Method for extracting and recovering cesium and rubidium from ore lithium extraction tail liquid by adopting centrifugal extraction method

Abstract

The invention discloses a method for extracting and recovering cesium and rubidium from ore lithium extraction tail liquid by adopting a centrifugal extraction method. The method comprises the steps of preparation of an extraction water phase, preparation of an extraction organic phase, cesium extraction and rubidium extraction, the extraction organic phase is composed of an extraction agent and a diluent, and the extraction agent is 4-tert-butyl-2-(alpha-methylbenzyl) phenol. Based on centrifugal extractor equipment, the invention provides an extraction-washing-reverse extraction full-flow process method for efficiently extracting and recovering rubidium and cesium salts from the ore lithium extraction tail liquid, and cesium and rubidium can be efficiently recovered from multi-component complex feed liquid of the ore lithium extraction tail liquid containing rubidium and cesium through the multi-stage extraction, washing and reverse extraction process. According to the method, high-purity rubidium salt and cesium salt products are obtained, the yield of the rubidium salt and cesium salt is high, the technological process has the advantages of being high in operability, good in continuity, easy in technological amplification, low in production cost, high in yield, high in product purity and the like, and a technological path is provided for actual industrial production.

Description

Technical Field

[0001] This invention relates to a process for recovering cesium and rubidium salts, specifically a process for selectively recovering and extracting rubidium and cesium from lithium extraction tailings (waste liquid) of ores containing cesium, rubidium, sodium, potassium, and lithium using centrifugal extraction. It belongs to the field of resource recovery and recycling and separation and purification technology. Background Technology

[0002] Rubidium and cesium are highly reactive metallic elements, and among the lightest and softest metals, possessing excellent electrical and thermal conductivity. Rubidium and cesium have very low ionization potentials and electron work functions, exhibiting a significant photoelectric effect; their surfaces readily release electrons when exposed to light, forming a photocurrent. Due to their unique physical and chemical properties, rubidium, cesium, and their compounds are widely used in the manufacture of highly precise cesium atomic clocks, specialized optical devices, magnetohydrodynamic generators, radiation medicine, the chemical industry, and oil extraction, making them important resources.

[0003] Elemental cesium does not exist in nature. It primarily exists as oxides or double salts in pegmatite minerals, and some cesium also exists as halides in brine. Rubidium is widely distributed in nature, found in mineral water, plant ash, tea, coffee, beets, and certain citrus fruits. Rubidium is classified as a "rare element" because of its widespread distribution in the Earth's crust, but it rarely forms standalone minerals. The separation, extraction, and smelting of rubidium and cesium are extremely difficult, making them very expensive.

[0004] Whether it's pegmatite-type rubidium and cesium ores or liquid resources such as salt lakes, underground brines, and oilfield water, the separation and extraction of rubidium and cesium is challenging due to their very similar physicochemical properties to other associated alkali metals. In recent years, the increasing market demand for rubidium and cesium worldwide has made their separation and extraction technology a research hotspot. Rubidium and cesium-containing minerals mainly include solid minerals such as pegmatites and liquid minerals such as brines. After leaching, solid minerals, like liquid minerals, require extraction of rubidium and cesium from the solution. Lithium extraction tailings from ores contain high-grade rubidium and cesium resources, which are usually associated with alkali metals such as sodium, potassium, and lithium, making separation and extraction difficult. The most studied methods for separating and extracting cesium include precipitation, adsorption, and solvent extraction.

[0005] First, precipitation method

[0006] Commonly used precipitation methods for separating and extracting bulky anions of rubidium and cesium include heteropolyacids, complex salts, polyhalides, alums, and certain organic reagents. Among the more studied precipitants are silylamic (tungsten) acid, chloroplatinic acid, tin tetrachloride, potassium bismuth iodophosphate, sodium tetraphenylborate, and ferrocyanides. These precipitants offer high cesium recovery rates; however, their high cost, complex precipitation recovery processes, and poor stability of the resulting precipitates are all limiting factors for their practical application. Precipitation methods can be used for the analysis and testing of cesium salts, or for the further separation and purification of crude products, but they are difficult to use for the economical and efficient separation of cesium salts from complex multi-component raw material systems.

[0007] Second, adsorption method

[0008] Adsorption, also known as ion exchange, is suitable for enriching and separating rubidium and cesium from solutions with low rubidium and cesium content. It has been extensively studied and rapidly developed in recent years, and is one of the important methods for separating and extracting rubidium and cesium resources. Based on the type of adsorbent, it can be divided into several categories: natural mineral adsorbents, inorganic salt adsorbents, organic resin adsorbents, organic-inorganic composite adsorbents, and biomass adsorbents.

[0009] Natural inorganic minerals such as zeolite, kaolin, and diatomite belong to the aluminosilicate mineral class, and their crystal structure contains Si. 4+ Often by AI 3+ When excess charge occurs due to substitution, alkali metals such as Li, Na, K, Rb, and Cs fill the crystal lattice to compensate for the excess negative charge in order to achieve electroneutrality. Therefore, these alkali metal ions can move freely within the crystal lattice and exchange with some other ions. This structural characteristic gives them excellent adsorption properties. Based on the different natural mineral raw materials, rubidium-cesium adsorbents can be further classified into natural clinoptilolite, natural montmorillonite, natural diatomaceous earth, and other types of natural minerals.

[0010] A number of special inorganic salt compounds have been widely studied as adsorption and separation raw materials for alkali metal ions. These compounds are primarily composed of polyvalent metal acidic salts and possess excellent stability, heat resistance, radiation resistance, selectivity, and mechanical properties. Their advantages, such as easy control of the ion exchange process, high efficiency, continuous column operation, simple equipment, and relatively mature technology, have made them a focus of research. In recent years, research on cesium adsorbents has gradually shifted towards the synthesis of composite adsorbents based on these substances. Based on the type of inorganic salt, cesium adsorbents are classified into several major categories: heteropolyacids, phosphates, metal ferrocyanides, titanates, and other types.

[0011] While adsorption technology excels in separating low-content components in solutions, its application is constrained by the composition of the feed system and the physicochemical properties of the adsorbent itself. Most research remains confined to the laboratory stage, and several bottlenecks persist. Therefore, there is an urgent need to design and synthesize structurally stable inorganic materials as carriers for adsorbents. Preparing particulate organic-inorganic composite cesium adsorbents will be an effective method for separating and extracting rubidium and cesium salts.

[0012] Third, solvent extraction method

[0013] Solvent extraction is a classic separation technique that has long been used in analytical chemistry. With the rapid development of industries such as nuclear science, petrochemicals, and non-ferrous metals, this traditional separation science and technology has advanced rapidly. Solvent extraction plays a crucial role in the separation and production of important strategic elements in my country, such as the separation of single high-purity rare earth elements from rare earth mines in Inner Mongolia and Jiangxi, the extraction of nickel and cobalt and the separation of precious metals from the Jinchuan nickel-cobalt mine, and the separation and extraction of copper from copper ore heap leaching solutions or tailings.

[0014] Solvent extraction technology utilizes the difference in binding ability of organic compounds (extractants) to target components and coexisting impurity components to achieve effective separation of the target component. A classic solvent extraction process generally includes four steps: extraction, washing, back-extraction, and regeneration. Taking cesium separation and extraction as an example, the extraction stage can achieve the separation of Cs from multiple components. + With coexisting Rb + Na + K + Li + Preliminary separation of coexisting impurity ions, followed by thorough elution of extracted impurity ions (Rb) in the washing section. + Na + K + Li + (etc.), for the extracted Cs + Further purification is performed, and Cs is removed in the back-extraction section. + By stripping from the organic phase and controlling appropriate operating conditions, high-concentration, high-purity Cs-rich products can be obtained. + The solution is used to prepare cesium salt products. The regeneration section restores the extractant's extraction capacity for recycling. The complete extraction process simultaneously achieves the separation, purification, concentration of rubidium and cesium, and the recycling of the extractant. Compared to precipitation and adsorption methods, solvent extraction technology with a well-designed process configuration offers significant advantages in separating and extracting cesium from cesium-containing solutions, with a simplified process flow.

[0015] Solvent extraction is an important method for separating and extracting rubidium and cesium. Research on this method began in the United States in the 1960s, and related research has continued uninterrupted for the past 60 years. It is also the most promising method for large-scale industrial application. The most studied rubidium and cesium extraction systems mainly include substituted phenols and crown ethers. Dipicrin extraction systems were extensively studied in the past and were considered useful for the reprocessing of radioactive nuclear fuel. 137 However, due to its high toxicity and the high toxicity and risk factor of the solvent nitrobenzene, it has been rarely studied in the Cs process in recent decades.

