Ion chelating system and separation method for extracting and separating lithium ions from an alkaline high-sodium solution

Abstract

The application provides an ion chelation system and a separation method for extracting and separating lithium ions from an alkaline high-sodium solution, and belongs to the technical field of hydrometallurgy. The separation system is composed of a chelating agent and a diluent. The chelating agent is one or more of R1COCR2R3COR4, R1CSCR2R3CSR4, R1CSC=CCSR4, R1R2NCS (CH2) n CSNR3R4, and the diluent is a hydrocarbon compound. The ion chelation system solves the problem of low selectivity separation caused by high sodium and potassium ions and similar chemical properties in a lithium-rubidium-caesium solution. The system can efficiently and selectively chelate lithium-rubidium-caesium, thereby achieving deep separation of sodium and potassium from lithium-rubidium-caesium, significantly improving the recovery rate and product purity of lithium-rubidium-caesium, and realizing a green and environmentally-friendly process.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgical technology, and more specifically, to an ion chelation system and separation method for extracting and separating lithium ions from an alkaline high-sodium solution. Background Technology

[0002] Lithium-ion separation technology is a core technology for addressing the demands of the new energy industry and overcoming the limitations of traditional lithium extraction methods. Its core principle is the highly selective separation of lithium ions from sources such as salt lake brine, lithium mines, and spent batteries. Lithium, as a key material in the new energy field, is listed as a strategic mineral. With the expansion of the new energy vehicle and energy storage industries, global lithium demand has surged, widening the supply-demand gap. Rubidium and cesium are key strategic rare metals, widely used in atomic clocks, navigation, new energy, and electronic materials.

[0003] Industry demand, resource security, environmental policies, and technological iteration are the driving forces behind its development. In the future, it will make breakthroughs in the direction of green, high efficiency, and low consumption to support the sustainable supply of lithium, rubidium, and cesium resources.

[0004] Traditional precipitation and ion exchange methods suffer from poor selectivity, high cost, and difficulty in continuous operation, making them unsuitable for large-scale production. Solvent extraction, with its advantages of high selectivity, large throughput, and continuous operation, has become the mainstream industrial technology. Its core principle is to utilize the difference in partition coefficients to achieve efficient separation and enrichment of rubidium / cesium from impurities, which is a key technological approach to solving the problems of resource dispersion and interference from symbiotic organisms.

[0005] Therefore, a highly efficient separation method for sodium, potassium, lithium, rubidium, and cesium is needed to meet the requirements of industrial production for lithium, rubidium, and cesium. Thus, an ion chelation system and separation method for extracting and separating lithium ions from an alkaline high-sodium solution are proposed. Summary of the Invention

[0006] The purpose of this invention is to provide an ion chelation system and separation method for extracting and separating lithium ions from alkaline high-sodium solutions. This ion chelation system solves the problem of selective separation caused by the high sodium concentration and similar chemical properties of sodium and lithium in alkaline high-sodium solutions. This system can efficiently and selectively chelate lithium ions, thereby achieving deep separation of lithium and sodium while significantly improving lithium recovery rate and product purity, and the process is green and environmentally friendly.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: an ion chelation system for extracting and separating lithium, rubidium, and cesium ions from an alkaline high-sodium potassium solution, wherein the ion chelation system consists of a chelating agent and a diluent, and the diluent is a hydrocarbon compound.

[0008] As a preferred embodiment of the present invention, the chelating agent has the molecular formulas R1COCR2R3COR4, R1CSCR2R3CSR4, R1CSC=CCSR4, and R1R2NCS(CH2).n One or more of CSNR3R4, wherein R1, R2, R3, and R4 are independently selected from H, OH, or Cl-C. 20 One or more of alkanes, alkenes, cycloalkanes, and aromatic hydrocarbons.

[0009] As a preferred embodiment of the present invention, the hydrocarbon compound is selected from one or more of alkanes, haloalkanes, aromatics, or cycloalkanes.

[0010] As a preferred embodiment of the present invention, the volume ratio of the chelating agent to the diluent is (0.1-10):1.

[0011] This invention also provides a method for separating lithium, rubidium, and cesium ions from an alkaline high-sodium potassium solution using the above-mentioned ion chelation system, comprising the following steps: S1. Chelation separation: The separation system is mixed with an alkaline high sodium potassium solution for ion chelation, and the ion chelated phase containing lithium, rubidium and cesium ions and the sodium potassium aqueous phase after lithium, rubidium and cesium extraction are obtained. S2. Purification and removal of sodium and potassium: Use a purifying agent to purify the ion-chelating organic phase that chelates lithium, rubidium, and cesium ions, and separate the purified ion chelate and the sodium and potassium-containing purified solution. S3. Lithium-rubidium-cesium extraction: The purified ion-chelating organic phase is mixed with the chelating agent to carry out the chelation reaction, which breaks the chelation between lithium-rubidium-cesium ions and the chelating agent, and separates the lithium-rich rubidium-cesium solution and the chelating agent after chelation.

