Method for extracting and separating rubidium and cesium from crystallization mother liquor of lithium carbonate

Abstract

The invention belongs to the technical field of extraction and separation, and provides a method for extracting and separating rubidium and cesium from crystallization mother liquor of lithium carbonate, which comprises the following steps: (1) extraction, (2) washing or oil-water separation, (3) first reverse extraction, (4) second reverse extraction and (5) secondary washing or oil-water separation. A first stripping agent adopted in the first stripping process is prepared from sulfate, acid and water or / and first crystallization mother liquor, and in the first stripping agent, the concentration of the sulfate is 20-50 wt%, and the concentration of the acid is 1-15 wt%. A second stripping agent adopted in the second stripping process is prepared from acid and water or / and second crystallization mother liquor, and the concentration of the acid in the second stripping agent is 10-60 wt%. According to the method disclosed by the invention, the extraction and separation process for extracting rubidium and cesium can be simplified on the basis of ensuring high recovery rate of rubidium and cesium, and the cost for extracting and separating rubidium and cesium from the crystallization mother liquor of lithium carbonate is effectively reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of extraction and separation, and relates to a method for extracting and separating rubidium and cesium from a crystallization mother liquor of lithium carbonate. Background Art

[0002] Lithium is an important metal element, widely used in batteries, alloys, ceramics and other fields. One way to obtain lithium is to prepare lithium carbonate from ores and brines. In addition to lithium, ores and brines also contain other metal elements such as sodium, potassium, rubidium, cesium, etc.

[0003] Rubidium and cesium, as important scarce alkali metal resources, have unique physical and chemical properties and have important application value in strategic emerging industries such as aerospace, national defense, military industry and information technology. Due to the special scarcity of rubidium and cesium resources, their development and utilization methods are relatively complex. Currently, rubidium and cesium resources worldwide are mainly concentrated in a few countries and regions, and the industrial production process of rubidium and cesium is complex, with high separation costs and high energy consumption, resulting in expensive rubidium and cesium products. How to efficiently and low-costly separate high-purity rubidium and cesium products from the crystallization mother liquor of lithium carbonate formed by the production of lithium carbonate and achieve efficient resource utilization is one of the challenges currently faced by this field.

[0004] The main components of the crystallization mother liquor of lithium carbonate are sulfates of lithium, sodium, potassium, rubidium and cesium, among which sodium content is the highest, followed by potassium and lithium, and rubidium and cesium content is relatively less. In the prior art, the crystallization mother liquor of lithium carbonate obtained after lithium extraction is usually recycled by evaporation and concentration, but with the increase of the number of cycles, the elements such as rubidium and cesium therein are constantly accumulated, which not only has a negative impact on the quality of lithium carbonate products, but also rubidium and cesium therein are not utilized, resulting in a waste of rubidium and cesium resources. Since the chemical properties of rubidium and cesium are similar to lithium, sodium and potassium, it is difficult to separate rubidium and cesium from the crystallization mother liquor after lithium extraction.

[0005] Common methods for separating alkali metals mainly include: organic solvent extraction, chemical precipitation, ion exchange and membrane separation. The chemical precipitation method has low impurity removal efficiency and will introduce impurity ions, making subsequent separation difficult. The ion exchange method requires a large amount of resin and has a high cost for resin regeneration. The cost of the membrane separation method is relatively high. The organic solvent extraction method has low energy consumption, good separation effect, high recovery rate, high purity of the obtained product, and can be applied continuously, becoming the mainstream process for separating metal ions. At present, domestic and foreign researchers have conducted a lot of research on the extraction of rubidium and cesium metal ions by organic solvent extraction. Most of them are extracted from resources such as salt lakes, lithium mica and feldspar. There are still problems such as low recovery rate of rubidium and cesium, complex process, numerous steps and difficulty in classification.

[0006] For example, CN115180640A discloses a method for extracting rubidium and cesium salts from lithium extraction mother liquor of lepidolite. The method uses the solution after lithium extraction from lepidolite as raw material, firstly adopts freezing impurity removal and purification process to remove potassium and sodium impurity elements, then extracts the frozen potassium and sodium solution under alkaline conditions, then performs multi-stage water washing on the extracted organic phase solution containing rubidium and cesium under alkaline conditions, and finally performs back extraction on the washed organic phase solution containing rubidium and cesium under the condition of filling with high-purity carbon dioxide gas to form a weak acid environment, to obtain an aqueous solution containing rubidium and cesium, and obtains rubidium carbonate and cesium carbonate through filtration and drying. Before extraction, the method needs to freeze and cool the solution after lithium extraction from lepidolite until potassium and sodium crystals are precipitated, and then centrifuge to remove the crystallized potassium and sodium, thereby increasing the concentration of rubidium and cesium in the solution. However, the energy consumption of the freezing and cooling treatment is high, which is not conducive to reducing production costs. In the whole process of this method, the pH value of the system needs to be adjusted multiple times. For example, the pH value needs to be controlled at 12-14 in the extraction stage, the pH value of the organic phase feed liquid needs to be controlled at 7-10 in the multi-stage water washing stage, and the pH value needs to be controlled at 5-6 in the back extraction stage. Multiple adjustments to the pH value level of the system will increase the complexity of the operation. The operation of extracting rubidium and cesium by this method is not streamlined enough and the process flow is long, which will also lead to an increase in production costs and is not conducive to large-scale industrial production.

[0007] Therefore, there is an urgent need to develop a more efficient and process-simplified method for extracting and separating rubidium and cesium from the crystallization mother liquor of lithium carbonate, to streamline the extraction and separation process of rubidium and cesium while ensuring a high recovery rate of rubidium and cesium, and to reduce the difficulty and cost of extraction and separation of rubidium and cesium. Summary of the invention

[0008] In view of the problems of long process flow, complicated process and high production cost in the existing organic solvent extraction method for extracting rubidium and cesium from the crystallization mother liquor of lithium carbonate, the present invention provides a method for extracting and separating rubidium and cesium from the crystallization mother liquor of lithium carbonate, so as to simplify the extraction and separation process of rubidium and cesium on the basis of ensuring a high recovery rate of rubidium and cesium, and reduce the cost of extracting and separating rubidium and cesium from the crystallization mother liquor of lithium carbonate.

[0009] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is as follows:

[0010] A method for extracting and separating rubidium and cesium from a crystallization mother liquor of lithium carbonate comprises the following steps:

[0011] (1) Extraction process

[0012] An extractant is used to extract alkali metal ions in a crystallization mother liquor of lithium carbonate; the extractant is composed of a main extractant and a diluent, and the volume ratio of the main extractant to the diluent is (0.1-1): 1; during extraction, the extraction temperature is controlled to be 20-85°C and the phase ratio is (1-10): 1;

[0013] (2) Washing or oil-water separation process

[0014] The extract phase obtained in step (1) is washed with a first detergent to obtain a washed extract phase and a first washing residual liquid, and the first washing residual liquid is recycled as a first detergent, wherein the first detergent is water and / or the first washing residual liquid; or, the extract phase obtained in step (1) is subjected to oil-water separation by a separation device to remove the water phase entrained in the extract phase to obtain an extract phase after the water phase is separated;

[0015] (3) First stripping step

[0016] The first stripping agent is used to strip the washed extract phase obtained in step (2) or the extract phase after separation of the aqueous phase to obtain a first organic phase and a Cs-enriched phase. + first stripping solution; evaporating and concentrating the first stripping solution, cooling and crystallizing, and separating to obtain cesium double salt crystals and a first crystallization mother liquor, and using the first crystallization mother liquor to prepare a first stripping agent;

[0017] The first stripping agent is prepared from sulfate, acid and water or / and the first crystallization mother liquor. In the first stripping agent, the concentration of sulfate is 20 wt%~50 wt%, and the concentration of acid is 1 wt%~15 wt%. During stripping, the stripping temperature is controlled to be 20~85°C, and the ratio is (1~10): 1.