[0016] Substituted phenolic compounds are the most studied extraction systems for the extraction and separation of rubidium and cesium. When using substituted phenolic extractants, H+ is generated through the dissociation of hydroxyl groups under alkaline conditions. + and Rb in the aqueous phase + Cs + Extraction is achieved through cation exchange; the extraction mechanism is a cation exchange reaction, and the specific reaction formula is as follows:

[0017] M + +mHOR→MOR+mH +

[0018] Where M+ represents Rb + Cs + Alkali metal ions, ROH represents substituted phenolic extractant, and ROM represents extractant.

[0019] There are existing studies and some published patents, such as CN 107217156 A, CN 106929693 A, CN115124054 A, CN 115180640 A, CN 103787375A, etc. However, the existing separation technology has a long process, low yield, low product purity and high cost, making it difficult to realize industrial application. Summary of the Invention

[0020] The main objective of this invention is to provide a method for extracting and recovering cesium and rubidium from lithium extraction tailings from ore using centrifugal extraction, thereby overcoming the shortcomings of the prior art.

[0021] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0022] This invention provides a method for extracting and recovering cesium and rubidium from lithium extraction tailings from ore using centrifugal extraction, comprising:

[0023] The tailings of lithium extraction from ore containing at least rubidium, cesium, sodium, potassium, and lithium are adjusted with an alkaline substance, filtered, and the filtrate is used as the aqueous raw material for cesium extraction. The concentration of rubidium in the tailings of lithium extraction from ore is 0.05 g / L to 20 g / L, the concentration of cesium is 0.05 g / L to 10 g / L, the concentration of sodium is 0 to 100 g / L, the concentration of potassium is 0 to 100 g / L, and the concentration of lithium is 0 to 40 g / L.

[0024] A first extractable organic phase comprising an extractant and a diluent is provided, and the first extractable organic phase and the aqueous cesium-extracting feedstock are co-introduced into a centrifugal extractor for multi-stage countercurrent cascade extraction to obtain a cesium-loaded organic phase and a cesium-extracting residue; wherein, the flow ratio of the first extractable organic phase to the aqueous cesium-extracting feedstock is 1:5 to 5:1, the number of extraction stages is 2 to 8, the residence time of the first extractable organic phase and the aqueous cesium-extracting feedstock in each stage of the centrifugal extractor is 0.1 to 5 min, and the temperature of the two phases during the extraction process is 20 to 60°C; the extractant includes 4-tert-butyl-2-(α-methylbenzyl)phenol;

[0025] The cesium-loaded organic phase was washed with a first detergent in a multi-stage centrifugal extractor to obtain a pure cesium-loaded organic phase.

[0026] The purified cesium-loaded organic phase is fed into a multi-stage centrifugal extractor and cesium is back-extracted with a back-extraction agent to obtain a cesium-rich solution. The solution is then evaporated, concentrated, and crystallized to obtain cesium salt.

[0027] The cesium extraction residue was adjusted with an alkaline substance, filtered, and the filtrate was used as the aqueous phase raw material for rubidium extraction.

[0028] A second extractable organic phase comprising an extractant and a diluent is provided, and the second extractable organic phase and the aqueous extractant of rubidium are co-feeded into a centrifugal extractor for multi-stage countercurrent cascade extraction to obtain a rubidium-loaded organic phase and rubidium-extracted residue; wherein the flow ratio of the second extractable organic phase to the aqueous extractant of rubidium is 1:5 to 5:1, the number of extraction stages is 2 to 8, the residence time of the second extractable organic phase and the aqueous extractant of rubidium in each stage of the centrifugal extractor is 0.1 to 5 min, and the temperature of the two phases during the extraction process is 20 to 60 °C; the extractant includes 4-tert-butyl-2-(α-methylbenzyl)phenol;

[0029] The supported rubidium organic phase was washed with a second detergent in a multi-stage centrifugal extractor to obtain a pure supported rubidium organic phase.

[0030] The purified rubidium-loaded organic phase is fed into a multi-stage centrifugal extractor and back-extracted with a back-extracting agent to obtain a rubidium-enriched solution. The solution is then evaporated, concentrated, and crystallized to obtain rubidium salt.

[0031] In some embodiments, the concentration of the extractant in the diluent in the first extracting organic phase is 0.1–2.0 mol / L.

[0032] In some embodiments, the concentration of the extractant in the diluent in the second extracting organic phase is 0.2–2.0 mol / L.

[0033] In some embodiments, the method includes: purifying the cesium-loaded organic phase by washing with a first detergent in a multi-stage centrifugal extractor, the first detergent comprising any one of deionized water, cesium chloride solution, cesium sulfate solution, cesium nitrate solution, cesium hydroxide solution, and acid solution.

[0034] In some embodiments, the method includes: washing and purifying the rubidium-loaded organic phase with a second detergent in a multi-stage centrifugal extractor, the second detergent comprising any one of deionized water, rubidium chloride solution, rubidium sulfate solution, rubidium nitrate solution, rubidium hydroxide solution, and acid solution.

[0035] In some embodiments, the stripping agent includes any one of acetic acid, nitric acid, hydrochloric acid, carbonic acid, and sulfuric acid, with an acid concentration of 0.01 to 4 mol / L.

[0036] Compared with traditional simple extraction systems, this application has at least the following technical advantages:

[0037] This invention, based on a centrifugal extractor, proposes a complete "extraction-washing-back-extraction" process for the efficient extraction and recovery of rubidium and cesium salts from lithium extraction tailings from ore. Through multi-stage extraction, washing, and back-extraction processes, cesium and rubidium can be efficiently recovered from the complex multi-component feed liquid of lithium extraction tailings containing rubidium and cesium, yielding high-purity rubidium and cesium salt products. This process has advantages such as strong operability, good continuity, easy process scale-up, low production cost, high yield, and high product purity, providing a process path for actual industrial production. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a flowchart of a typical embodiment of the present invention, which describes a process for extracting and recovering cesium and rubidium salts from lithium extraction tailings from ore using centrifugal extraction. Detailed Implementation

[0040] In view of the problems existing in the prior art, the inventors of this case, after long-term research, proposed the technical concept of this invention, which mainly proposes a complete process flow for the efficient extraction and recovery of cesium and rubidium salts from lithium extraction tailings from ore using a centrifugal extractor. This process adopts a different approach from the traditional simple extraction system. Through multi-stage extraction, washing, and back-extraction processes, it can efficiently recover cesium from the complex multi-component feed liquid of lithium extraction tailings from ore containing rubidium and cesium. Furthermore, it provides a complete process flow for the recovery of cesium and rubidium salts based on centrifugal extractors, namely "extraction-washing-back-extraction", providing a process path for actual industrial production.

[0041] The following will provide a further explanation of the technical solution, its implementation process, and its principles.

[0042] As one aspect of the technical solution of the present invention, it relates to a method for extracting and recovering cesium and rubidium from lithium extraction tailings of ore using centrifugal extraction, which includes the preparation of an aqueous phase, the preparation of an organic phase, the extraction process of cesium, and the extraction process of rubidium.

[0043] Please see Figure 1 The diagram illustrates a process for extracting and recovering cesium and rubidium salts from lithium extraction tailings from ore using a centrifugal extractor. The process includes a cesium extraction step and a rubidium extraction step, specifically comprising the following steps:

[0044] Extraction aqueous phase feedstock: Lithium tailings from ore extraction containing rubidium, cesium, sodium, potassium and lithium are used as the extraction aqueous phase feedstock, wherein the concentration of rubidium is 0.05 g / L to 20 g / L, the concentration of cesium is 0.05 g / L to 10 g / L, the concentration of sodium is 0 to 100 g / L, the concentration of potassium is 0 to 100 g / L and the concentration of lithium is 0 to 40 g / L.

[0045] Furthermore, in addition to the five elements mentioned above, the lithium extraction tailings from the ore may also contain any one or more combinations of calcium ions, magnesium ions, iron ions, aluminum ions, chloride ions, sulfate ions, nitrate ions, and carbonate ions, but are not limited to these.

[0046] Extraction organic phase: The extraction organic phase consists of an extractant and a diluent. The extractant is 4-tert-butyl-2-(α-methylbenzyl)phenol (t-BAMBP), and the diluent is at least one of sulfonated kerosene, cyclohexane, cyclohexanone, benzene, toluene, xylene, and trimethylbenzene.

[0047] I. Cesium Extraction Process:

[0048] The entire cesium extraction process is carried out in multiple centrifugal extractors, including extraction and separation, washing and purification, and back-extraction enrichment stages:

[0049] Alkalinity Adjustment: Adjust the alkali concentration of the lithium extraction tailings solution using at least one alkaline substance selected from sodium hydroxide, potassium hydroxide, lithium hydroxide, etc., to improve the alkali concentration of the cesium extraction feed solution (OH-). - The concentration was adjusted to 0.01–1 mol / L, and the precipitated salt was removed by filtration. The filtrate was used as the aqueous phase raw material for cesium extraction.