[0012] As a preferred technical solution of the present invention, in step S1, the lithium concentration in the alkaline high-sodium lithium rubidium cesium solution is ≤20g / L, the sodium and potassium concentration is ≤100g / L, and the pH is 10-14.

[0013] As a preferred technical solution of the present invention, in step S1, the volume ratio of the ion-chelated organic phase to the alkaline high sodium potassium solution is 1:10-10:1. As a preferred technical solution of the present invention, in step S2, the volume ratio of the ion-chelated organic phase to the purifying agent is (2-99):1; As a preferred technical solution of the present invention, in step S3, the volume ratio of the purified ion chelating organic phase to the desorbent is (2-20):1.

[0014] As a preferred technical solution of the present invention, the purifying agent in step S2 is one or more of lithium chloride (rubidium / cesium), lithium sulfate (rubidium / cesium), lithium dihydrogen phosphate (rubidium / cesium), lithium phosphate (rubidium / cesium), lithium monohydrogen phosphate (rubidium / cesium), hydrochloric acid, sulfuric acid, and phosphoric acid; As a preferred technical solution of the present invention, in step S3, the eluent is hydrochloric acid, sulfuric acid or phosphoric acid, and the acid concentration of the eluent is 0.1-6 mol / L.

[0015] As a preferred technical solution of the present invention, in steps 1 to 3, the chelation, purification and desorption temperatures are 40-80℃.

[0016] As a preferred technical solution of the present invention, the ion chelation system chelates lithium, rubidium, and cesium ions through tautomerism, selectively extracting lithium ions from alkaline high sodium and potassium solutions, while retaining sodium and potassium ions in the aqueous phase. A small amount of sodium and potassium ions chelated into the chelated organic phase are purified to remove sodium and potassium, further improving the purity of lithium, rubidium, and cesium ions in the chelated organic phase.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This method has high separation efficiency and high selectivity. It has extremely high selectivity for lithium, rubidium and cesium ions, with a separation rate of ≥99%, while the selectivity for sodium and potassium ions is low, with a separation rate of ≤5%, thus achieving sufficient separation of lithium, rubidium and cesium ions and sodium and potassium ions.

[0018] (2) No solid or liquid waste is generated during the production process. All materials are efficiently recycled, which is a typical green and sustainable development route.

[0019] (3) This method is flexible, easy to scale up and operate continuously, and has significant economic benefits. The core ion chelation system can be stably recycled through desorption and conversion, which greatly reduces production costs. The entire production process generates no waste, is environmentally friendly, and has the combined advantages of low cost, high quality and environmental friendliness, and has great prospects and potential for industrial application.

[0020] (4) This method has high desorption efficiency and can achieve high enrichment of lithium, rubidium, and cesium ions. The lithium, rubidium, and cesium concentration in the lithium-rich rubidium and cesium solution obtained by desorption can reach 30 g / L, which greatly reduces the energy and material consumption of subsequent processes. At the same time, it lays the foundation for the direct preparation of lithium sulfate (rubidium / cesium), lithium chloride (rubidium / cesium), and lithium dihydrogen phosphate (rubidium / cesium) products with a purity of over 99%. Attached image description: Figure 1 A flowchart of the method steps provided by the present invention; Figure 2 A block diagram of control parameters for the method steps provided by this invention; Figure 3 This is a data block diagram of the purifying agent and the desorbent provided by the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are specific implementations of the present invention and are not limited to all embodiments.

[0022] Therefore, the following detailed description of embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely illustrates some embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0023] It should be noted that, in the absence of conflict, the embodiments and features and technical solutions in the embodiments of the present invention can be combined with each other. It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] Example 1: This invention provides an ion chelation system and separation method for extracting and separating lithium, rubidium, and cesium ions from an alkaline high-sodium potassium solution. The system consists of a chelating agent and a diluent, wherein the diluent is a hydrocarbon compound.

[0025] Chelating agents have the following molecular formulas: R1COCR2R3COR4, R1CSCR2R3CSR4, R1CSC=CCSR4, and R1R2NCS(CH2). n One or more of CSNR3R4, wherein R1, R2, R3, and R4 are independently selected from H, OH, or Cl-C. 20 One or more of alkanes, alkenes, cycloalkanes, and aromatic hydrocarbons.

[0026] The hydrocarbon compounds are selected from one or more of the following: alkanes, haloalkanes, aromatics, or cycloalkanes.

[0027] The volume ratio of chelating agent to diluent is (0.1-10):1.

[0028] This invention also provides a method for separating lithium, rubidium, and cesium ions from an alkaline high-sodium potassium solution using the above-described ion chelation system, comprising the following steps: S1. Chelation separation: The separation system is mixed with an alkaline high sodium potassium solution for ion chelation, and the ion chelated phase containing lithium, rubidium and cesium ions and the sodium potassium aqueous phase after lithium, rubidium and cesium extraction are obtained. S2. Purification and removal of sodium and potassium: Use a purifying agent to purify the ion-chelating organic phase that chelates lithium, rubidium, and cesium ions, and separate the purified ion chelate and the sodium and potassium-containing purified solution. S3. Lithium, Rubidium, and Cesium Extraction: The purified ion-chelating organic phase is mixed with an eluent to carry out an eluent reaction, which breaks the chelation between lithium ions and the eluent, and separates the lithium-rich rubidium and cesium solution and the eluented chelated organic phase.