[0018] (4) Second stripping process

[0019] The first organic phase obtained in step (3) is stripped with a second stripping agent to obtain a second organic phase and Rb-enriched + adding sulfate to the second stripping solution until the concentration of sulfate is 20 wt% to 50 wt%, cooling and crystallizing, separating, obtaining rubidium double salt crystals and a second crystallization mother liquor, and using the second crystallization mother liquor to prepare a second stripping agent;

[0020] The second stripping agent is prepared from acid and water or / and the second crystallization mother liquor, and the acid concentration in the second stripping agent is 10 wt%~60 wt%; during stripping, the stripping temperature is controlled to be 25~65 °C, and the ratio is (1~10): 1;

[0021] (5) Second washing or oil-water separation process

[0022] The second organic phase obtained in step (4) is washed with a second washing agent to obtain a regenerated extractant and a second washing residual liquid, and the obtained second washing residual liquid is used to prepare a second washing agent; the second washing agent is prepared from an acid and water or / and the second washing residual liquid, and the concentration of the acid in the second washing agent is 1 wt% to 10 wt%;

[0023] Alternatively, the second organic phase obtained in step (4) is subjected to oil-water separation by a separation device, and the water phase entrained in the second organic phase is removed to obtain a regenerated extractant; and the regenerated extractant is returned to step (1) for recycling.

[0024] In steps (3) to (4) of the above technical solution, the sulfate is ferric sulfate, ferrous sulfate, manganese sulfate, ammonium sulfate, aluminum sulfate or magnesium sulfate.

[0025] In steps (3) to (5) of the above technical solution, the acid includes at least one of sulfuric acid, hydrochloric acid, nitric acid, oxalic acid, phosphoric acid, acetic acid and citric acid.

[0026] In step (3) of the above technical solution, the cesium complex salt crystals are cesium sulfate complex salt crystals. The specific type of cesium sulfate complex salt varies according to the type of sulfate selected in step (3). For example, the cesium complex salt crystals can be cesium aluminum sulfate crystals, cesium magnesium sulfate crystals, cesium manganese sulfate crystals, etc.

[0027] In step (4) of the above technical solution, the rubidium complex salt crystals are rubidium sulfate complex salt crystals. The specific type of rubidium sulfate complex salt varies according to the type of sulfate selected in step (4). For example, the rubidium complex salt crystals can be aluminum sulfate rubidium crystals, magnesium sulfate rubidium crystals, manganese sulfate rubidium crystals, etc.

[0028] In step (3) of the above technical solution, when the reaction just starts running, no first crystallization mother liquor is produced, and the first stripping agent is prepared from sulfate, acid and water. After the reaction runs until the first crystallization mother liquor is produced, the first stripping agent is prepared from sulfate, acid and the first crystallization mother liquor, or the first stripping agent is prepared from sulfate, acid, the first crystallization mother liquor and water.

[0029] In step (4) of the above technical solution, when the reaction just starts running, no second crystallization mother liquor is produced, and the second stripping agent is prepared from acid and water. After the reaction is run until the second crystallization mother liquor is produced, the second stripping agent is prepared from acid and the second crystallization mother liquor, or the second stripping agent is prepared from acid, the second crystallization mother liquor and water.

[0030] In step (5) of the above technical solution, when the second organic phase obtained in step (4) is washed with a second detergent, no second washing residual liquid is produced when the reaction just starts, and the second detergent is prepared from acid and water. After the reaction is carried out until the second washing residual liquid is produced, the second detergent is prepared from acid and the second washing residual liquid, or the second detergent is prepared from acid, the second washing residual liquid and water.

[0031] In step (1) of the above technical solution, the main extractant and diluent used can be determined by referring to the prior art. Usually, the main extractant is 4-tert-butyl-2-(α-methylbenzyl)phenol, di(2-ethylhexyl)phosphate, 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester, di(2,4,4-trimethylpentyl)phosphorous acid, dinonylnaphthalenesulfonic acid, cycloalkane acid or tert-carbonic acid. Usually, the diluent is at least one of sulfonated kerosene, n-hexane, octane, cyclohexane, decane, nonane, n-heptane, dodecane, solvent oil, xylene, diethylbenzene, carbon tetrachloride, benzene and petroleum ether.

[0032] In step (1) of the above technical solution, the extraction method adopted is multi-stage countercurrent extraction. Furthermore, the number of stages of the multi-stage countercurrent extraction is 1 to 5, and the number of levels of each stage is 1 to 5. In practical applications, the number of stages and levels of the countercurrent extraction are determined according to the composition and content of the lithium carbonate crystallization mother liquor. Furthermore, the number of stages of the multi-stage countercurrent extraction is preferably 3, and the number of levels of each stage is preferably 3.

[0033] In steps (3) to (4) of the above technical solution, the stripping method adopted is countercurrent stripping of several sections and stages, and the number of sections of the countercurrent stripping of several sections and stages is 1 to 5 sections, and the number of stages in each section is 1 to 5 levels. The number of sections and stages adopted for the countercurrent stripping can be determined according to actual application requirements. Preferably, the number of sections of the countercurrent stripping of several sections and stages is preferably 3 sections, and the number of stages in each section is preferably 3 levels.

[0034] In step (2) and step (5) of the above technical solution, when a separation device is used for oil-water separation, the separation device used is an oil-water separation device commonly used in the field of extraction separation, including but not limited to a coalescing separator, a disc centrifuge, etc. The operating parameters used when using a separation device for oil-water separation can be determined according to the actual application requirements and with reference to the prior art. For example, when a coalescing separator is used for oil-water separation, the separation temperature can be controlled to be 20-40°C, the flow rate of the polycrystallization separator can be controlled to be 200-500 m³ / h, the working pressure of the polycrystallization separator can be controlled to be 0.4-0.7 MPa, and the working pressure difference can be controlled to be 0.15 MPa. For another example, when a disc centrifuge is used for oil-water separation, the centrifugal temperature can be controlled to be 20-35°C, the speed of the disc centrifuge can be controlled to be 300-2000 r / min, and the separation time can be 1-10 min.

[0035] In the above technical scheme, when the first detergent is used to wash the extract phase obtained in step (1) in step (2), the washing temperature is controlled to be 20~85°C and the phase ratio is (1~10):1; when the second detergent is used to wash the second organic phase obtained in step (4) in step (5), the washing temperature is controlled to be 25~65°C and the phase ratio is (1~10):1.

[0036] In the above technical solution, in step (2) and step (5), the washing method adopted during washing is multi-stage countercurrent washing. Further, the number of stages in the multi-stage countercurrent washing is 1 to 3, and the number of levels in each stage is 1 to 3.

[0037] In step (3) and step (4) of the above technical solution, during cooling crystallization, the solution to be crystallized can usually be cooled to 5-30°C for crystallization, and the crystallization time can be controlled to be 1-3 hours.

[0038] Compared with the prior art, the technical solution provided by the present invention produces the following beneficial technical effects:

[0039] 1. The present invention provides a method for extracting and separating rubidium and cesium from a crystallization mother liquor of lithium carbonate, the method comprising extraction, washing or oil-water separation, a first stripping, a second stripping and a second washing or oil-water separation process. The key to the method is that in the first stripping step, sulfate and acid are combined in an appropriate ratio and concentration as the first stripping agent. In a solution environment containing a high concentration of sulfate, only a small amount of cesium ions are needed to allow the cesium ions to precipitate in the form of cesium sulfate complex salt crystals, thereby improving the stripping effect on the cesium ions; at the same time, in the first stripping step, the acid of appropriate concentration in the first stripping agent can strip out the impurity ions in the extraction phase after washing or the extraction phase after the aqueous phase is separated, thereby reducing the content of impurity ions in the first organic phase; after the first organic phase is stripped with a second stripping agent, the acid in the second stripping agent can further strip out the impurity ions in the first organic phase, further reducing the content of impurity ions in the subsequently obtained regenerated extractant, and improving the recycling performance of the extractant; because the first stripping step improves the stripping effect on the cesium ions, as many cesium ions as possible are stripped out, thereby reducing the difficulty of stripping rubidium ions in the second stripping step. On this basis, through the coordination of process operations and process parameters in each process, the method of the present invention effectively improves the extraction and separation effect of cesium and rubidium by adopting a more streamlined process than the prior art. Compared with the existing organic extraction process for extracting rubidium and cesium from the crystallization mother liquor of lithium carbonate, the process of the method of the present invention is simpler, the process flow is shorter, and there is no need to adjust the pH value of the reaction system in different processes multiple times or specifically, and there is no need for high-energy consumption operations such as freezing, which can effectively reduce the difficulty and cost of cascade classification recovery of cesium and rubidium from the crystallization mother liquor of lithium carbonate, and is conducive to promotion and application in engineering practice.