[0050] Cesium extraction section: t-BAMBP solvent in a diluent is used as the organic phase raw material for cesium extraction. The concentration of t-BAMBP in the diluent is 0.1-2.0 mol / L, which is the first extraction organic phase. The alkali-adjusted feed solution is used as the extraction aqueous phase. The first extraction organic phase and the extraction aqueous phase (i.e., the aqueous raw material for cesium extraction) are fed into a centrifugal extractor at a flow ratio of Qo / Qa = 1:5-5:1 for multi-stage countercurrent cascade extraction. The number of extraction stages is 2-8. The residence time of the organic phase (i.e., the first extraction organic phase) and the aqueous feed solution (i.e., the aqueous raw material for cesium extraction) in each centrifugal extractor stage is 0.1-5 minutes. During the extraction process, the temperature of the two phases is maintained at 20-60℃. After the cesium extraction stage, a cesium-loaded organic phase and the residue after cesium extraction (i.e., cesium extraction residue) are obtained. The cesium-loaded organic phase is used in the subsequent washing stage, and the residue after cesium extraction is used as the feed solution for subsequent rubidium extraction.

[0051] Furthermore, the resulting cesium-loaded organic phase is mainly composed of cesium, but contains small amounts of impurities such as rubidium, potassium, and sodium, which must be washed and purified.

[0052] Cesium-loaded organic phase washing section: The cesium-loaded organic phase obtained from the cesium extraction section is washed with the first washing agent (i.e., cesium-loaded organic phase) in a multi-stage centrifugal extractor. Figure 1 The first washing agent ("detergent one") is used for washing and purification to remove impurities such as rubidium, potassium, and sodium from the organic phase as much as possible. The first washing agent can be any one of deionized water, cesium chloride solution, cesium sulfate solution, cesium nitrate solution, cesium hydroxide solution, or an acid solution. When the first washing agent is a cesium chloride solution, cesium sulfate solution, cesium nitrate solution, or cesium hydroxide solution, the concentration is 0.001–1 mol / L. When the first washing agent is an acid solution, the acid can be any one of acetic acid, nitric acid, hydrochloric acid, sulfuric acid, or carbonic acid, and the acid concentration is 0.001–1 mol / L. The number of washing stages is 2–15, the washing flow ratio Qo / Qa = 50:1–1:1, and the residence time of the first extraction organic phase and aqueous phase raw material (i.e., the first washing agent) in each stage centrifugal extractor is 0.1–5 minutes. During the washing process, the temperature of both phases is maintained at 20–60°C. The washing residue is returned to the extraction section and mixed with the raw material liquid for further extraction.

[0053] After the cesium-loaded organic phase washing section, a pure cesium-loaded organic phase and a first washing residue are obtained. The pure cesium-loaded organic phase is used as raw material for the subsequent cesium back-extraction section. The washing liquid after washing cesium mainly contains impurities such as rubidium and potassium, as well as a small amount of cesium lost in the washing section. If the washing residue is discharged, rubidium and cesium will be lost. In this invention, the first washing residue is combined with the extraction liquid and returned to the extraction section to continue the extraction of cesium, so as to minimize rubidium and cesium loss and improve the yield.

[0054] Washed cesium-supported organic phase back-extraction: The purified cesium-supported organic phase is back-extracted using an extraction solvent (i.e.,...) on a multi-stage centrifugal extractor. Figure 1 Cesium is enriched by back-extraction agent 1. Back-extraction agent 1 can be any one of acetic acid, nitric acid, hydrochloric acid, carbonic acid, and sulfuric acid, with an acid concentration of 0.01–4 mol / L. The cesium back-extraction process consists of 2–6 stages, with a washing flow ratio Qo / Qa = 50:1–1:1. The residence time of the organic phase (i.e., the pure cesium-loaded organic phase) and the aqueous phase (i.e., the back-extraction agent) in each centrifugal extractor stage is 0.1–5 minutes. During the back-extraction process, the temperature of both phases is maintained at 20–60°C. After the cesium back-extraction stage, a pure cesium-enriched solution and a blank organic phase are obtained. The cesium-enriched solution is then subjected to evaporation, concentration, and crystallization processes to obtain products such as cesium acetate, cesium nitrate, cesium chloride, cesium carbonate, and cesium sulfate. The blank organic phase after cesium back-extraction is recycled for cesium extraction.

[0055] In the cesium extraction process, the extraction, washing, and cesium back-extraction stages all employ countercurrent cascade operation of multiple centrifugal extractors. This extraction-washing-back-extraction process is repeated continuously, constituting a complete process for extracting and recovering cesium from lithium extraction tailings.

[0056] The residue from cesium extraction is used as the feed solution for rubidium extraction.

[0057] In the cesium extraction section, the first extraction organic phase is pumped in through the light phase inlet of the first centrifugal extractor, and the extraction aqueous phase (i.e., the aqueous raw material for cesium extraction) is pumped in through the heavy phase inlet of the Nth centrifugal extractor in the extraction section, realizing multi-stage countercurrent cascade extraction of cesium. The loaded cesium organic phase is obtained at the light phase outlet of the Nth centrifugal extractor, and the cesium extraction residue is obtained at the heavy phase outlet of the first centrifugal extractor.

[0058] In the washing section of the cesium-loaded organic phase, the cesium-loaded organic phase is pumped to the light phase inlet of the first centrifugal extractor in the washing section, or flows by gravity from the light phase outlet of the Nth centrifugal extractor in the extraction section into the light phase inlet of the first centrifugal extractor in the washing section. Detergent 1 is pumped in from the heavy phase inlet of the Mth centrifugal extractor in the washing section to achieve multi-stage countercurrent cascade washing. The washed and purified cesium-loaded organic phase is obtained at the light phase outlet of the Mth centrifugal extractor in the washing section, and the washing residue 1 is obtained at the heavy phase outlet of the first centrifugal extractor in the washing section. The washing residue 1 is pumped by gravity or pump to the Nth centrifugal extractor in the extraction section to mix with the cesium extraction feed solution and continue to extract cesium.

[0059] In the cesium back-extraction section with a cesium-loaded organic phase, the pure cesium-loaded organic phase is pumped to the light phase inlet of the first centrifugal extractor in the back-extraction section, or it flows by gravity from the light phase outlet of the Mth stage centrifugal extractor in the washing section into the light phase inlet of the first centrifugal extractor in the back-extraction section. The back-extraction agent is pumped in from the heavy phase inlet of the Fth centrifugal extractor in the back-extraction section, realizing multi-stage countercurrent cascade back-extraction. The back-extracted blank organic phase is obtained at the light phase outlet of the Fth centrifugal extractor in the back-extraction section, and the cesium back-extraction enrichment is obtained at the heavy phase outlet of the first centrifugal extractor in the back-extraction section.

[0060] II. Rubidium Extraction Process:

[0061] The rubidium extraction process is carried out in multiple centrifugal extractors, including extraction and separation, washing and purification, and back-extraction enrichment stages:

[0062] Adjusting the alkalinity: Use at least one alkaline substance selected from sodium hydroxide, potassium hydroxide, lithium hydroxide, etc., to adjust the alkalinity (OH-) of the cesium extraction residue. - The concentration was adjusted to 0.1–2.0 mol / L, and the precipitated salt was removed by filtration. The filtrate was used as the aqueous phase raw material for rubidium extraction.

[0063] Rubidium Extraction Section: t-BAMBP solvent in a diluent is used as the organic phase feedstock for rubidium extraction. The concentration of t-BAMBP in the diluent is 0.2–2.0 mol / L, which is the second extraction organic phase. The alkali-adjusted feed solution is used as the extraction aqueous phase. The second extraction organic phase and the extraction aqueous phase (i.e., the aqueous feedstock for rubidium extraction) are fed into a centrifugal extractor at a flow ratio Qo / Qa = 1:5–5:1 for multi-stage countercurrent cascade extraction. The number of extraction stages is 2–8. The residence time of the organic phase (i.e., the second extraction organic phase) and the aqueous feed solution (i.e., the aqueous feedstock for rubidium extraction) in each centrifugal extractor stage is 0.1–5 minutes. During the extraction process, the temperature of both phases is maintained at 20–60℃. After the rubidium extraction section, the rubidium-loaded organic phase and the residual liquid after rubidium extraction are obtained (i.e., the rubidium-loaded organic phase and the residual liquid after rubidium extraction). Figure 1 The rubidium extraction residue is loaded with a rubidium organic phase for subsequent washing processes, and the residue after rubidium extraction is recycled for leaching or for further lithium recovery.

[0064] Furthermore, the resulting rubidium-loaded organic phase is mainly composed of rubidium and contains small amounts of impurities such as potassium and sodium, which must be washed and purified.

