flowing out of the bottom aqueous phase outlet. The stripping solution raffinate flowing from the aqueous phase outlet at the bottom end of the non-steady flow discrete stripping device is collected by an automatic stepping collector. The automatic stepping collector rotated at a constant speed every 10 minutes, collecting the stripping raffinate and measuring its alkali metal ion concentration. A graph was plotted with the cumulative volume of stripping solution collected by the automatic stepping collector as the abscissa and the concentration of various alkali metal ions in the stripping solution collected at each time as the ordinate. The results showed that the stripping solution collected by the automatic collector from the 0th to the 10th minute was primarily composed of sodium ions, with a separation coefficient of 9120 for sodium ions and greater than 30,000 for other coexisting alkali metal ions. The stripping solution collected from the 11th to the 20th minute was primarily composed of potassium ions, with a separation coefficient of 910 for potassium ions and greater than 6100 for other coexisting alkali metal ions. The stripping solution collected from the 21st to the 30th minute was primarily composed of rubidium ions, with a separation coefficient of 216 for rubidium ions and cesium ions. The stripping solution collected from the 31st minute onwards was primarily composed of cesium ions. The four ions of cesium, rubidium, potassium and sodium were well separated.

[0183] The applicant declares that the present invention uses the above-described embodiments to illustrate the detailed process equipment and process flow of the present invention. However, the present invention is not limited to the above-described detailed process equipment and process flow, and does not mean that the present invention must rely on the above-described detailed process equipment and process flow in order to be implemented. Those skilled in the art should understand that any improvements to the present invention, including equivalent replacement of the raw materials used in the present invention, addition of auxiliary components, and selection of specific methods, fall within the scope of protection and disclosure of the present invention.

Claims

1. A system for the separation of alkali metal ions by non-steady flow discrete extraction, characterized in that: The system includes a non-steady flow discrete extraction device, a periodic flow pump, a first intermediate liquid storage device, a first liquid replenishing device, a second liquid replenishing device and a first collection device; The non-steady flow discrete extraction device is composed of a hollow straight tube column and an oil distributor; The ratio of the length of the hollow straight tube column to its inner diameter is 10:1 to 20:1; The hollow straight tube column is provided with an oil phase overflow outlet located on one side of the top tube wall, a water phase inlet located on the other side of the upper tube wall and lower than the oil phase overflow outlet, and a water phase outlet located on one side of the lower tube wall; The oil distributor is located at the bottom end of the hollow straight pipe column and is connected to the hollow straight pipe column by a flange; The oil distributor is composed of an injection head, an oil distributor oil chamber and an oil distributor air chamber; The oil distributor's spray head is composed of a set of hollow straight tubes nested inside and outside. The inner tube is the air inlet pipe, with an inner diameter of 0.05-0.5 mm, and is connected to the oil distributor's air chamber. The outer tube is the oil inlet pipe, with an inner diameter of 0.6-1.0 mm. A narrow gap between the inner and outer walls of the outer tube is connected to the oil chamber of the oil distributor. The nozzle of the oil distributor's spray head is oriented toward the top of the hollow straight tubes. An air inlet is provided at the lower end of the oil distributor air chamber, and the air inlet is communicated with the oil distributor air chamber; The side wall of the oil distributor oil chamber is provided with an oil inlet, which is communicated with the oil distributor oil chamber; A porous bubble-breaking baffle is provided at the upper end of the hollow straight tube column, and the porous bubble-breaking baffle is located below the oil phase overflow outlet at the top of the hollow straight tube column and above the water phase inlet on the upper tube wall; A contraction bell-shaped channel is provided inside the porous bubble breaking baffle; The periodic flow pump is a peristaltic pump whose pumping flow rate changes periodically; The first intermediate liquid storage device is a liquid storage tank with stirring, which is provided with a stirring device; The first and second fluid replenishing devices are fluid reservoirs; The outlet of the first intermediate liquid storage device is connected to the inlet of the periodic flow pump; The inlet of the first intermediate liquid storage device is connected to the outlets of the first liquid replenishing device and the second liquid replenishing device respectively; The outlet of the periodic flow pump is connected to the oil inlet on the side wall of the oil chamber of the oil distributor of the unsteady flow discrete extraction device; The first collecting device is an automatic stepping collector, and the inlet of the automatic stepping collector is connected to the oil phase overflow outlet at the top of the hollow straight tube column.