[0040] 2. The present invention is verified by experiments: after continuous operation for 1 day, the extraction rate of cesium and rubidium, the stripping rate of cesium and rubidium, and the recovery rate of cesium and rubidium by the method of the present invention are all above 98%. At the same time, the purity of the cesium double salt crystals and rubidium double salt crystals obtained in Examples 1 to 8 are all above 98%. In addition, after continuous operation for 1 day in Examples 1 to 8, the extraction rate, stripping rate, recovery rate of cesium and rubidium, and the purity of the obtained rubidium double salt crystals and cesium double salt crystals are all about 10% higher than the data of the comparative example 1 which is continuously operated for 10 hours. It shows that the method of the present invention has more excellent long-term operation stability, and the method of the present invention realizes efficient resource utilization of the crystallization mother liquor of lithium carbonate through a simpler process. DETAILED DESCRIPTION

[0041] The following examples further illustrate the method for extracting and separating rubidium and cesium from the crystallization mother liquor of lithium carbonate provided by the present invention.

[0042] In the following embodiments, 4-tert-butyl-2-(α-methylbenzyl)phenol (t-BAMBP) is used as the main extractant to illustrate the extraction process of the present invention. In practical applications, the selection of the main extractant is not limited to t-BAMBP, and other main extractants used in the prior art to extract rubidium and cesium by organic solvent extraction can also be used.

[0043] In the following examples and comparative examples, the phase ratio (O / A) refers to the ratio of the organic phase volume to the aqueous phase volume.

[0044] In the following examples and comparative examples, the crystallization mother liquor of lithium carbonate is derived from the crystallization mother liquor after lithium extraction from ore, and the metal ions contained therein are mainly Na + , K + , Li + , Rb + , Cs + , Ca 2+ , Fe 3+ , the anions it contains are mainly SO4 2- and Cl - , the element content of the crystallization mother liquor of lithium carbonate is shown in Table 1:

[0045] Table 1 Element content of lithium carbonate crystallization mother liquor

[0046] element Na K R Cs Mg Ca Fe Content (g / L) 107 30.99 2.53 0.93 0.0031 0.87 0.33 element B Li Zn Cu <![CDATA[SO4 2- ]]> <![CDATA[Cl - ]]> Content (g / L) 5.83 9.14 0.0012 0.0028 220 41.35

[0047] Example 1

[0048] In this embodiment, a method for extracting and separating rubidium and cesium from a crystallization mother liquor of lithium carbonate is provided, and the steps are as follows:

[0049] (1) Extraction process

[0050] The extractant and the crystallization mother liquor of lithium carbonate are added into a centrifugal extractor, and the alkali metal ions in the crystallization mother liquor of lithium carbonate are subjected to five-stage three-stage countercurrent extraction, and the alkali metal ions in the crystallization mother liquor of lithium carbonate are transferred to the extractant to obtain an extraction phase and a raffinate phase.

[0051] The extractant consists of a main extractant and a diluent, the main extractant is t-BAMBP, the diluent is sulfonated kerosene, and the volume ratio of the main extractant to the diluent is 0.3:1; during extraction, the extraction temperature of each section is controlled to be 60°C and the phase ratio (O / A) is 4:1.

[0052] (2) Oil-water separation process

[0053] The extract phase obtained in step (1) is subjected to oil-water separation by a coalescing separator, and the water phase entrained in the extract phase is removed to obtain an extract phase after the water phase is separated. During the oil-water separation, the separation temperature is controlled to be 20°C, the flow rate of the coalescing separator is controlled to be 200 m³ / h, the working pressure is controlled to be 0.4 MPa, and the working pressure difference is controlled to be 0.15 MPa.

[0054] (3) First stripping step

[0055] The first stripping agent and the extract phase obtained after separation of the aqueous phase in step (2) are added to a centrifugal extractor for two-stage three-stage countercurrent stripping to obtain a first organic phase and a Cs-enriched phase. + The first stripping solution is evaporated and concentrated to a saturated state, then cooled to 30°C, crystallized for 3 hours, separated, and magnesium cesium sulfate crystals and a first crystallization mother liquor are obtained, and the first crystallization mother liquor is used to prepare a first stripping agent.

[0056] When the reaction just starts running, no first crystallization mother liquor is produced, and the first stripping agent is prepared from magnesium sulfate, sulfuric acid and deionized water. After the reaction runs until the first crystallization mother liquor is produced, the first stripping agent is prepared from magnesium sulfate, sulfuric acid and the first crystallization mother liquor, or the first stripping agent is prepared from magnesium sulfate, sulfuric acid, the first crystallization mother liquor and deionized water, in which the concentration of magnesium sulfate is 35 wt%, and the concentration of sulfuric acid is 1 wt%. During stripping, the stripping temperature of each section is controlled to be 30°C and the phase ratio (O / A) is 1:1.

[0057] (4) Second stripping process

[0058] The second stripping agent and the first organic phase obtained in step (3) are added to a centrifugal extractor for three-stage three-stage countercurrent stripping to obtain a second organic phase and Rb-enriched + A second stripping solution; adding aluminum sulfate to the second stripping solution and fully dissolving it to make the concentration of aluminum sulfate 30 wt%, then cooling to 30 ° C, crystallizing for 3 h, separating, obtaining aluminum sulfate rubidium crystals and a second crystallization mother liquor, and using the second crystallization mother liquor to prepare a second stripping agent.

[0059] When the reaction just starts running, no second crystallization mother liquor is produced, and the second stripping agent is prepared from sulfuric acid and deionized water. After the reaction runs until the second crystallization mother liquor is produced, the second stripping agent is prepared from sulfuric acid and the second crystallization mother liquor, or the second stripping agent is prepared from sulfuric acid, the second crystallization mother liquor and deionized water, and the concentration of sulfuric acid in the second stripping agent is 30 wt%; during stripping, the stripping temperature of each section is controlled to be 30°C and the phase ratio (O / A) is 1:1.

[0060] (5) Washing process

[0061] The second detergent and the second organic phase obtained in step (4) are added to a centrifugal extractor, and the second organic phase is subjected to a two-stage countercurrent washing to obtain a regenerated extractant and a second washing raffinate, and the obtained second washing raffinate is used to prepare a second detergent. The regenerated extractant is returned to step (1) for recycling.

[0062] When the reaction just starts running, no second washing residual liquid is produced, and the second washing agent is prepared from sulfuric acid and deionized water. After the reaction runs until the second washing residual liquid is produced, the second washing agent is prepared from sulfuric acid and the second washing residual liquid, or the second washing agent is prepared from sulfuric acid, the second washing residual liquid and deionized water, and the concentration of sulfuric acid in the second washing agent is 6wt%. During washing, the washing temperature is controlled to be 30°C, and the ratio (O / A) is 1:1.

[0063] Example 2

[0064] In this embodiment, a method for extracting and separating rubidium and cesium from a crystallization mother liquor of lithium carbonate is provided, and the steps are as follows:

[0065] (1) Extraction process

[0066] The extractant and the crystallization mother liquor of lithium carbonate are added into a centrifugal extractor, and the alkali metal ions in the crystallization mother liquor of lithium carbonate are subjected to a three-stage countercurrent extraction, and the alkali metal ions in the crystallization mother liquor of lithium carbonate are transferred to the extractant to obtain an extraction phase and a raffinate phase.

[0067] The extractant consists of a main extractant and a diluent, the main extractant is t-BAMBP, the diluent is xylene, and the volume ratio of the main extractant to the diluent is 1:1; during extraction, the extraction temperature is controlled to be 85°C and the phase ratio (O / A) is 6:1.

[0068] (2) Oil-water separation process

[0069] The extract phase obtained in step (1) is subjected to oil-water separation by a disc centrifuge, and the water phase entrained in the extract phase is removed to obtain an extract phase after the water phase is separated. During the oil-water separation, the separation temperature is controlled to be 35°C, the rotation speed of the disc centrifuge is controlled to be 300r / min, and the separation time is controlled to be 10 min.