[0065] Rubidium-loaded organic phase washing section: The rubidium-loaded organic phase obtained from the rubidium extraction section is washed with a second washing agent (i.e., rubidium-loaded organic phase) in a single-stage or multi-stage centrifugal extractor. Figure 1 The organic phase is washed and purified using "Detergent II" to remove impurities such as rubidium, potassium, and sodium as much as possible. The second detergent can be any one of deionized water, rubidium chloride solution, rubidium sulfate solution, rubidium nitrate solution, rubidium hydroxide solution, or an acid solution. When the second detergent is rubidium chloride solution, rubidium sulfate solution, rubidium nitrate solution, or rubidium hydroxide solution, the concentration is 0.001–1 mol / L; when the second detergent is an acid solution, the acid can be any one of acetic acid, nitric acid, hydrochloric acid, sulfuric acid, or carbonic acid, and the acid concentration is 0.001–2 mol / L. The washing process consists of 2–15 stages, with a washing flow ratio Qo / Qa = 50:1–1:1. The residence time of the rubidium-loaded organic phase and the aqueous phase (i.e., the second detergent) in each centrifugal extractor stage is 0.1–5 minutes, and the temperature of both phases is maintained at 20–60°C during the washing process. The washing residue is returned to the extraction section and mixed with the feed liquid for further extraction.

[0066] After the rubidium-loaded organic phase washing section, a pure rubidium-loaded organic phase and a second washing residue are obtained. The pure rubidium-loaded organic phase is used as raw material for the subsequent rubidium back-extraction section. The washing liquid after washing rubidium mainly contains impurities such as rubidium, potassium, and sodium, as well as a small amount of rubidium lost in the washing section. If the second washing residue is discharged, rubidium loss will occur. In order to minimize rubidium loss and improve yield, the second washing residue is combined with the extraction feed liquid and returned to the extraction section to continue rubidium extraction.

[0067] Washed rubidium-supported organic phase back-extraction: The purified rubidium-supported organic phase is back-extracted using an extraction agent (i.e.,...) on a multi-stage centrifugal extractor. Figure 1 Rubidium is enriched by back-extraction agent 2. Back-extraction agent 2 can be any one of acetic acid, nitric acid, hydrochloric acid, carbonic acid, and sulfuric acid, with an acid concentration of 0.01–4 mol / L. The rubidium back-extraction process consists of 2–6 stages, with a washing flow ratio Qo / Qa = 50:1–1:1. The residence time of the organic phase (i.e., the pure rubidium-loaded organic phase) and the aqueous phase (i.e., the back-extraction agent) in each centrifugal extractor stage is 0.1–5 minutes. During the back-extraction process, the temperature of both phases is maintained at 20–60°C. After the rubidium back-extraction stage, a pure rubidium-enriched solution and a blank organic phase are obtained. The pure rubidium-enriched solution is then subjected to evaporation, concentration, and crystallization processes to obtain products such as rubidium acetate, rubidium nitrate, rubidium chloride, rubidium carbonate, and rubidium sulfate. The blank organic phase after rubidium back-extraction is recycled for further rubidium extraction.

[0068] In the rubidium extraction process, the extraction, washing, and back-extraction sections all employ countercurrent cascade operation of multiple centrifugal extractors.

[0069] The above-described extraction-washing-back-extraction process is repeated continuously, constituting a complete process for extracting and recovering rubidium from lithium extraction tail liquid.

[0070] In summary, the multi-stage extraction, multi-stage washing, and multi-stage back-extraction processes in the rubidium-cesium extraction and separation process are all implemented in a centrifugal extractor, and the multi-stage process is a multi-stage countercurrent operation.

[0071] In the rubidium extraction section, the second extraction organic phase is pumped in through the light phase inlet of the first centrifugal extractor, and the extraction aqueous phase (i.e., the aqueous raw material for rubidium extraction) is pumped in through the heavy phase inlet of the Nth centrifugal extractor in the extraction section, thereby realizing multi-stage countercurrent cascade extraction of cesium. The loaded rubidium organic phase is obtained at the light phase outlet of the Nth centrifugal extractor, and the rubidium extraction residue is obtained at the heavy phase outlet of the first centrifugal extractor.

[0072] In the washing section of the rubidium-loaded organic phase, the rubidium-loaded organic phase is pumped to the light phase inlet of the first centrifugal extractor in the washing section, or flows by gravity from the light phase outlet of the Nth centrifugal extractor in the extraction section into the light phase inlet of the first centrifugal extractor in the washing section. Detergent II is pumped in from the heavy phase inlet of the Mth centrifugal extractor in the washing section, realizing multi-stage countercurrent cascade washing. The washed and purified rubidium-loaded organic phase is obtained at the light phase outlet of the Mth centrifugal extractor in the washing section, and the washing residue II is obtained at the heavy phase outlet of the first centrifugal extractor in the washing section. The washing residue II is pumped by gravity or pump to the Nth centrifugal extractor in the extraction section to mix with the rubidium extraction feed solution and continue to extract rubidium.

[0073] In the rubidium-loaded organic phase back-extraction section, the rubidium-loaded organic phase is pumped to the light phase inlet of the first centrifugal extractor in the back-extraction section, or flows by gravity from the light phase outlet of the Mth stage centrifugal extractor in the washing section into the light phase inlet of the first centrifugal extractor in the back-extraction section. The second back-extraction agent is pumped in from the heavy phase inlet of the Fth centrifugal extractor in the back-extraction section, realizing multi-stage countercurrent cascade back-extraction. The back-extracted blank organic phase is obtained at the light phase outlet of the Fth centrifugal extractor in the back-extraction section, and the rubidium back-extraction enrichment is obtained at the heavy phase outlet of the first centrifugal extractor in the back-extraction section.

[0074] In summary, by employing the above technical solutions, this invention achieves high-purity rubidium and cesium salt products through a multi-stage extraction, washing, and back-extraction process, resulting in high yields of both rubidium and cesium salts. A complete process flow for extracting and recovering cesium and rubidium salts from lithium extraction tailings from ore using a centrifugal extractor is proposed, offering advantages such as strong operability, good continuity, easy process scale-up, low production cost, high yield, and high product purity.

[0075] The technical solutions of the present invention will be described in detail below with reference to specific embodiments, so that those skilled in the art can better understand and implement the technical solutions of the present invention. The specific functional details disclosed herein should not be construed as limiting, but are merely intended to form the basis of the claims and to teach those skilled in the art to employ the representative basis of the invention in different ways in any suitable detailed embodiment.

[0076] Example 1:

[0077] (a) Cesium extraction process:

[0078] (1) Aqueous raw materials: Potassium hydroxide was dissolved in the lithium extraction tailings with Cs, Rb, Na, K, and Li concentrations of 0.37, 1.12, 73.8, 14.7, and 7.8 g / L, respectively, to make OH... - The concentration was 0.8 mol / L. The precipitated salt was removed by filtration, and the filtrate was used as the aqueous feed solution for cesium extraction.

[0079] (2) Organic phase raw materials: t-BAMBP was dissolved in sulfonated kerosene as the organic phase for cesium extraction, and the concentration of t-BAMBP was 2.0 mol / L.

[0080] (3) Extraction section: The above-mentioned organic phase is pumped into the light phase inlet of the first centrifuge in the extraction section, and the aqueous phase is pumped into the heavy phase inlet of the second centrifugal extractor. The flow ratio of organic phase to aqueous phase is controlled to be 1 / 5, so that the organic phase and aqueous phase are subjected to two-stage countercurrent cascade extraction of cesium in the two centrifuges, and the cesium-loaded organic phase and the cesium extraction residue are obtained respectively. The residence time of organic phase and aqueous phase in each centrifugal extractor is 0.63 min, and the temperature of the two phases is 20℃ during the extraction process.

[0081] (4) Washing section: Deionized water is used as the detergent. The cesium-loaded organic phase is washed in 15 stages of countercurrent washing on a 15-stage centrifugal extractor. The organic phase flows by gravity from the light phase outlet of the second stage centrifugal extractor in the extraction section into the light phase inlet of the first stage centrifugal extractor in the washing section. The detergent (deionized water) is pumped into the heavy phase inlet of the 15th stage of the washing section. The flow ratio of organic phase to detergent is controlled at 4 / 1. The washing residue and the purified cesium-loaded organic phase are obtained respectively. The collected washing residue is pumped to the heavy phase inlet of the second stage centrifugal extractor in the extraction section for further extraction. The residence time of organic phase and detergent in each stage centrifugal extractor is 3.04 min. The temperature of the two phases during the washing process is 20℃.

[0082] (5) Back-extraction section: Using 0.15 mol / L H2SO4 solution as the back-extraction agent, a 6-stage countercurrent back-extraction of the cesium-loaded organic phase is carried out on a 6-stage centrifugal extractor. The organic phase flows by gravity from the light phase outlet of the 15th stage centrifugal extractor in the washing section into the light phase inlet of the 1st stage centrifugal extractor in the back-extraction section. The back-extraction agent (0.15 mol / L H2SO4 solution) is pumped into the heavy phase inlet of the 6th stage of the back-extraction section. The flow ratio of organic phase to back-extraction agent is controlled at 20 / 1. Cesium sulfate-enriched back-extraction solution and blank organic phase are obtained respectively. The cesium sulfate-enriched back-extraction solution is used to prepare cesium sulfate products. The collected blank organic phase is pumped to the light phase inlet of the 1st centrifuge in the extraction section for the next extraction cycle. The residence time of the organic phase and back-extraction solution in each stage centrifugal extractor is 3.62 min. The temperature of the two phases during the back-extraction process is 20℃.