2. A system for separating alkali metal ions by non-steady flow discrete stripping, characterized in that: The system includes a non-steady flow discrete stripping device, a periodic variable frequency pulse pump, a second intermediate liquid storage device, a third liquid replenishing device, a fourth liquid replenishing device and a second collecting device; The non-steady flow discrete stripping device is composed of a hollow straight tube column, an oil phase chamber, a water phase chamber and a water distributor; The ratio of the length of the hollow straight tube column to its inner diameter is 10:1 to 20:1; An oil inlet is provided on one side of the lower wall of the hollow straight pipe column; The oil phase chamber is located at the top of the hollow straight tube column and is connected to the hollow straight tube column by a flange; The water phase chamber is located at the bottom end of the hollow straight tube column and is connected to the hollow straight tube column by a flange; The oil phase chamber is provided with an oil phase overflow outlet located on one side of the top tube wall; The water phase chamber is provided with a water phase outlet located on one side of the bottom tube wall; The water distributor is located on the upper part of the hollow straight pipe column and below the flange connecting the oil phase chamber and the hollow straight pipe column; The water distributor includes a water inlet, a diversion cavity, a water spraying orifice plate and a water spraying pipe; The upper end of the water spray pipe is connected to the diversion cavity of the water distributor and is welded and fixed to the orifice of the water spray orifice plate in a one-to-one correspondence; The inner diameter of the water spray pipe is 2.0-5.0 mm; the length-to-inner-diameter ratio of the water spray pipe is 5:1-8:1; A guide orifice is provided inside the upper end of the water spray pipe, and the guide orifice is welded and fixed to the inner wall of the upper end of the water spray pipe; A spring shaft is provided inside the water spray pipe, the upper end of the spring shaft is connected and fixed to the center hole of the guide orifice plate by a coupling, the lower end of the spring shaft is provided with one or more sieve plates arranged in upper and lower layers, the center hole of the sieve plate is connected and fixed to the lower end of the spring shaft by a coupling, and the diameter of the sieve plate is 1.95-4.95 mm; The spring shaft provided in the water spray pipe can freely move up and down relative to the inner wall of the water spray pipe and along the length direction of the water spray pipe; when the spring shaft freely moves up and down, it can drive one or more sieve plates fixed at the lower end of the spring shaft to move up and down relative to the inner wall of the water spray pipe; A sieve plate fixed at the lower end of the spring shaft is provided with a channel in the shape of a bell mouth that contracts upward and downward; The lower end nozzle of the water spray pipe faces the bottom end of the hollow straight pipe column; A first porous water retaining plate is provided at the upper end of the hollow straight pipe column, and the first porous water retaining plate is located below the upper flange and above the water distributor; A second porous water retaining plate is provided at the lower end of the hollow straight pipe column, and the second porous water retaining plate is located above the lower flange and below the oil inlet of the lower side wall of the hollow straight pipe column; The first porous water retaining plate and the second porous water retaining plate are both provided with contraction bell-shaped channels; The periodic variable frequency pulse pump is a plunger pump with a periodically changing pulse frequency; The second intermediate liquid storage device is a liquid storage tank with stirring, which is provided with a stirring device; The third and fourth fluid replenishing devices are fluid storage tanks; The outlet of the second intermediate liquid storage device is connected to the inlet of the periodic variable frequency pulse pump; The inlet of the second intermediate liquid storage device is connected to the outlet of the third liquid replenishing device and the fourth liquid replenishing device respectively; The outlet of the periodic variable frequency pulse pump is connected to the water inlet of the water distributor of the non-steady flow discrete stripping device; The second collecting device is an automatic stepping collector, and the inlet of the automatic stepping collector is connected to the water phase outlet of the water phase chamber at the lower end of the hollow straight tube column.