[0070] (3) First stripping step

[0071] The first stripping agent and the extract phase obtained after separation of the aqueous phase in step (2) are added to a centrifugal extractor for a three-stage countercurrent stripping to obtain a first organic phase and a Cs-enriched phase. + The first stripping solution is evaporated and concentrated to a saturated state, then cooled to 20°C, crystallized for 3 hours, separated, and cesium aluminum sulfate crystals and a first crystallization mother liquor are obtained, and the first crystallization mother liquor is used to prepare a first stripping agent.

[0072] When the reaction just starts running, no first crystallization mother liquor is produced, and the first stripping agent is prepared from aluminum sulfate, sulfuric acid and deionized water. After the reaction runs until the first crystallization mother liquor is produced, the first stripping agent is prepared from aluminum sulfate, sulfuric acid and the first crystallization mother liquor, or the first stripping agent is prepared from aluminum sulfate, sulfuric acid, the first crystallization mother liquor and deionized water, in which the concentration of aluminum sulfate and the concentration of sulfuric acid are 50 wt% and 10 wt% respectively. During stripping, the stripping temperature is controlled to be 50°C and the phase ratio (O / A) is 3:1.

[0073] (4) Second stripping process

[0074] The second stripping agent and the first organic phase obtained in step (3) are added to a centrifugal extractor for a three-stage countercurrent stripping to obtain a second organic phase and Rb-enriched + to the second stripping solution, add ferric sulfate and fully dissolve it to make the concentration of ferric sulfate be 20 wt%, then cool to 25 ° C, crystallize for 1 hour, separate, and obtain ferric sulfate rubidium crystals and a second crystallization mother liquor, and use the second crystallization mother liquor to prepare a second stripping agent.

[0075] When the reaction just starts running, no second crystallization mother liquor is produced, and the second stripping agent is prepared from sulfuric acid and deionized water. After the reaction runs until the second crystallization mother liquor is produced, the second stripping agent is prepared from sulfuric acid and the second crystallization mother liquor, or the second stripping agent is prepared from sulfuric acid, the second crystallization mother liquor and deionized water, and the concentration of sulfuric acid in the second stripping agent is 40 wt%; during stripping, the stripping temperature is controlled to be 65°C and the phase ratio (O / A) is 6:1.

[0076] (5) Washing process

[0077] The second detergent and the second organic phase obtained in step (4) are added to a centrifugal extractor, and the second organic phase is subjected to a two-stage countercurrent washing to obtain a regenerated extractant and a second washing raffinate, and the obtained second washing raffinate is used to prepare a second detergent. The regenerated extractant is returned to step (1) for recycling.

[0078] When the reaction just starts running, no second washing residual liquid is produced, and the second detergent is prepared from sulfuric acid and deionized water. After the reaction runs until the second washing residual liquid is produced, the second detergent is prepared from sulfuric acid and the second washing residual liquid, or the second detergent is prepared from sulfuric acid, the second washing residual liquid and deionized water, and the concentration of sulfuric acid in the second detergent is 6wt%. During washing, the washing temperature is controlled to be 25°C, and the ratio (O / A) is 4:1.

[0079] Example 3

[0080] In this embodiment, a method for extracting and separating rubidium and cesium from a crystallization mother liquor of lithium carbonate is provided, and the steps are as follows:

[0081] (1) Extraction process

[0082] The extractant and the crystallization mother liquor of lithium carbonate are added into a centrifugal extractor, and the alkali metal ions in the crystallization mother liquor of lithium carbonate are subjected to two-stage three-stage countercurrent extraction, and the alkali metal ions in the crystallization mother liquor of lithium carbonate are transferred to the extractant to obtain an extraction phase and a raffinate phase.

[0083] The extractant consists of a main extractant and a diluent, the main extractant is t-BAMBP, the diluent is dodecane, and the volume ratio of the main extractant to the diluent is 0.1:1; during extraction, the extraction temperature of each section is controlled to be 55°C and the phase ratio (O / A) is 10:1.

[0084] (2) Washing process

[0085] The first detergent and the extract phase obtained in step (1) are added to a centrifugal extractor, and the extract phase is subjected to a three-stage countercurrent washing to obtain the washed extract phase and the first washing residual liquid, and the obtained first washing residual liquid is recycled as the first detergent, wherein the first detergent is deionized water or / and the first washing residual liquid. During washing, the washing temperature is controlled to be 85°C, and the phase ratio (O / A) is 5:1.

[0086] (3) First stripping step

[0087] The first stripping agent and the washed extract phase obtained in step (2) are added to a centrifugal extractor for two-stage three-stage countercurrent stripping to obtain a first organic phase and a Cs-enriched phase. + The first stripping solution is evaporated and concentrated to a saturated state, then cooled to 20°C, crystallized for 2 hours, separated, and magnesium cesium sulfate crystals and a first crystallization mother liquor are obtained, and the first crystallization mother liquor is used to prepare a first stripping agent.

[0088] When the reaction just starts running, no first crystallization mother liquor is produced, and the first stripping agent is prepared from magnesium sulfate, sulfuric acid and deionized water. After the reaction runs until the first crystallization mother liquor is produced, the first stripping agent is prepared from magnesium sulfate, sulfuric acid and the first crystallization mother liquor, or the first stripping agent is prepared from magnesium sulfate, sulfuric acid, the first crystallization mother liquor and deionized water, in which the concentration of magnesium sulfate is 20 wt%, and the concentration of sulfuric acid is 5 wt%. During stripping, the stripping temperature of each section is controlled to be 85°C and the phase ratio (O / A) is 3:1.

[0089] (4) Second stripping process

[0090] The second stripping agent and the first organic phase obtained in step (3) are added to a centrifugal extractor for two-stage three-stage countercurrent stripping to obtain a second organic phase and Rb-enriched + A second stripping solution is prepared; aluminum sulfate is added to the second stripping solution and fully dissolved to a concentration of 35 wt% of aluminum sulfate, and then cooled to 25 ° C, crystallized for 2 h, separated, and aluminum sulfate rubidium crystals and a second crystallization mother liquor are obtained, and the second crystallization mother liquor is used to prepare a second stripping agent.

[0091] When the reaction just starts running, no second crystallization mother liquor is produced, and the second stripping agent is prepared from sulfuric acid and deionized water. After the reaction runs until the second crystallization mother liquor is produced, the second stripping agent is prepared from sulfuric acid and the second crystallization mother liquor, or the second stripping agent is prepared from sulfuric acid, the second crystallization mother liquor and deionized water, and the concentration of sulfuric acid in the second stripping agent is 40 wt%; during stripping, the stripping temperature of each section is controlled to be 40°C and the phase ratio (O / A) is 2:1.

[0092] (5) Second washing process

[0093] The second detergent and the second organic phase obtained in step (4) are added to a centrifugal extractor, and the second organic phase is subjected to three-stage two-stage countercurrent washing to obtain a regenerated extractant and a second washing residual liquid, and the obtained second washing residual liquid is used to prepare a second detergent. The regenerated extractant is returned to step (1) for recycling.

[0094] When the reaction just starts running, no second washing residual liquid is produced, and the second detergent is prepared from sulfuric acid and deionized water. After the reaction runs until the second washing residual liquid is produced, the second detergent is prepared from sulfuric acid and the second washing residual liquid, or the second detergent is prepared from sulfuric acid, the second washing residual liquid and deionized water, and the concentration of sulfuric acid in the second detergent is 10wt%. During washing, the washing temperature of each section is controlled to be 25℃, and the ratio (O / A) is 10:1.

[0095] Example 4

[0096] In this embodiment, a method for extracting and separating rubidium and cesium from a crystallization mother liquor of lithium carbonate is provided, and the steps are as follows:

[0097] (1) Extraction process

[0098] The extractant and the crystallization mother liquor of lithium carbonate are added into a centrifugal extractor, and the alkali metal ions in the crystallization mother liquor of lithium carbonate are subjected to three-stage three-level countercurrent extraction, and the alkali metal ions in the crystallization mother liquor of lithium carbonate are transferred to the extractant to obtain an extraction phase and a raffinate phase.

[0099] The extractant consists of a main extractant and a diluent, the main extractant is t-BAMBP, the diluent is n-hexane, and the volume ratio of the main extractant to the diluent is 0.7:1; during extraction, the extraction temperature of each section is controlled to be 45°C and the phase ratio (O / A) is 4:1.