[0083] (6) Extraction and recovery of cesium: The above extraction-washing-back-extraction process is repeated to form a complete process for extracting and recovering cesium from lithium extraction tail liquid.

[0084] Testing revealed that the cesium extraction rate in the extraction section reached 97.87%, the washing efficiency of rubidium, potassium, sodium, and lithium in the washing section all exceeded 99.5%, the average cesium loss rate in the washing section was 17.82%, the cesium back-extraction rate in the back-extraction section exceeded 99%, and the purity of the obtained cesium sulfate enriched back-extraction solution was 99.86%. After the washing solution reflux extraction process, the total cesium yield was over 97%.

[0085] (II) Rubidium Extraction Process:

[0086] (1) Aqueous phase feedstock: Dissolve potassium hydroxide in the cesium extraction residue to make OH... - The concentration was 2.0 mol / L. The precipitated salt was removed by filtration, and the filtrate was used as the aqueous feed solution for rubidium extraction.

[0087] (2) Organic phase raw materials: t-BAMBP was dissolved in tricresylene as the rubidium organic phase for extraction, and the concentration of t-BAMBP was 0.4 mol / L.

[0088] (3) Extraction section: The above-mentioned organic phase is pumped into the light phase inlet of the first centrifuge in the extraction section, and the aqueous phase is pumped into the heavy phase inlet of the fifth centrifugal extractor. The flow ratio of organic phase to aqueous phase is controlled to be 1 / 1, so that the organic phase and aqueous phase are subjected to 5-stage countercurrent cascade extraction of rubidium in the 5 centrifuges, and the loaded rubidium organic phase and the extracted rubidium residue are obtained respectively. The residence time of organic phase and aqueous phase in each centrifugal extractor is 0.38 min, and the temperature of the two phases is 20℃ during the extraction process.

[0089] (4) Washing section: Using 0.01 mol / L HCl as the detergent, the rubidium-loaded organic phase is washed in 10 countercurrent stages on a 10-stage centrifugal extractor. The organic phase flows by gravity from the light phase outlet of the 5th stage centrifugal extractor in the extraction section into the light phase inlet of the 1st stage centrifugal extractor in the washing section. The detergent (0.01 mol / L HCl) is pumped into the heavy phase inlet of the 10th stage of the washing section. The flow ratio of organic phase to detergent is controlled at 12 / 1. The washing residue and the purified rubidium-loaded organic phase are obtained respectively. The collected washing residue is pumped to the heavy phase inlet of the 5th stage centrifugal extractor in the extraction section for further extraction. The residence time of the organic phase and detergent in each stage centrifugal extractor is 0.70 min. The temperature of the two phases during the washing process is 20℃.

[0090] (5) Back-extraction section: Using 1.0 mol / L HCl solution as the back-extraction agent, a two-stage countercurrent back-extraction of the cesium-loaded organic phase is carried out on a two-stage centrifugal extractor. The organic phase flows by gravity from the light phase outlet of the 10th stage centrifugal extractor in the washing section into the light phase inlet of the 1st stage centrifugal extractor in the back-extraction section. The back-extraction agent (1.0 mol / L HCl solution) is pumped into the heavy phase inlet of the 2nd stage of the back-extraction section. The flow ratio of organic phase to washing agent is controlled at 50 / 1. Rubidium chloride-enriched back-extraction solution and blank organic phase are obtained respectively. Rubidium chloride-enriched back-extraction solution is used to prepare rubidium chloride products. The collected blank organic phase is pumped to the light phase inlet of the 1st centrifuge in the extraction section for the next extraction cycle. The residence time of the organic phase and back-extraction solution in each stage centrifugal extractor is 0.75 min. The temperature of the two phases during the back-extraction process is 20℃.

[0091] (6) The entire process of extracting and recovering rubidium: The above-mentioned extraction-washing-back-extraction process is repeated to form the entire process of extracting and recovering rubidium from lithium extraction tail liquid.

[0092] Testing revealed that the rubidium extraction rate in the extraction section reached 98.46%, the washing efficiency of potassium, sodium, and lithium in the washing section all exceeded 99%, the average rubidium loss rate in the washing section was 24.17%, the rubidium back-extraction rate in the back-extraction section exceeded 99%, and the purity of the obtained enriched rubidium chloride back-extraction solution was 99.11%. After the washing solution reflux extraction process, the total rubidium yield was over 98%.

[0093] Example 2:

[0094] (a) Cesium extraction process:

[0095] (1) Aqueous raw materials: Sodium hydroxide was dissolved in the lithium extraction tailings with Cs, Rb, Na, K, and Li concentrations of 0.63, 5.75, 41.2, 5.85, and 1.43 g / L, respectively, to make OH... - The concentration was 0.02 mol / L, which was used as the aqueous feed solution for cesium extraction.

[0096] (2) Organic phase raw materials: t-BAMBP was dissolved in cyclohexane as the organic phase for cesium extraction, and the concentration of t-BAMBP was 0.2 mol / L.

[0097] (3) Extraction section: The above-mentioned organic phase is pumped into the light phase inlet of the first centrifuge in the extraction section, and the aqueous phase is pumped into the heavy phase inlet of the fifth centrifugal extractor. The flow ratio of organic phase to aqueous phase is controlled to be 4 / 1, so that the organic phase and aqueous phase are subjected to 5-stage countercurrent cascade extraction of cesium in the 5 centrifuges, and the cesium-loaded organic phase and the cesium extraction residue are obtained respectively. The residence time of organic phase and aqueous phase in each centrifugal extractor is 0.25 min, and the temperature of the two phases is 40℃ during the extraction process.

[0098] (4) Washing section: Using 0.002 mol / L cesium hydroxide as detergent, the organic phase loaded with cesium is washed in a 5-stage countercurrent process on a 5-stage centrifugal extractor. The organic phase flows by gravity from the light phase outlet of the 5th stage centrifugal extractor in the extraction section into the light phase inlet of the 1st stage centrifugal extractor in the washing section. Detergent (deionized water) is pumped into the heavy phase inlet of the 5th stage centrifugal extractor in the washing section. The flow ratio of organic phase to detergent is controlled at 1 / 1. Washing residue and purified cesium-loaded organic phase are obtained respectively. The collected washing residue is pumped to the heavy phase inlet of the 5th stage centrifugal extractor in the extraction section for further extraction. The residence time of organic phase and detergent in each stage centrifugal extractor is 0.16 min. The temperature of the two phases during the washing process is 40℃.

[0099] (5) Back-extraction section: Using 0.3 mol / L HCl solution as the back-extraction agent, a 5-stage countercurrent back-extraction of the cesium-loaded organic phase is carried out on a 5-stage centrifugal extractor. The organic phase flows by gravity from the light phase outlet of the 5th stage centrifugal extractor in the washing section into the light phase inlet of the 1st stage centrifugal extractor in the back-extraction section. The back-extraction agent (0.3 mol / L HCl solution) is pumped into the heavy phase inlet of the 5th stage of the back-extraction section. The flow ratio of organic phase to washing agent is controlled at 50 / 1. Cesium sulfate-enriched back-extraction solution and blank organic phase are obtained respectively. Cesium chloride-enriched back-extraction solution is used to prepare cesium chloride product. The collected blank organic phase is pumped to the light phase inlet of the 1st centrifuge in the extraction section for the next extraction cycle. The residence time of the organic phase and back-extraction solution in each stage centrifugal extractor is 0.31 min. The temperature of the two phases during the back-extraction process is 40℃.

[0100] (6) Extraction and recovery of cesium: The above extraction-washing-back-extraction process is repeated to form a complete process for extracting and recovering cesium from lithium extraction tail liquid.

[0101] Testing revealed that the cesium extraction rate in the extraction section reached 98.67%, the washing efficiency of rubidium, potassium, sodium, and lithium in the washing section all exceeded 98%, there was no cesium loss in the washing section, and the cesium back-extraction rate in the back-extraction section exceeded 99%. The purity of the obtained cesium chloride enriched back-extraction solution was 99.14%, and the total cesium yield was over 98%.

[0102] (II) Rubidium Extraction Process:

[0103] (1) Aqueous phase feedstock: Dissolve sodium hydroxide in the cesium extraction residue to make OH... - The concentration was 1.2 mol / L. The precipitated salt was removed by filtration, and the filtrate was used as the aqueous feed solution for rubidium extraction.

[0104] (2) Organic phase raw materials: t-BAMBP was dissolved in sulfonated kerosene as the rubidium organic phase for extraction, and the concentration of t-BAMBP was 2 mol / L.