3. A method for separating alkali metal ions by non-steady flow discrete extraction, characterized in that: The system for separating alkali metal ions by non-steady flow discrete extraction according to claim 1 comprises the following steps: (1) Pumping a mixed aqueous solution containing alkali metal ions from the upper aqueous phase inlet of the non-steady flow discrete extraction device at a pumping volume flow rate of 0.0 to 20.0 mL / min; the mixed aqueous solution containing alkali metal ions moves from top to bottom in the device, and then flows out from the aqueous phase outlet at the lower part of the non-steady flow discrete extraction device to obtain a raffinate aqueous phase; pumping an organic solvent from a first liquid replenishing device into a first intermediate liquid storage device with stirring, then closing the outlet valve of the first liquid replenishing device, and continuously pumping an organic extractant from a second liquid replenishing device into the first intermediate liquid storage device with stirring; At the same time, the periodic flow pump is turned on, and the periodic increase range and periodic value of the pumping flow rate are set. The organic solution containing the extractant obtained after mixing in the first intermediate liquid storage device is pumped into the oil chamber of the oil distributor from the oil phase inlet at the lower part of the non-steady flow discrete extraction device; then, air is pumped into the oil chamber of the oil distributor from the air inlet at the bottom end of the non-steady flow discrete extraction device; the oil droplets containing the extractant or the hollow oil droplets encapsulating bubbles ejected from the nozzle of the oil distributor nozzle are in a discrete dispersed phase state, and the number of oil droplets varies with the periodic flow rate of the periodic flow pump, and the concentration of the organic extractant in the oil droplets varies with the concentration of the extractant in the first intermediate liquid storage device; the oil droplets containing the extractant or the hollow oil droplets encapsulating bubbles moving in a discrete flow come into countercurrent contact with the mixed aqueous solution containing alkali metal ions contained in the device from bottom to top, and finally, after breaking and coalescing at the top porous bubble breaking baffle of the non-steady flow discrete extraction device, they flow out from the top oil phase overflow outlet to obtain a loaded organic phase; (2) continuously collecting in batches the loaded organic phase flowing out of the oil phase overflow outlet at the top of the non-steady flow discrete extraction device in step (1); wherein the collection time of each batch is independently selected from 5 to 40 minutes, and respectively obtaining an enriched organic phase having a loading concentration of a certain alkali metal ion much higher than that of other coexisting alkali metal ions; (3) The loaded organic phases obtained in step (2) and extracted with different alkali metal ions in different time periods are mixed with a hydrochloric acid or sulfuric acid aqueous solution with a concentration of 0.1 to 2.0 mol / L at a volume ratio of 1:1 to 10:1 for 0.1 to 2 h for back extraction; after the oil and water phases are separated, the lower aqueous phases are collected to obtain enriched aqueous solutions containing a certain alkali metal ion concentration much higher than that of other coexisting alkali metal ions.

4. The method according to claim 3, wherein The mixed aqueous solution containing alkali metal ions in step (1) is an alkaline aqueous solution containing a combination of at least three or more of the five alkali metal cations of lithium, sodium, potassium, rubidium, and cesium, and the total concentration of alkali metal ions is 0.1~5g / L; the organic extractant is t-BAMBP; the organic solvent is commercially available kerosene or xylene; the organic solution containing the extractant is prepared by dissolving t-BAMBP in kerosene or xylene; in the organic solution containing the extractant, the volume percentage of t-BAMBP increases continuously from 1% to 30%, and the increase rate is 0.5%~3% per minute; the volume flow rate of the organic solution containing the extractant ejected from the nozzle of the oil distributor nozzle increases periodically and continuously from 0.5mL / min to 5.0mL / min, the cycle value is one cycle every 1~10 minutes, and the flow rate increase rate in each cycle is 0.5~5.0mL per minute; the volume flow rate of air pumped into the air inlet at the bottom end of the device is 0~5.0mL / min.