[0100] (2) Washing process

[0101] The first detergent and the extract phase obtained in step (1) are added to a centrifugal extractor, and the extract phase is subjected to three-stage three-stage countercurrent washing to obtain the washed extract phase and the first washing residual liquid, and the obtained first washing residual liquid is recycled as the first detergent, wherein the first detergent is deionized water or / and the first washing residual liquid. During washing, the washing temperature of each stage is controlled to be 20°C, and the phase ratio (O / A) is 10:1.

[0102] (3) First stripping step

[0103] The first stripping agent and the washed extract phase obtained in step (2) are added to a centrifugal extractor for three-stage three-stage countercurrent stripping to obtain a first organic phase and a Cs-enriched phase. + The first stripping solution; the first stripping solution is evaporated and concentrated to a saturated state, then cooled to 15°C, crystallized for 2 hours, separated, and cesium aluminum sulfate crystals and a first crystallization mother liquor are obtained, and the first crystallization mother liquor is used to prepare a first stripping agent.

[0104] When the reaction just starts running, no first crystallization mother liquor is produced, and the first stripping agent is prepared from aluminum sulfate, sulfuric acid and deionized water. After the reaction runs until the first crystallization mother liquor is produced, the first stripping agent is prepared from aluminum sulfate, sulfuric acid and the first crystallization mother liquor, or the first stripping agent is prepared from aluminum sulfate, sulfuric acid, the first crystallization mother liquor and deionized water, in which the concentration of aluminum sulfate and the concentration of sulfuric acid are 40 wt% and 15 wt% respectively. During stripping, the stripping temperature of each section is controlled to be 20°C and the phase ratio (O / A) is 5:1.

[0105] (4) Second stripping process

[0106] The second stripping agent and the first organic phase obtained in step (3) are added to a centrifugal extractor for two-stage three-stage countercurrent stripping to obtain a second organic phase and Rb-enriched + to the second stripping solution; adding manganese sulfate to the second stripping solution and fully dissolving it to make the concentration of manganese sulfate 40 wt%, then cooling to 15 ° C, crystallizing for 2 h, separating, obtaining manganese sulfate rubidium crystals and a second crystallization mother liquor, and using the second crystallization mother liquor to prepare a second stripping agent.

[0107] When the reaction just starts running, no second crystallization mother liquor is produced, and the second stripping agent is prepared from sulfuric acid and deionized water. After the reaction runs until the second crystallization mother liquor is produced, the second stripping agent is prepared from sulfuric acid and the second crystallization mother liquor, or the second stripping agent is prepared from sulfuric acid, the second crystallization mother liquor and deionized water, and the concentration of sulfuric acid in the second stripping agent is 60 wt%; during stripping, the stripping temperature of each section is controlled to be 40°C and the phase ratio (O / A) is 8:1.

[0108] (5) Second washing process

[0109] The second detergent and the second organic phase obtained in step (4) are added to a centrifugal extractor, and the second organic phase is subjected to a two-stage countercurrent washing to obtain a regenerated extractant and a second washing raffinate, and the obtained second washing raffinate is used to prepare a second detergent. The regenerated extractant is returned to step (1) for recycling.

[0110] When the reaction just starts running, no second washing residual liquid is produced, and the second washing agent is prepared from sulfuric acid and deionized water. After the reaction runs until the second washing residual liquid is produced, the second washing agent is prepared from sulfuric acid and the second washing residual liquid, or the second washing agent is prepared from sulfuric acid, the second washing residual liquid and deionized water, and the concentration of sulfuric acid in the second washing agent is 1wt%. During washing, the washing temperature is controlled to be 65°C, and the ratio (O / A) is 6:1.

[0111] Example 5

[0112] In this embodiment, a method for extracting and separating rubidium and cesium from a crystallization mother liquor of lithium carbonate is provided, and the steps are as follows:

[0113] (1) Extraction process

[0114] The extractant and the crystallization mother liquor of lithium carbonate are added into a centrifugal extractor, and the alkali metal ions in the crystallization mother liquor of lithium carbonate are subjected to three-stage three-level countercurrent extraction, and the alkali metal ions in the crystallization mother liquor of lithium carbonate are transferred to the extractant to obtain an extraction phase and a raffinate phase.

[0115] The extractant consists of a main extractant and a diluent, the main extractant is t-BAMBP, the diluent is cyclohexane, and the volume ratio of the main extractant to the diluent is 0.4:1; during extraction, the extraction temperature of each section is controlled to be 20°C and the phase ratio (O / A) is 2:1.

[0116] (2) Washing process

[0117] The first detergent and the extract phase obtained in step (1) are added to a centrifugal extractor, and the extract phase is subjected to three-stage three-stage countercurrent washing to obtain the washed extract phase and the first washing residual liquid, and the obtained first washing residual liquid is recycled as the first detergent, wherein the first detergent is deionized water or / and the first washing residual liquid. During washing, the washing temperature of each stage is controlled to be 30°C, and the phase ratio (O / A) is 4:1.

[0118] (3) First stripping step

[0119] The first stripping agent and the washed extract phase obtained in step (2) are added to a centrifugal extractor for two-stage three-stage countercurrent stripping to obtain a first organic phase and a Cs-enriched phase. + The first stripping solution is evaporated and concentrated to a saturated state, then cooled to 10°C, crystallized for 2 hours, separated, and magnesium cesium sulfate crystals and a first crystallization mother liquor are obtained, and the first crystallization mother liquor is used to prepare a first stripping agent.

[0120] When the reaction just starts running, no first crystallization mother liquor is produced, and the first stripping agent is prepared from magnesium sulfate, sulfuric acid and deionized water. After the reaction runs until the first crystallization mother liquor is produced, the first stripping agent is prepared from magnesium sulfate, sulfuric acid and the first crystallization mother liquor, or the first stripping agent is prepared from magnesium sulfate, sulfuric acid, the first crystallization mother liquor and deionized water, in which the concentration of magnesium sulfate and the concentration of sulfuric acid are 45 wt% and 10 wt% respectively. During stripping, the stripping temperature of each section is controlled to be 40°C and the phase ratio (O / A) is 10:1.

[0121] (4) Second stripping process

[0122] The second stripping agent and the first organic phase obtained in step (3) are added to a centrifugal extractor for two-stage three-stage countercurrent stripping to obtain a second organic phase and Rb-enriched + A second stripping solution is prepared; aluminum sulfate is added to the second stripping solution and fully dissolved to make the concentration of aluminum sulfate 50 wt%, then cooled to 5 ° C, crystallized for 2 h, separated, and aluminum sulfate rubidium crystals and a second crystallization mother liquor are obtained, and the second crystallization mother liquor is used to prepare a second stripping agent.

[0123] When the reaction just starts running, no second crystallization mother liquor is produced, and the second stripping agent is prepared from sulfuric acid and deionized water. After the reaction runs until the second crystallization mother liquor is produced, the second stripping agent is prepared from sulfuric acid and the second crystallization mother liquor, or the second stripping agent is prepared from sulfuric acid, the second crystallization mother liquor and deionized water, and the concentration of sulfuric acid in the second stripping agent is 25 wt%; during stripping, the stripping temperature of each section is controlled to be 25°C and the phase ratio (O / A) is 4:1.

[0124] (5) Oil-water separation process

[0125] The second organic phase obtained in step (4) is subjected to oil-water separation by a disc centrifuge, and the water phase entrained in the second organic phase is removed to obtain a regenerated extractant, which is then returned to step (1) for recycling. During the oil-water separation, the separation temperature is controlled to be 25°C, the rotation speed of the disc centrifuge is controlled to be 300 r / min, and the separation time is 5 min.

[0126] Example 6

[0127] In this embodiment, a method for extracting and separating rubidium and cesium from a crystallization mother liquor of lithium carbonate is provided, and the steps are as follows:

[0128] (1) Extraction process

[0129] The extractant and the crystallization mother liquor of lithium carbonate are added into a centrifugal extractor, and the alkali metal ions in the crystallization mother liquor of lithium carbonate are subjected to three-stage three-level countercurrent extraction, and the alkali metal ions in the crystallization mother liquor of lithium carbonate are transferred to the extractant to obtain an extraction phase and a raffinate phase.

[0130] The extractant consists of a main extractant and a diluent, the main extractant is t-BAMBP, the diluent is sulfonated kerosene, and the volume ratio of the main extractant to the diluent is 0.3:1; during extraction, the extraction temperature of each section is controlled to be 55°C and the phase ratio (O / A) is 3:1.