[0105] (3) Extraction section: The above-mentioned organic phase is pumped into the light phase inlet of the first centrifuge in the extraction section, and the aqueous phase is pumped into the heavy phase inlet of the second centrifugal extractor. The flow ratio of organic phase to aqueous phase is controlled to be 5 / 1, so that the organic phase and aqueous phase are subjected to two-stage countercurrent cascade extraction of rubidium in the two centrifuges, and the loaded rubidium organic phase and the extracted rubidium residue are obtained respectively. The residence time of organic phase and aqueous phase in each centrifugal extractor is 0.21 min, and the temperature of the two phases is 40℃ during the extraction process.

[0106] (4) Washing section: Using 0.65 mol / L H2SO4 as the detergent, the rubidium-loaded organic phase is washed in 8 stages of countercurrent washing on an 8-stage centrifugal extractor. The organic phase flows by gravity from the light phase outlet of the second stage centrifugal extractor in the extraction section into the light phase inlet of the first stage centrifugal extractor in the washing section. The detergent (0.65 mol / L H2SO4) is pumped into the heavy phase inlet of the eighth stage of the washing section. The flow ratio of organic phase to detergent is controlled at 50 / 1. The washing residue and the purified rubidium-loaded organic phase are obtained respectively. The collected washing residue is pumped to the heavy phase inlet of the second stage centrifugal extractor in the extraction section for further extraction. The residence time of the organic phase and detergent in each stage centrifugal extractor is 0.25 min. The temperature of the two phases during the washing process is 40℃.

[0107] (5) Back-extraction section: Using 0.2 mol / L H2SO4 solution as the back-extraction agent, a 6-stage countercurrent back-extraction of the cesium-loaded organic phase is carried out on a 6-stage centrifugal extractor. The organic phase flows by gravity from the light phase outlet of the 8th stage centrifugal extractor in the washing section into the light phase inlet of the 1st stage centrifugal extractor in the back-extraction section. The back-extraction agent (0.2 mol / L H2SO4 solution) is pumped into the heavy phase inlet of the 6th stage of the back-extraction section. The flow ratio of organic phase to washing agent is controlled at 15 / 1. Rubidium sulfate-enriched back-extraction solution and blank organic phase are obtained respectively. Rubidium sulfate-enriched back-extraction solution is used to prepare rubidium sulfate product. The collected blank organic phase is pumped to the light phase inlet of the 1st centrifuge in the extraction section for the next extraction cycle. The residence time of the organic phase and back-extraction solution in each stage centrifugal extractor is 0.24 min. The temperature of the two phases during the back-extraction process is 40℃.

[0108] (6) The entire process of extracting and recovering rubidium: The above-mentioned extraction-washing-back-extraction process is repeated to form the entire process of extracting and recovering rubidium from lithium extraction tail liquid.

[0109] Testing revealed that the rubidium extraction rate in the extraction section reached 93.21%, the washing efficiency of potassium, sodium, and lithium in the washing section all exceeded 99%, the average rubidium loss rate in the washing section was 29.24%, the rubidium back-extraction rate in the back-extraction section exceeded 99%, and the purity of the obtained rubidium sulfate back-extraction solution was 99.23%. After the washing solution reflux extraction process, the total rubidium yield was over 92%.

[0110] Example 3:

[0111] (a) Cesium extraction process:

[0112] (1) Aqueous raw materials: Sodium hydroxide was dissolved in the lithium extraction tailings with Cs, Rb, Na, K, and Li concentrations of 2.26, 0.35, 64.5, 11.7, and 6.76 g / L, respectively, to make OH... - A concentration of 0.15 mol / L was used as the aqueous feed solution for cesium extraction.

[0113] (2) Organic phase raw materials: t-BAMBP was dissolved in tricresylene as the organic phase for cesium extraction, and the concentration of t-BAMBP was 0.6 mol / L.

[0114] (3) Extraction section: The above-mentioned organic phase is pumped into the light phase inlet of the first centrifuge in the extraction section, and the aqueous phase is pumped into the heavy phase inlet of the eighth centrifugal extractor. The flow ratio of organic phase to aqueous phase is controlled to be 2 / 1, so that the organic phase and aqueous phase are subjected to 8-stage countercurrent cascade extraction of cesium in the 8 centrifuges, and the loaded cesium organic phase and the cesium extraction residue are obtained respectively. The residence time of organic phase and aqueous phase in each centrifugal extractor is 0.25 min, and the temperature of the two phases is 25℃ during the extraction process.

[0115] (4) Washing section: Using 1 mol / L cesium nitrate solution as detergent, the organic phase loaded with cesium is washed in a 4-stage countercurrent centrifugal extractor. The organic phase flows by gravity from the light phase outlet of the 8th stage centrifugal extractor in the extraction section into the light phase inlet of the 1st stage centrifugal extractor in the washing section. The detergent (1 mol / L cesium nitrate solution) is pumped into the heavy phase inlet of the 4th stage of the washing section. The flow ratio of organic phase to detergent is controlled at 10 / 1. The washing residue and the purified cesium-loaded organic phase are obtained respectively. The collected washing residue is pumped to the heavy phase inlet of the 8th stage centrifugal extractor in the extraction section for further extraction. The residence time of the organic phase and detergent in each stage centrifugal extractor is 0.35 min. The temperature of the two phases during the washing process is 25℃.

[0116] (5) Back-extraction section: Using 3.6 mol / L HNO3 solution as the back-extraction agent, a 5-stage countercurrent back-extraction of the cesium-loaded organic phase is carried out on a 5-stage centrifugal extractor. The organic phase flows by gravity from the light phase outlet of the 4th stage centrifugal extractor in the washing section into the light phase inlet of the 1st stage centrifugal extractor in the back-extraction section. The back-extraction agent (3.6 mol / L HNO3 solution) is pumped into the heavy phase inlet of the 5th stage of the back-extraction section. The flow ratio of organic phase to washing agent is controlled at 30 / 1. Cesium-enriched back-extraction solution and blank organic phase are obtained respectively. The cesium-enriched back-extraction solution is used to prepare cesium nitrate products. The collected blank organic phase is pumped to the light phase inlet of the 1st centrifuge in the extraction section for the next extraction cycle. The residence time of the organic phase and back-extraction solution in each stage centrifugal extractor is 0.37 min. The temperature of the two phases during the back-extraction process is 25℃.

[0117] (6) Extraction and recovery of cesium: The above extraction-washing-back-extraction process is repeated to form a complete process for extracting and recovering cesium from lithium extraction tail liquid.

[0118] Testing revealed that the cesium extraction rate in the extraction section reached 99.89%, the washing efficiency of rubidium, potassium, sodium, and lithium in the washing section all exceeded 98%, there was no cesium loss in the washing section, and the cesium back-extraction rate in the back-extraction section exceeded 98%. The purity of the obtained cesium nitrate enriched back-extraction solution was 98.07%, and the total cesium yield was over 98%.

[0119] (II) Rubidium Extraction Process:

[0120] (1) Aqueous phase feedstock: Dissolve potassium hydroxide in the cesium extraction residue to make OH... - The concentration was 0.4 mol / L. The precipitated salt was removed by filtration, and the filtrate was used as the aqueous feed solution for rubidium extraction.

[0121] (2) Organic phase raw materials: t-BAMBP was dissolved in tricresylene as the rubidium organic phase for extraction, and the concentration of t-BAMBP was 1.5 mol / L.

[0122] (3) Extraction section: The above-mentioned organic phase is pumped into the light phase inlet of the first centrifuge in the extraction section, and the aqueous phase is pumped into the heavy phase inlet of the fifth centrifugal extractor. The flow ratio of organic phase to aqueous phase is controlled to be 1 / 5, so that the organic phase and aqueous phase are subjected to 5-stage countercurrent cascade extraction of rubidium in the 5 centrifuges, and the loaded rubidium organic phase and the extracted rubidium residue are obtained respectively. The residence time of organic phase and aqueous phase in each centrifugal extractor is 0.63 min, and the temperature of the two phases is 25℃ during the extraction process.

[0123] (4) Washing section: Using 0.15 mol / L rubidium hydroxide as the detergent, the rubidium-loaded organic phase is washed in 15 countercurrent stages on a 15-stage centrifugal extractor. The organic phase flows by gravity from the light phase outlet of the 5th stage centrifugal extractor in the extraction section into the light phase inlet of the 1st stage centrifugal extractor in the washing section. The detergent (0.15 mol / L rubidium hydroxide) is pumped into the heavy phase inlet of the 15th stage of the washing section. The flow ratio of organic phase to detergent is controlled at 3 / 1. The washing residue and the purified rubidium-loaded organic phase are obtained respectively. The collected washing residue is pumped to the heavy phase inlet of the 5th stage centrifugal extractor in the extraction section for further extraction. The residence time of the organic phase and detergent in each stage centrifugal extractor is 2.85 min. The temperature of the two phases during the washing process is 25℃.