5. The method according to claim 3, wherein In step (2), the loaded organic phase flowing out of the oil phase overflow outlet at the top of the non-steady flow discrete extraction device of step (1) is continuously collected in batches by the automatic stepping collector of the first collecting device; the automatic stepping collector rotates at a constant speed to perform continuous batch collection; wherein the time interval of the constant speed rotation of the automatic stepping collector is 5 to 40 minutes.

6. A method for separating alkali metal ions by non-steady flow discrete stripping, characterized in that: The system for separating alkali metal ions by non-steady flow discrete stripping according to claim 2 comprises the following steps: (1) Pumping the loaded organic phase containing alkali metal ions after extraction from the oil phase inlet at the lower part of the non-steady flow discrete stripping device at a pumping volume flow rate of 0.0~20.0mL / min; the loaded organic phase containing alkali metal ions moves from bottom to top in the device, and then overflows from the oil phase overflow outlet at the top of the non-steady flow discrete stripping device to obtain the organic phase after stripping; pumping pure water from the third liquid replenishing device into the second intermediate liquid storage device with stirring, then closing the outlet valve of the third liquid replenishing device, and continuously pumping commercially available hydrochloric acid or sulfuric acid from the fourth liquid replenishing device into the second intermediate liquid storage device with stirring; At the same time, a periodic variable frequency pulse pump is turned on, and a periodic increase range and a periodic value of the pulse frequency are set. The hydrochloric acid or sulfuric acid aqueous solution obtained by mixing in the second intermediate liquid storage device is pumped into the water inlet of the upper water distributor of the non-steady flow discrete stripping device; the stripping liquid droplets sprayed from the nozzle of the water spray pipe at the lower end of the water distributor are in a discrete dispersed phase state, and the number of droplets changes with the pulse frequency of the periodic variable frequency pulse pump, and the concentration of hydrochloric acid or sulfuric acid in the droplets changes with the concentration of hydrochloric acid or sulfuric acid in the second intermediate liquid storage device; the stripping liquid droplets moving in a discrete flow are in countercurrent contact with the alkali metal ion-loaded organic phase contained in the device from top to bottom, and finally, after being aggregated in the aqueous phase chamber at the bottom end of the non-steady flow discrete stripping device, they flow out from the bottom aqueous phase outlet to obtain a stripping raffinate; (2) continuously collecting the stripping raffinate flowing out of the aqueous phase outlet at the bottom end of the non-steady flow discrete stripping device in step (1) in batches; wherein the collection time of each batch is independently selected from 5 to 40 minutes, and respectively obtaining an enriched aqueous solution having a certain alkali metal ion concentration much higher than that of other coexisting alkali metal ions.

7. The method according to claim 6, wherein The preparation process of the loaded organic phase containing alkali metal ions after extraction in step (1) is as follows: t-BAMBP is dissolved in commercially available kerosene or xylene, and then the obtained organic solution containing the extractant is mixed with a mixed aqueous solution containing alkali metal ions at a volume ratio of 1:1 to 1:10 for 0.1 to 2 hours for extraction. After oil-water phase separation, the upper organic phase is collected to obtain the loaded organic phase containing alkali metal ions after extraction; the volume percentage of t-BAMBP in the kerosene or xylene organic solution of t-BAMBP is 10 to 30%; the loaded organic phase containing alkali metal ions contains at least three combinations of five alkali metal cations of lithium, sodium, potassium, rubidium, and cesium. The total concentration of alkali metal ions is 0.1~5g / L; the stripping solution is an aqueous solution of hydrochloric acid or sulfuric acid, wherein the molar concentration of hydrochloric acid or sulfuric acid continuously increases from 0.1mol / L to 2.0mol / L, and the increasing rate is 0.05~0.20mol / L per minute; the pulse frequency of the periodic variable frequency pulse pump increases periodically and continuously from 0.5Hz to 50Hz; the volume flow rate of the stripping solution ejected from the nozzle of the water spray pipe at the lower end of the water distributor increases periodically and continuously from 0.5mL / min to 5.0mL / min, the cycle value is one cycle every 1~10 minutes, and the flow rate increase rate in each cycle is 0.5~5.0mL per minute.