[0131] (2) Washing process

[0132] The first detergent and the extract phase obtained in step (1) are added to a centrifugal extractor, and the extract phase is subjected to three-stage three-stage countercurrent washing to obtain the washed extract phase and the first washing residual liquid, and the obtained first washing residual liquid is recycled as the first detergent, wherein the first detergent is deionized water or / and the first washing residual liquid. During washing, the washing temperature of each stage is controlled to be 40°C, and the phase ratio (O / A) is 1:1.

[0133] (3) First stripping step

[0134] The first stripping agent and the washed extract phase obtained in step (2) are added to a centrifugal extractor for two-stage three-stage countercurrent stripping to obtain a first organic phase and a Cs-enriched phase. + The first stripping solution is evaporated and concentrated to a saturated state, then cooled to 10°C, crystallized for 2 hours, separated, and magnesium cesium sulfate crystals and a first crystallization mother liquor are obtained, and the first crystallization mother liquor is used to prepare a first stripping agent.

[0135] When the reaction just starts running, no first crystallization mother liquor is produced, and the first stripping agent is prepared from magnesium sulfate, sulfuric acid and deionized water. After the reaction runs until the first crystallization mother liquor is produced, the first stripping agent is prepared from magnesium sulfate, sulfuric acid and the first crystallization mother liquor, or the first stripping agent is prepared from magnesium sulfate, sulfuric acid, the first crystallization mother liquor and deionized water, in which the concentration of magnesium sulfate is 40 wt%, and the concentration of sulfuric acid is 5 wt%. During stripping, the stripping temperature of each section is controlled to be 40°C and the phase ratio (O / A) is 10:1.

[0136] (4) Second stripping process

[0137] The second stripping agent and the first organic phase obtained in step (3) are added to a centrifugal extractor for two-stage three-stage countercurrent stripping to obtain a second organic phase and Rb-enriched + to the second stripping solution, adding magnesium sulfate and fully dissolving it to make the concentration of magnesium sulfate be 35 wt%, then cooling to 5 ° C, crystallizing for 2 h, separating, obtaining magnesium sulfate rubidium crystals and a second crystallization mother liquor, and using the second crystallization mother liquor to prepare a second stripping agent.

[0138] When the reaction just starts running, no second crystallization mother liquor is produced, and the second stripping agent is prepared from sulfuric acid and deionized water. After the reaction runs until the second crystallization mother liquor is produced, the second stripping agent is prepared from sulfuric acid and the second crystallization mother liquor, or the second stripping agent is prepared from sulfuric acid, the second crystallization mother liquor and deionized water, and the concentration of sulfuric acid in the second stripping agent is 45 wt%; during stripping, the stripping temperature of each section is controlled to be 45°C and the phase ratio (O / A) is 10:1.

[0139] (5) Oil-water separation process

[0140] The second organic phase obtained in step (4) is subjected to oil-water separation by a coalescing separator, and the water phase entrained in the second organic phase is removed to obtain a regenerated extractant, which is then returned to step (1) for recycling. During oil-water separation, the separation temperature is controlled to be 40°C, the flow rate of the coalescing separator is controlled to be 200 m³ / h, the working pressure is controlled to be 0.7 MPa, and the working pressure difference is controlled to be 0.15 MPa.

[0141] Example 7

[0142] In this embodiment, a method for extracting and separating rubidium and cesium from a crystallization mother liquor of lithium carbonate is provided, and the steps are as follows:

[0143] (1) Extraction process

[0144] The extractant and the crystallization mother liquor of lithium carbonate are added into a centrifugal extractor, and the alkali metal ions in the crystallization mother liquor of lithium carbonate are subjected to three-stage three-level countercurrent extraction, and the alkali metal ions in the crystallization mother liquor of lithium carbonate are transferred to the extractant to obtain an extraction phase and a raffinate phase.

[0145] The extractant consists of a main extractant and a diluent, the main extractant is t-BAMBP, the diluent is sulfonated kerosene, and the volume ratio of the main extractant to the diluent is 0.7:1; during extraction, the extraction temperature of each section is controlled to be 75°C and the phase ratio (O / A) is 1:1.

[0146] (2) Washing process

[0147] The first detergent and the extract phase obtained in step (1) are added to a centrifugal extractor, and the extract phase is subjected to a three-stage countercurrent washing to obtain the washed extract phase and the first washing residual liquid, and the obtained first washing residual liquid is recycled as the first detergent, wherein the first detergent is deionized water or / and the first washing residual liquid. During washing, the washing temperature is controlled to be 60°C and the phase ratio (O / A) is 7:1.

[0148] (3) First stripping step

[0149] The first stripping agent and the washed extract phase obtained in step (2) are added to a centrifugal extractor for two-stage three-stage countercurrent stripping to obtain a first organic phase and a Cs-enriched phase. + The first stripping solution is evaporated and concentrated to a saturated state, then cooled to 10°C, crystallized for 2 hours, separated, and magnesium cesium sulfate crystals and a first crystallization mother liquor are obtained, and the first crystallization mother liquor is used to prepare a first stripping agent.

[0150] When the reaction just starts running, no first crystallization mother liquor is produced, and the first stripping agent is prepared from magnesium sulfate, sulfuric acid and deionized water. After the reaction runs until the first crystallization mother liquor is produced, the first stripping agent is prepared from magnesium sulfate, sulfuric acid and the first crystallization mother liquor, or the first stripping agent is prepared from magnesium sulfate, sulfuric acid, the first crystallization mother liquor and deionized water, in which the concentration of magnesium sulfate is 40 wt%, and the concentration of sulfuric acid is 8 wt%. During stripping, the stripping temperature of each section is controlled to be 35°C and the phase ratio (O / A) is 5:1.

[0151] (4) Second stripping process

[0152] The second stripping agent and the first organic phase obtained in step (3) are added to a centrifugal extractor for three-stage three-stage countercurrent stripping to obtain a second organic phase and Rb-enriched +A second stripping solution is prepared; aluminum sulfate is added to the second stripping solution and fully dissolved to make the concentration of aluminum sulfate 40 wt%, then cooled to 5 ° C, crystallized for 2 h, separated, and aluminum sulfate rubidium crystals and a second crystallization mother liquor are obtained, and the second crystallization mother liquor is used to prepare a second stripping agent.

[0153] When the reaction just starts running, no second crystallization mother liquor is produced, and the second stripping agent is prepared from sulfuric acid and deionized water. After the reaction runs until the second crystallization mother liquor is produced, the second stripping agent is prepared from sulfuric acid and the second crystallization mother liquor, or the second stripping agent is prepared from sulfuric acid, the second crystallization mother liquor and deionized water, and the concentration of sulfuric acid in the second stripping agent is 50 wt%; during stripping, the stripping temperature of each section is controlled to be 60°C and the phase ratio (O / A) is 6:1.

[0154] (5) Second washing process

[0155] The second detergent and the second organic phase obtained in step (4) are added to a centrifugal extractor, and the second organic phase is subjected to two-stage three-stage countercurrent washing to obtain a regenerated extractant and a second washing residual liquid, and the obtained second washing residual liquid is used to prepare a second detergent. The regenerated extractant is returned to step (1) for recycling.

[0156] When the reaction just starts running, no second washing residual liquid is produced, and the second detergent is prepared from hydrochloric acid and deionized water. After the reaction is run to produce the second washing residual liquid, the second detergent is prepared from hydrochloric acid and the second washing residual liquid, or the second detergent is prepared from hydrochloric acid, the second washing residual liquid and deionized water, and the concentration of hydrochloric acid in the second detergent is 1wt%. During washing, the washing temperature of each section is controlled to be 55°C, and the ratio (O / A) is 3:1.

[0157] Example 8

[0158] In this embodiment, a method for extracting and separating rubidium and cesium from a crystallization mother liquor of lithium carbonate is provided, and the steps are as follows:

[0159] (1) Extraction process

[0160] The extractant and the crystallization mother liquor of lithium carbonate are added into a centrifugal extractor, and the alkali metal ions in the crystallization mother liquor of lithium carbonate are subjected to three-stage three-level countercurrent extraction, and the alkali metal ions in the crystallization mother liquor of lithium carbonate are transferred to the extractant to obtain an extraction phase and a raffinate phase.