[0124] (5) Back-extraction section: Using 0.1 mol / L HNO3 solution as the back-extraction agent, a 6-stage countercurrent back-extraction of the cesium-loaded organic phase is carried out on a 3-stage centrifugal extractor. The organic phase flows by gravity from the light phase outlet of the 8th stage centrifugal extractor in the washing section into the light phase inlet of the 1st stage centrifugal extractor in the back-extraction section. The back-extraction agent (0.1 mol / L HNO3 solution) is pumped into the heavy phase inlet of the 3rd stage of the back-extraction section. The flow ratio of the organic phase and the washing agent is controlled at 1 / 1. Rubidium nitrate-enriched back-extraction solution and blank organic phase are obtained respectively. The rubidium nitrate-enriched back-extraction solution is used to prepare rubidium nitrate products. The collected blank organic phase is pumped to the light phase inlet of the 1st centrifuge in the extraction section for the next extraction cycle. The residence time of the organic phase and back-extraction solution in each stage centrifugal extractor is 1.9 min. The temperature of the two phases during the back-extraction process is 25℃.

[0125] (6) The entire process of extracting and recovering rubidium: The above-mentioned extraction-washing-back-extraction process is repeated to form the entire process of extracting and recovering rubidium from lithium extraction tail liquid.

[0126] Testing revealed that the rubidium extraction rate in the extraction section reached 94.67%, the washing efficiency of potassium, sodium, and lithium in the washing section all exceeded 99%, there was no rubidium loss in the washing section, and the rubidium back-extraction rate in the back-extraction section exceeded 99%. The purity of the obtained rubidium-enriched nitrate back-extraction solution was 98.43%. After the washing solution was refluxed and extracted, the total rubidium yield was over 94%.

[0127] Example 4:

[0128] (a) Cesium extraction process:

[0129] (1) Aqueous raw materials: Sodium hydroxide was dissolved in the lithium extraction tailings with Cs, Rb, Na, K, and Li concentrations of 8.62, 17.4, 22.5, 46.8, and 4.55 g / L, respectively, to make OH... - The concentration was 0.6 mol / L. The precipitated salt was removed by filtration, and the filtrate was used as the aqueous feed solution for cesium extraction.

[0130] (2) Organic phase raw materials: t-BAMBP was dissolved in sulfonated kerosene as the organic phase for cesium extraction, and the concentration of t-BAMBP was 1.5 mol / L.

[0131] (3) Extraction section: The above-mentioned organic phase is pumped into the light phase inlet of the first centrifuge in the extraction section, and the aqueous phase is pumped into the heavy phase inlet of the fifth centrifugal extractor. The flow ratio of organic phase to aqueous phase is controlled to be 4 / 1, so that the organic phase and aqueous phase are subjected to 5-stage countercurrent cascade extraction of cesium in the 5 centrifuges, and the cesium-loaded organic phase and the cesium extraction residue are obtained respectively. The residence time of organic phase and aqueous phase in each centrifugal extractor is 0.38 min, and the temperature of the two phases is 60℃ during the extraction process.

[0132] (4) Washing section: Using 1 mol / L HCl solution as the detergent, the cesium-loaded organic phase is washed in 10 countercurrent stages on a 10-stage centrifugal extractor. The organic phase flows by gravity from the light phase outlet of the 5th stage centrifugal extractor in the extraction section into the light phase inlet of the 1st stage centrifugal extractor in the washing section. The detergent (1 mol / L HCl solution) is pumped into the heavy phase inlet of the 10th stage of the washing section. The flow ratio of organic phase to detergent is controlled at 20 / 1. The washing residue and the purified cesium-loaded organic phase are obtained respectively. The collected washing residue is pumped to the heavy phase inlet of the 5th stage centrifugal extractor in the extraction section for further extraction. The residence time of the organic phase and detergent in each stage centrifugal extractor is 0.45 min. The temperature of the two phases during the washing process is 60℃.

[0133] (5) Back-extraction section: Using 1 mol / L HCl solution as the back-extraction agent, a three-stage countercurrent back-extraction of the cesium-loaded organic phase is carried out on a three-stage centrifugal extractor. The organic phase flows by gravity from the light phase outlet of the tenth-stage centrifugal extractor in the washing section into the light phase inlet of the first-stage centrifugal extractor in the back-extraction section. The back-extraction agent (1 mol / L HCl solution) is pumped into the heavy phase inlet of the third stage of the back-extraction section. The flow ratio of the organic phase to the washing agent is controlled at 50 / 1. Cesium chloride-enriched back-extraction solution and blank organic phase are obtained respectively. The cesium chloride-enriched back-extraction solution is used to prepare cesium chloride products. The collected blank organic phase is pumped to the light phase inlet of the first centrifuge in the extraction section for the next extraction cycle. The residence time of the organic phase and back-extraction solution in each centrifugal extractor is 0.47 min. The temperature of the two phases during the back-extraction process is 60℃.

[0134] (6) Extraction and recovery of cesium: The above extraction-washing-back-extraction process is repeated to form a complete process for extracting and recovering cesium from lithium extraction tail liquid.

[0135] Testing revealed that the cesium extraction rate in the extraction section reached 99.70%, the washing efficiency of rubidium, potassium, sodium, and lithium in the washing section all exceeded 99%, the cesium loss rate in the washing section was 33.45%, the cesium back-extraction rate in the back-extraction section exceeded 99%, the purity of the obtained cesium chloride enriched back-extraction solution was 99.87%, and the total cesium yield was over 98%.

[0136] (II) Rubidium Extraction Process:

[0137] (1) Aqueous phase feedstock: Dissolve sodium hydroxide in the cesium extraction residue to make OH... - The concentration was 1.5 mol / L. The precipitated salt was removed by filtration, and the filtrate was used as the aqueous feed solution for rubidium extraction.

[0138] (2) Organic phase raw materials: t-BAMBP was dissolved in sulfonated kerosene as the rubidium organic phase for extraction, and the concentration of t-BAMBP was 2 mol / L.

[0139] (3) Extraction section: The above-mentioned organic phase is pumped into the light phase inlet of the first centrifuge in the extraction section, and the aqueous phase is pumped into the heavy phase inlet of the eighth centrifugal extractor. The flow ratio of organic phase to aqueous phase is controlled to be 4 / 1, so that the organic phase and aqueous phase are subjected to 8-stage countercurrent cascade extraction of rubidium in the 8 centrifuges, and the loaded rubidium organic phase and the extracted rubidium residue are obtained respectively. The residence time of organic phase and aqueous phase in each centrifugal extractor is 0.38 min, and the temperature of the two phases is 60℃ during the extraction process.

[0140] (4) Washing section: Using 1.6 mol / L H2SO4 solution as the washing agent, the rubidium-loaded organic phase is washed in 12 countercurrent stages on a 12-stage centrifugal extractor. The organic phase flows by gravity from the light phase outlet of the 8th stage centrifugal extractor in the extraction section into the light phase inlet of the 1st stage centrifugal extractor in the washing section. The washing agent (1.6 mol / L H2SO4) is pumped into the heavy phase inlet of the 12th stage of the washing section. The flow ratio of organic phase to washing agent is controlled at 30 / 1. The washing residue and the purified rubidium-loaded organic phase are obtained respectively. The collected washing residue is pumped to the heavy phase inlet of the 8th stage centrifugal extractor in the extraction section for further extraction. The residence time of the organic phase and washing agent in each stage centrifugal extractor is 0.46 min. The temperature of the two phases during the washing process is 60℃.

[0141] (5) Back-extraction section: Using 1.6 mol / L H2SO4 solution as the back-extraction agent, a 6-stage countercurrent back-extraction of the cesium-loaded organic phase is carried out on a 6-stage centrifugal extractor. The organic phase flows by gravity from the light phase outlet of the 12th stage centrifugal extractor in the washing section into the light phase inlet of the 1st stage centrifugal extractor in the back-extraction section. The back-extraction agent (1.6 mol / L H2SO4 solution) is pumped into the heavy phase inlet of the 6th stage of the back-extraction section. The flow ratio of the organic phase to the washing agent is controlled at 50 / 1. Rubidium sulfate-enriched back-extraction solution and blank organic phase are obtained respectively. The rubidium sulfate-enriched back-extraction solution is used to prepare rubidium sulfate products. The collected blank organic phase is pumped to the light phase inlet of the first centrifuge in the extraction section for the next extraction cycle. The residence time of the organic phase and back-extraction solution in each stage centrifugal extractor is 0.47 min. The temperature of the two phases during the back-extraction process is 60℃.

[0142] (6) The entire process of extracting and recovering rubidium: The above-mentioned extraction-washing-back-extraction process is repeated to form the entire process of extracting and recovering rubidium from lithium extraction tail liquid.