8. The method according to claim 6, wherein The stripping raffinate flowing out of the aqueous phase outlet at the bottom end of the non-steady flow discrete stripping device of step (1) is continuously collected in batches in step (2) by an automatic stepping collector of the second collecting device; the automatic stepping collector rotates in a constant speed step to perform continuous batch collection; wherein the time interval of the constant speed rotation of the automatic stepping collector is 5 to 40 minutes.

9. The method according to any one of claims 3 to 5, wherein The system for separating alkali metal ions by non-steady flow discrete extraction can be used alone or in multiple stages in series.

10. The method according to any one of claims 9, wherein: When multiple stages are connected in series, the volume flow rate of the mixed aqueous solution containing alkali metal ions pumped into the upper aqueous phase inlet of each stage of the non-steady flow discrete extraction device is controlled to be 1.0-100.0 mL / min; and the volume flow rate of the mixed aqueous solution containing alkali metal ions pumped into the upper aqueous phase inlet of each stage of the device is equal; The volume percentage of t-BAMBP in the extractant-containing organic solution pumped into the lower oil phase inlet of each stage of the non-steady flow discrete extraction device increases continuously from 1% to 30%, and the rate of increase increases step by step; the volume percentage of t-BAMBP in the organic solution pumped into the lower oil phase inlet of the downstream device is 1.0 to 3.0 times the rate of increase of the volume percentage of t-BAMBP in the organic solution pumped into the lower oil phase inlet of the upstream device.

11. The method according to claim 6 or 7, wherein: The non-steady flow discrete stripping system for separating alkali metal ions can be used alone or in multiple stages in series.

12. The method according to claim 11, wherein When multiple stages are connected in series, the volume flow rate of the alkali metal ion-loaded organic phase pumped into the lower oil phase inlet of each stage of the non-steady flow discrete stripping device is controlled to be 0.1-30.0 mL / min; and the volume flow rate of the alkali metal ion-loaded organic phase pumped into the lower oil phase inlet of each stage is equal; The concentration of hydrochloric acid or sulfuric acid in the stripping liquid pumped in from the water inlet of the upper water distributor of each stage of the non-steady flow discrete stripping device increases continuously from 0.1 mol / L to 2.0 mol / L, and the increasing rate is increased step by step; the increasing rate of the concentration of hydrochloric acid or sulfuric acid in the stripping liquid pumped in from the water inlet of the upper water distributor of the downstream device is 1.0 to 3.0 times the increasing rate of the concentration of hydrochloric acid or sulfuric acid in the stripping liquid pumped in from the water inlet of the upper water distributor of the upstream device.