[0161] The extractant consists of a main extractant and a diluent, the main extractant is t-BAMBP, the diluent is sulfonated kerosene, and the volume ratio of the main extractant to the diluent is 0.2:1; during extraction, the extraction temperature of each section is controlled to be 75°C and the phase ratio (O / A) is 4:1.

[0162] (2) Oil-water separation process

[0163] The extract phase obtained in step (1) is subjected to oil-water separation by a coalescing separator, and the water phase entrained in the extract phase is removed to obtain an extract phase after the water phase is separated. During the oil-water separation, the separation temperature is controlled to be 40°C, the flow rate of the coalescing separator is controlled to be 500 m³ / h, the working pressure is controlled to be 0.7 MPa, and the working pressure difference is controlled to be 0.15 MPa.

[0164] (3) First stripping step

[0165] The first stripping agent and the extract phase obtained after the aqueous phase is separated in step (2) are added to a centrifugal extractor for five-stage three-stage countercurrent stripping to obtain a first organic phase and a Cs-enriched phase. + The first stripping solution is evaporated and concentrated to a saturated state, then cooled to 10°C, crystallized for 2 hours, separated, and magnesium cesium sulfate crystals and a first crystallization mother liquor are obtained, and the first crystallization mother liquor is used to prepare a first stripping agent.

[0166] When the reaction just starts running, no first crystallization mother liquor is produced, and the first stripping agent is prepared from magnesium sulfate, sulfuric acid and deionized water. After the reaction runs until the first crystallization mother liquor is produced, the first stripping agent is prepared from magnesium sulfate, sulfuric acid and the first crystallization mother liquor, or the first stripping agent is prepared from magnesium sulfate, sulfuric acid, the first crystallization mother liquor and deionized water, in which the concentration of magnesium sulfate and the concentration of sulfuric acid are 45 wt% and 1 wt% respectively. During stripping, the stripping temperature of each section is controlled to be 30°C and the phase ratio (O / A) is 3:1.

[0167] (4) Second stripping process

[0168] The second stripping agent and the first organic phase obtained in step (3) are added to a centrifugal extractor for five-stage three-stage countercurrent stripping to obtain a second organic phase and Rb-enriched + A second stripping solution is prepared; aluminum sulfate is added to the second stripping solution and fully dissolved to make the concentration of aluminum sulfate 40 wt%, then cooled to 5 ° C, crystallized for 2 h, separated, and aluminum sulfate rubidium crystals and a second crystallization mother liquor are obtained, and the second crystallization mother liquor is used to prepare a second stripping agent.

[0169] When the reaction just starts running, no second crystallization mother liquor is produced, and the second stripping agent is prepared from sulfuric acid and deionized water. After the reaction runs until the second crystallization mother liquor is produced, the second stripping agent is prepared from sulfuric acid and the second crystallization mother liquor, or the second stripping agent is prepared from sulfuric acid, the second crystallization mother liquor and deionized water, and the concentration of sulfuric acid in the second stripping agent is 40 wt%; during stripping, the stripping temperature of each section is controlled to be 45°C and the phase ratio (O / A) is 2:1.

[0170] (5) Washing process

[0171] The second detergent and the second organic phase obtained in step (4) are added to a centrifugal extractor, and the second organic phase is subjected to a two-stage countercurrent washing to obtain a regenerated extractant and a second washing raffinate, and the obtained second washing raffinate is used to prepare a second detergent. The regenerated extractant is returned to step (1) for recycling.

[0172] When the reaction just starts running, no second washing residual liquid is produced, and the second washing agent is prepared from nitric acid and deionized water. After the reaction runs until the second washing residual liquid is produced, the second washing agent is prepared from nitric acid and the second washing residual liquid, or the second washing agent is prepared from nitric acid, the second washing residual liquid and deionized water, and the concentration of nitric acid in the second washing agent is 5wt%. During washing, the washing temperature is controlled to be 55°C, and the ratio (O / A) is 3:1.

[0173] Comparative Example 1

[0174] In this comparative example, a method for extracting and separating rubidium and cesium from a crystallization mother liquor of lithium carbonate is provided, and the steps are as follows:

[0175] (1) Extraction process

[0176] The operation of the extraction step is the same as step (1) of Example 1.

[0177] (2) Oil-water separation process

[0178] The operation of the oil-water separation step is the same as step (2) of Example 1.

[0179] (3) First stripping step

[0180] The first stripping agent and the extract phase obtained after separation of the aqueous phase in step (2) are added to a centrifugal extractor for two-stage three-stage countercurrent stripping to obtain a first organic phase and a Cs-enriched phase. + The first stripping solution is evaporated and concentrated to a saturated state, then cooled to 30°C, crystallized for 3 hours, separated, and magnesium cesium sulfate crystals and a first crystallization mother liquor are obtained, and the first crystallization mother liquor is used to prepare a first stripping agent.

[0181] When the reaction just starts running, no first crystallization mother liquor is produced, and the first stripping agent is prepared from magnesium sulfate and deionized water. After the reaction runs until the first crystallization mother liquor is produced, the first stripping agent is prepared from magnesium sulfate and the first crystallization mother liquor, or the first stripping agent is prepared from magnesium sulfate, the first crystallization mother liquor and deionized water, and the concentration of magnesium sulfate in the first stripping agent is 35 wt% of magnesium sulfate; during stripping, the stripping temperature of each section is controlled to be 30°C and the phase ratio (O / A) is 1:1.

[0182] (4) Second stripping process

[0183] The operation of the second stripping step is the same as step (4) of Example 1.

[0184] (5) Washing process

[0185] The washing process is the same as step (5) of Example 1.

[0186] During the continuous operation of Examples 1 to 8 and Comparative Example 1, samples were taken at regular intervals for testing and calculation of the extraction rates of cesium and rubidium, the stripping rates of cesium and rubidium, and the recovery rates of cesium and rubidium of each Example and Comparative Example 1, and the purity of the cesium complex salt crystals and rubidium complex salt crystals obtained in Examples 1 to 8 and Comparative Example 1 was tested. Tables 2 to 4 show the extraction rates, stripping rates, recovery rates, and product purity data after Examples 1 to 8 were continuously operated for 1 day and Comparative Example 1 was continuously operated for 10 h.

[0187] The extraction rate is calculated as follows: the ratio of the mass of cesium or rubidium extracted into the extraction phase to the mass of cesium or rubidium in the crystallization mother liquor of lithium carbonate.

[0188] The stripping rate is calculated as follows: the ratio of the mass of cesium or rubidium in the double salt of cesium or rubidium obtained through stripping to the mass of cesium or rubidium in the extraction phase.

[0189] The recovery rate is calculated as follows: the ratio of the mass of cesium or rubidium in the double salt of cesium or rubidium obtained through the stripping operation to the mass of cesium or rubidium in the crystallization mother liquor of lithium carbonate.

[0190] Table 2 Extraction rate, stripping rate, recovery rate and product purity of metal ions in Example 1 and Comparative Example 1

[0191]

[0192] Table 3 Extraction rate, stripping rate, recovery rate and product purity of metal ions in Examples 2 to 5

[0193]

[0194] Table 4 Extraction rate, stripping rate, recovery rate and product purity of metal ions in Examples 6 to 8

[0195]