[0143] Testing revealed that the rubidium extraction rate in the extraction section reached 98.71%, the washing efficiency of potassium, sodium, and lithium in the washing section all exceeded 99%, the rubidium loss rate in the washing section was 18.87%, and the rubidium back-extraction rate in the back-extraction section exceeded 99%. The purity of the obtained rubidium sulfate back-extraction solution was 99.52%. After the washing solution was refluxed and extracted, the total rubidium yield was over 98%.

[0144] All aspects, embodiments, features, and examples of this invention are to be regarded as illustrative in all respects and are not intended to limit the invention, the scope of which is defined only by the claims. Other embodiments, modifications, and uses will become apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0145] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0146] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that elements of the embodiments can be substituted with substantially equivalents. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this invention is not intended to be limited to the specific embodiments disclosed for carrying out the invention, but rather is intended to encompass all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated otherwise, any use of the terms first, second, etc., does not indicate any order or importance, but is used to distinguish one element from another.

Claims

1. A method for extracting and recovering cesium and rubidium from lithium extraction tailings from ore using centrifugal extraction, characterized in that, include: The tailings of lithium extraction from ore containing at least rubidium, cesium, sodium, potassium, and lithium are adjusted with an alkaline substance, filtered, and the filtrate is used as the aqueous raw material for cesium extraction. The concentration of rubidium in the tailings of lithium extraction from ore is 0.05 g / L to 20 g / L, the concentration of cesium is 0.05 g / L to 10 g / L, the concentration of sodium is 0 to 100 g / L, the concentration of potassium is 0 to 100 g / L, and the concentration of lithium is 0 to 40 g / L. A first extractable organic phase comprising an extractant and a diluent is provided, and the first extractable organic phase and the aqueous cesium-extracting feedstock are jointly fed into a centrifugal extractor for multi-stage countercurrent cascade extraction to obtain a cesium-loaded organic phase and a cesium-extracting residue; wherein, the flow ratio of the first extractable organic phase to the aqueous cesium-extracting feedstock is 1:5 to 5:1, the number of extraction stages is 2 to 8, the residence time of the first extractable organic phase and the aqueous cesium-extracting feedstock in each stage of the centrifugal extractor is 0.1 to 5 min, and the temperature of the two phases during the extraction process is 20 to 60 °C; the extractant includes 4-tert-butyl-2-(α-methylbenzyl)phenol; The cesium-loaded organic phase was washed with a first detergent in a multi-stage centrifugal extractor to obtain a pure cesium-loaded organic phase. The purified cesium-loaded organic phase is fed into a multi-stage centrifugal extractor and cesium is back-extracted with a back-extraction agent to obtain a cesium-rich solution. The solution is then evaporated, concentrated, and crystallized to obtain cesium salt. The cesium extraction residue was adjusted with an alkaline substance, filtered, and the filtrate was used as the aqueous phase raw material for rubidium extraction. A second extractable organic phase comprising an extractant and a diluent is provided, and the second extractable organic phase and the aqueous extractant of rubidium are co-feeded into a centrifugal extractor for multi-stage countercurrent cascade extraction to obtain a rubidium-loaded organic phase and rubidium-extracted residue; wherein the flow ratio of the second extractable organic phase to the aqueous extractant of rubidium is 1:5 to 5:1, the number of extraction stages is 2 to 8, the residence time of the second extractable organic phase and the aqueous extractant of rubidium in each centrifugal extractor stage is 0.1 to 5 min, and the temperature of the two phases during the extraction process is 20 to 60 °C; the extractant includes 4-tert-butyl-2-(α-methylbenzyl)phenol; The supported rubidium organic phase was washed with a second detergent in a multi-stage centrifugal extractor to obtain a pure supported rubidium organic phase. The purified rubidium-loaded organic phase is fed into a multi-stage centrifugal extractor and back-extracted with a back-extracting agent to obtain a rubidium-enriched solution. The solution is then evaporated, concentrated, and crystallized to obtain rubidium salt.

2. The method according to claim 1, characterized in that: The tailings from the lithium extraction of the ore may also selectively include any one or a combination of two or more of the following: calcium ions, magnesium ions, iron ions, aluminum ions, chloride ions, sulfate ions, nitrate ions, and carbonate ions.

3. The method according to claim 1, characterized in that... include: The OH- concentration of the lithium extraction tailings from the ore was adjusted to 0.01–1 mol / L with an alkaline substance, filtered, and the filtrate was used as the aqueous raw material for cesium extraction. And / or, the method includes: adjusting the OH- concentration of the cesium extraction residue to 0.1-2 mol / L with an alkaline substance, filtering, and using the filtrate as an aqueous raw material for rubidium extraction; And / or, the alkaline substance includes at least one of sodium hydroxide, potassium hydroxide, and lithium hydroxide.

4. The method according to claim 1, characterized in that: The concentration of the extractant in the diluent in the first organic phase of extraction is 0.1–2.0 mol / L; and / or the concentration of the extractant in the diluent in the second organic phase of extraction is 0.2–2.0 mol / L; and / or the diluent includes at least one of sulfonated kerosene, cyclohexane, cyclohexanone, benzene, toluene, xylene, and trimethylbenzene.

5. The method according to claim 1, characterized in that, include: The cesium-loaded organic phase is washed and purified using a first detergent in a multi-stage centrifugal extractor. The first detergent includes any one of deionized water, cesium chloride solution, cesium sulfate solution, cesium nitrate solution, cesium hydroxide solution, and acid solution. And / or, the number of washing stages is 2 to 15, the washing flow ratio is 50:1 to 1:1, the residence time of the cesium-loaded organic phase and the first detergent in each centrifugal extractor is 0.1 to 5 min, and the temperature of the two phases during the washing process is 20 to 60°C.

6. The method according to claim 5, characterized in that: When the first detergent is any one of cesium chloride solution, cesium sulfate solution, cesium nitrate solution, or cesium hydroxide solution, the concentration is 0.001 to 1 mol / L; and / or, when the first detergent is an acid solution, the acid includes any one of acetic acid, nitric acid, hydrochloric acid, sulfuric acid, or carbonic acid, and the acid concentration is 0.001 to 1 mol / L; And / or, the method further includes: after washing the cesium-loaded organic phase, transferring the obtained first washing residue back to the cesium extraction section to continue cesium extraction.

7. The method according to claim 1, characterized in that: In the cesium extraction process, the back-extraction agent includes any one of acetic acid, nitric acid, hydrochloric acid, carbonic acid, and sulfuric acid, with an acid concentration of 0.01–4 mol / L; and / or, the number of back-extraction stages is 2–6, the washing flow ratio is 50:1–1:1, the residence time of the pure cesium-loaded organic phase and the back-extraction agent in each stage centrifugal extractor is 0.1–5 min, and the temperature of the two phases during the back-extraction process is 20–60 °C; And / or, the cesium salt includes any one of cesium acetate, cesium nitrate, cesium chloride, cesium carbonate, and cesium sulfate; And / or, in the cesium extraction process, extraction, washing, and cesium back-extraction are all performed in countercurrent cascade operation using multiple centrifugal extractors.

8. The method according to claim 1, characterized in that, include: The rubidium-loaded organic phase is washed and purified using a second detergent in a multi-stage centrifugal extractor. The second detergent includes any one of deionized water, rubidium chloride solution, rubidium sulfate solution, rubidium nitrate solution, rubidium hydroxide solution, and acid solution. And / or, the number of washing stages is 2 to 15, the washing flow ratio is 50:1 to 1:1, the residence time of the rubidium-loaded organic phase and the second detergent in each centrifugal extractor is 0.1 to 5 min, and the temperature of the two phases during the washing process is 20 to 60°C.

9. The method according to claim 8, characterized in that: When the second detergent is any one of rubidium chloride solution, rubidium sulfate solution, rubidium nitrate solution, or rubidium hydroxide solution, the concentration is 0.001–1 mol / L; and / or, when the second detergent is an acid solution, the acid includes any one of acetic acid, nitric acid, hydrochloric acid, sulfuric acid, or carbonic acid, and the acid concentration is 0.001–2 mol / L. And / or, the method further includes: after washing the rubidium-loaded organic phase, conveying the obtained second washing residue back to the rubidium extraction section to continue extracting rubidium.

10. The method according to claim 1, characterized in that: In the rubidium extraction process, the back-extraction agent includes any one of acetic acid, nitric acid, hydrochloric acid, carbonic acid, and sulfuric acid, with an acid concentration of 0.01–4 mol / L; and / or, the number of back-extraction stages is 2–6, the washing flow ratio is 50:1–1:1, the residence time of the pure rubidium-loaded organic phase and the back-extraction agent in each centrifugal extractor is 0.1–5 min, and the temperature of the two phases during the back-extraction process is 20–60 °C; And / or, the rubidium salt includes any one of rubidium acetate, rubidium nitrate, rubidium chloride, rubidium carbonate, and rubidium sulfate; And / or, in the rubidium extraction process, extraction, washing, and cesium back-extraction are all performed in countercurrent cascade operation using multiple centrifugal extractors.

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