13. A method for separating alkali metal ions by unsteady flow discrete flow chromatography using the systems of claims 1 and 2 in combination, characterized in that: When the non-steady flow discrete extraction and separation system for alkali metal ions and the non-steady flow discrete stripping and separation system for alkali metal ions are used in combination, the loaded organic phase flowing out of the oil phase overflow outlet at the top of the non-steady flow discrete extraction device is continuously pumped into the lower oil phase inlet of the non-steady flow discrete stripping device; The system for separating alkali metal ions by using the non-steady flow discrete extraction method comprises the following steps: (1-1) Pumping a mixed aqueous solution containing alkali metal ions from the upper aqueous phase inlet of the non-steady flow discrete extraction device at a pumping volume flow rate of 0.0 to 20.0 mL / min; the mixed aqueous solution containing alkali metal ions moves from top to bottom in the device and then flows out from the aqueous phase outlet at the lower portion of the non-steady flow discrete extraction device to obtain a raffinate aqueous phase; pumping an organic solvent from a first liquid replenishing device into a first intermediate liquid storage device with stirring, then closing the outlet valve of the first liquid replenishing device, and continuously pumping an organic extractant from a second liquid replenishing device into the first intermediate liquid storage device with stirring; At the same time, the periodic flow pump is turned on, and the periodic increase range and periodic value of the pumping flow rate are set. The organic solution containing the extractant obtained after mixing in the first intermediate liquid storage device is pumped into the oil chamber of the oil distributor from the oil phase inlet at the lower part of the non-steady flow discrete extraction device; then, air is pumped into the oil chamber of the oil distributor from the air inlet at the bottom end of the non-steady flow discrete extraction device; the oil droplets containing the extractant or the hollow oil droplets encapsulating bubbles ejected from the nozzle of the oil distributor nozzle are in a discrete dispersed phase state, and the number of oil droplets varies with the periodic flow rate of the periodic flow pump, and the concentration of the organic extractant in the oil droplets varies with the concentration of the extractant in the first intermediate liquid storage device; the oil droplets containing the extractant or the hollow oil droplets encapsulating bubbles moving in a discrete flow come into countercurrent contact with the mixed aqueous solution containing alkali metal ions contained in the device from bottom to top, and finally, after breaking and coalescing at the top porous bubble breaking baffle of the non-steady flow discrete extraction device, they flow out from the top oil phase overflow outlet to obtain a loaded organic phase; (1-2) continuously collecting in batches the loaded organic phase flowing out of the oil phase overflow outlet at the top of the non-steady flow discrete extraction device in step (1-1); wherein the collection time of each batch is independently selected from 5 to 40 minutes, and respectively obtaining an enriched organic phase having a loading concentration of a certain alkali metal ion much higher than that of other coexisting alkali metal ions; (1-3) The loaded organic phases obtained in step (1-2) and extracted with different alkali metal ions in different time periods are mixed with a hydrochloric acid or sulfuric acid aqueous solution with a concentration of 0.1 to 2.0 mol / L at a volume ratio of 1:1 to 10:1 for 0.1 to 2 hours for stripping; after oil-water separation, the lower aqueous phases are collected to obtain enriched aqueous solutions containing a certain alkali metal ion at a concentration much higher than that of other coexisting alkali metal ions; The system for separating alkali metal ions by using the non-steady flow discrete stripping method comprises the following steps: (2-1) The loaded organic phase containing alkali metal ions after extraction is pumped into the oil phase inlet at the lower part of the non-steady flow discrete stripping device, and the pumping volume flow rate is 0.0~20.0mL / min; the loaded organic phase containing alkali metal ions moves from bottom to top in the device, and then overflows from the oil phase overflow outlet at the top of the non-steady flow discrete stripping device to obtain the organic phase after stripping; pure water is pumped into the second intermediate liquid storage device with stirring from the third liquid replenishing device, and then the outlet valve of the third liquid replenishing device is closed, and commercially available hydrochloric acid or sulfuric acid is continuously pumped into the second intermediate liquid storage device with stirring from the fourth liquid replenishing device; at the same time, the periodic variable frequency pulse pump is turned on, and the periodic increase of the pulse frequency is set. Add range and period value, pump the hydrochloric acid or sulfuric acid aqueous solution obtained by mixing in the second intermediate liquid storage device from the water inlet of the upper water distributor of the non-steady flow discrete stripping device; the stripping liquid droplets sprayed from the nozzle of the water spray pipe at the lower end of the water distributor are in a discrete dispersed phase state, and the number of droplets changes with the pulse frequency of the periodic variable frequency pulse pump, and the concentration of hydrochloric acid or sulfuric acid in the droplets changes with the concentration of hydrochloric acid or sulfuric acid in the second intermediate liquid storage device; the stripping liquid droplets moving in a discrete flow are in countercurrent contact with the alkali metal ion-loaded organic phase contained in the device from top to bottom, and finally, after being aggregated in the water phase chamber at the bottom end of the non-steady flow discrete stripping device, flow out from the bottom water phase outlet to obtain a stripping raffinate; (2-2) Continuously collecting the stripping raffinate flowing out of the aqueous phase outlet at the bottom end of the non-steady flow discrete stripping device in step (2-1) in batches; wherein the collection time of each batch is independently selected from 5 to 40 minutes, and respectively obtaining an enriched aqueous solution having a certain alkali metal ion concentration much higher than that of other coexisting alkali metal ions.

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