[0196] After 10 h of continuous operation, the extraction rate, stripping rate, recovery rate of cesium and rubidium, and the purity of the obtained cesium double salt crystals and rubidium double salt crystals of Comparative Example 1 all showed a significant decrease compared with the initial operation, so the operation was stopped after 10 h of continuous operation of Comparative Example 1. After 1 day of continuous operation, Example 1 still performed well in terms of the extraction rate, stripping rate, recovery rate of cesium and rubidium, and the purity of the obtained cesium double salt crystals and rubidium double salt crystals. As shown in Table 2, after 10 h of continuous operation of Comparative Example 1 and 1 day of continuous operation of Example 1, there were obvious differences in the extraction rate, stripping rate, recovery rate of cesium and rubidium, and the purity of the obtained cesium double salt crystals and rubidium double salt crystals of Example 1 and Comparative Example 1. The main difference between Example 1 and Comparative Example 1 is that the composition of the first stripping agent used in the first stripping process of the two is different, and sulfuric acid is not added to the first stripping agent used in the first stripping process of Comparative Example 1. This shows that in the first stripping step of the method described in the present invention, sulfate and acid are used in combination in an appropriate proportion and concentration level as the first stripping agent, which can effectively improve the extraction rate, stripping rate and recovery rate of cesium and rubidium after long-term continuous operation of the process, and can also improve the purity of the obtained cesium complex salt crystals and rubidium complex salt crystal products. This is mainly because: in the first stripping step of the method described in the present invention, a solution containing high concentrations of sulfate and acid is used as the first stripping agent. In a solution environment containing high concentrations of sulfate, only a small amount of cesium ions is needed to allow cesium ions to precipitate in the form of cesium sulfate complex salt crystals, thereby serving as the outlet of cesium ions in the entire process and improving the stripping effect of cesium ions; at the same time, in the first stripping step, the appropriate concentration of acid in the first stripping agent can strip out the impurity ions in the extracted phase after washing or the extracted phase after separation of the aqueous phase, thereby reducing the content of impurity ions in the first organic phase. After the first organic phase is stripped with the second stripping agent, the second stripping agent is used to strip the first organic phase. The acid in the second stripping agent can further strip the impurity ions in the first organic phase, further reducing the content of impurity ions in the subsequently obtained regenerated extractant, thereby improving the recycling performance of the extractant; since the first stripping step improves the stripping effect on cesium ions, as many cesium ions as possible are stripped out, thereby reducing the difficulty of stripping rubidium ions in the second stripping step, and improving the extraction and separation effect of the process on cesium and rubidium; the reduction in the content of impurity ions in the regenerated extractant can improve the recycling performance of the extractant, and the improvement of the recycling performance of the extractant is conducive to improving the extraction effect of cesium and rubidium in the long-term operation of the entire process.

[0197] As shown in Tables 2 to 4, after one day of continuous operation, the extraction rates of cesium and rubidium, the stripping rates of cesium and rubidium, and the recovery rates of cesium and rubidium in Examples 1 to 8 were all above 98%, and the purity of the cesium double salt crystals and rubidium double salt crystals obtained in Examples 1 to 8 was all above 98%. This shows that the method of the present invention has better long-term operation stability.

[0198] The above embodiments are only some embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art may make non-essential adjustments such as equivalent replacements or changes based on the technical concepts and technical solutions of the present invention. All equivalent replacements and non-essential adjustments should be included in the protection scope of the present invention.

Claims

1. A method for extracting and separating rubidium and cesium from a crystallization mother liquor of lithium carbonate, characterized in that: The following steps are involved: (1) Extraction process An extractant is used to extract alkali metal ions in a crystallization mother liquor of lithium carbonate; the extractant is composed of a main extractant and a diluent, and the volume ratio of the main extractant to the diluent is (0.1-1): 1; during extraction, the extraction temperature is controlled to be 20-85°C and the phase ratio is (1-10): 1; (2) Washing or oil-water separation process The extract phase obtained in step (1) is washed with a first detergent to obtain a washed extract phase and a first washing residual liquid, and the obtained first washing residual liquid is recycled as a first detergent, wherein the first detergent is water and / or the first washing residual liquid; Alternatively, the extract phase obtained in step (1) is subjected to oil-water separation by a separation device, and the water phase entrained in the extract phase is removed to obtain an extract phase after the water phase is separated; (3) First stripping step The first stripping agent is used to strip the washed extract phase obtained in step (2) or the extract phase after separation of the aqueous phase to obtain a first organic phase and a Cs-enriched phase. + first stripping solution; evaporating and concentrating the first stripping solution, cooling and crystallizing, and separating to obtain cesium double salt crystals and a first crystallization mother liquor, and using the first crystallization mother liquor to prepare a first stripping agent; The first stripping agent is prepared from sulfate, acid and water or / and the first crystallization mother liquor. In the first stripping agent, the concentration of sulfate is 20 wt%~50 wt%, and the concentration of acid is 1 wt%~15 wt%. During stripping, the stripping temperature is controlled to be 20~85°C, and the ratio is (1~10):

1. (4) Second stripping process The first organic phase obtained in step (3) is stripped with a second stripping agent to obtain a second organic phase and Rb-enriched + adding sulfate to the second stripping solution until the concentration of sulfate is 20 wt% to 50 wt%, cooling and crystallizing, separating, obtaining rubidium double salt crystals and a second crystallization mother liquor, and using the second crystallization mother liquor to prepare a second stripping agent; The second stripping agent is prepared from acid and water or / and the second crystallization mother liquor, and the acid concentration in the second stripping agent is 10wt%~60wt%; during stripping, the stripping temperature is controlled to be 25~65℃, and the ratio is (1~10): 1; (5) Second washing or oil-water separation process The second organic phase obtained in step (4) is washed with a second washing agent to obtain a regenerated extractant and a second washing residual liquid, and the obtained second washing residual liquid is used to prepare a second washing agent; the second washing agent is prepared from an acid and water or / and the second washing residual liquid, and the concentration of the acid in the second washing agent is 1 wt% to 10 wt%; Alternatively, the second organic phase obtained in step (4) is subjected to oil-water separation by a separation device, and the water phase entrained in the second organic phase is removed to obtain a regenerated extractant; and the regenerated extractant is returned to step (1) for recycling.

2. The method for extracting and separating rubidium and cesium from the crystallization mother liquor of lithium carbonate according to claim 1, characterized in that: The sulfate in step (3) to step (4) is ferric sulfate, ferrous sulfate, manganese sulfate, ammonium sulfate, aluminum sulfate or magnesium sulfate.

3. The method for extracting and separating rubidium and cesium from the crystallization mother liquor of lithium carbonate according to claim 1, characterized in that: The acid in steps (3) to (5) includes at least one of sulfuric acid, hydrochloric acid, nitric acid, oxalic acid, phosphoric acid, acetic acid and citric acid.

4. The method for extracting and separating rubidium and cesium from the crystallization mother liquor of lithium carbonate according to claim 1, characterized in that: The main extractant in step (1) is 4-tert-butyl-2-(α-methylbenzyl)phenol, di(2-ethylhexyl)phosphate, 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester, di(2,4,4-trimethylpentyl)phosphorous acid, dinonylnaphthalenesulfonic acid, cycloalkane acid or tert-carbonic acid.

5. The method for extracting and separating rubidium and cesium from the crystallization mother liquor of lithium carbonate according to claim 4, characterized in that: The diluent in step (1) is at least one of sulfonated kerosene, n-hexane, octane, cyclohexane, decane, nonane, n-heptane, dodecane, solvent oil, xylene, diethylbenzene, carbon tetrachloride, benzene and petroleum ether.

6. The method for extracting and separating rubidium and cesium from the crystallization mother liquor of lithium carbonate according to any one of claims 1 to 5, characterized in that: The extraction method adopted in step (1) is a multi-stage countercurrent extraction, and the stripping method adopted in steps (3) to (4) is a multi-stage countercurrent stripping.

7. The method for extracting and separating rubidium and cesium from the crystallization mother liquor of lithium carbonate according to claim 6, characterized in that: The number of sections of the multi-section and multi-stage countercurrent extraction is 1 to 5 sections, and the number of levels of each section is 1 to 5 levels. The number of sections of the multi-section and multi-stage countercurrent stripping is 1 to 5 sections, and the number of levels of each section is 1 to 5 levels.

8. The method for extracting and separating rubidium and cesium from the crystallization mother liquor of lithium carbonate according to any one of claims 1 to 5, wherein when the first detergent is used to wash the extract phase obtained in step (1) in step (2), the washing temperature is controlled to be 20-85°C and the phase ratio is (1-10): 1; when the second detergent is used to wash the second organic phase obtained in step (4) in step (5), the washing temperature is controlled to be 25-65°C and the phase ratio is (1-10):

1.

9. The method for extracting and separating rubidium and cesium from the crystallization mother liquor of lithium carbonate according to any one of claims 1 to 5, characterized in that: During the washing in step (2) and step (5), the washing method adopted is a multi-stage countercurrent washing.

10. The method for extracting and separating rubidium and cesium from the crystallization mother liquor of lithium carbonate according to claim 9, characterized in that: The number of sections and stages of countercurrent washing is 1 to 3, and the number of stages in each section is 1 to 3.

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