[0029] In step S1, the concentration of lithium, rubidium, and cesium in the alkaline high-sodium potassium solution is ≤20 g / L, the concentration of sodium and potassium is ≤100 g / L, and the pH is 10-14.

[0030] In step S1, the volume ratio of the ion-chelated organic phase to the alkaline high-sodium potassium solution is 1:10-10:1. In step S2, the volume ratio of the ion-chelated organic phase to the purifying agent is (2-99):1; In step S3, the volume ratio of the purified ion-chelating organic phase to the eluent is (2-20):1.

[0031] The purifying agent in step S2 is one or more of the following: lithium chloride (rubidium / cesium), lithium sulfate (rubidium / cesium), lithium dihydrogen phosphate (rubidium / cesium), lithium phosphate (rubidium / cesium), lithium monohydrogen phosphate (rubidium / cesium), hydrochloric acid, sulfuric acid, and phosphoric acid; In step S3, the eluent is hydrochloric acid, sulfuric acid, or phosphoric acid, and the concentration of the eluent acid is 0.1-6 mol / L; In steps 1 through 3, the chelation, purification, and desorption temperatures are 40-80℃. Example 2: This example provides an ion chelation system and separation method for extracting and separating lithium, rubidium, and cesium ions from an alkaline high-sodium potassium solution, including the following steps: (1) Preparation of ion chelation system: Take C6H 11 An ion chelation system was prepared by mixing COCH2COC4H9 and D80 at a volume ratio of 3:7.

[0032] (2) Ion chelation system and cesium ion chelation: The ion chelation system obtained in step (1) was mixed with an alkaline high sodium potassium solution at a volume ratio of 1:1, stirred at 60°C for 3 min, and allowed to stand for phase separation. The alkaline high sodium potassium solution had a cesium concentration of 3 g / L, a sodium potassium concentration of 60 g / L, and a pH of 13.1, resulting in an ion chelated organic phase and a sodium potassium aqueous phase. The sodium potassium aqueous phase had a cesium concentration of 17 ppm and a sodium potassium concentration of 59 g / L.

[0033] (3) Purification of the ion-chelated organic phase: The ion-chelated organic phase obtained in step (2) is mixed with a mixed solution of 0.5 mol / L hydrochloric acid and 40 g / L cesium chloride at a volume ratio of 30:1 for purification. The mixture is stirred at 60°C for 3 min to purify the impurities in the ion-chelated organic phase.

[0034] (4) Eluent Eluent of Ion-chelated Organic Phase: The purified ion-chelated organic phase obtained in step (3) was mixed with 8 mol / L hydrochloric acid at a volume ratio of 10:1 and stirred at 60°C for 3 min to break the chelation between cesium ions and the ion exchange system. The cesium ions were transferred to the aqueous phase, resulting in a lithium-rich solution. The cesium concentration in the eluent was 30 g / L, the sodium and potassium concentration was 0.5 ppm, and the product purity was 99.3%.

[0035] Example 3: This example provides an ion chelation system and separation method for extracting and separating lithium, rubidium, and cesium ions from an alkaline high-sodium potassium solution, including the following steps: (1) Preparation of ion chelation system: C4H9CSCH2CSC2H5 and white oil were mixed at a volume ratio of 2:6 to prepare ion chelation system.

[0036] (2) Ion chelation system and rubidium ion chelation: The ion chelation system obtained in step (1) was mixed with an alkaline high sodium potassium solution at a volume ratio of 2:1, stirred at 50°C for 3 min, and allowed to stand for phase separation. The alkaline high sodium potassium solution had a lithium concentration of 6 g / L, a sodium potassium concentration of 80 g / L, and a pH of 13.5, resulting in an ion chelated organic phase and a sodium potassium aqueous phase. The sodium potassium aqueous phase contained rubidium at a concentration of 25 ppm and sodium potassium at a concentration of 78 g / L.

[0037] (3) Purification of the ion-chelated organic phase: The ion-chelated organic phase obtained in step (2) is mixed with a mixed solution of 0.4 mol / L sulfuric acid and 40 g / L rubidium sulfate at a volume ratio of 50:1 for purification. The mixture is stirred at 50°C for 3 min to purify the impurities in the ion-chelated organic phase.

[0038] (4) Eluent Eluent of Ion-chelated Organic Phase: The purified ion-chelated organic phase obtained in step (3) was mixed with 6 mol / L sulfuric acid at a volume ratio of 12:1 and stirred at 50°C for 3 min to break the chelation between rubidium ions and the ion exchange system. The rubidium ions were transferred to the aqueous phase, resulting in a rubidium-rich solution. The rubidium concentration in the eluent was 36 g / L, the sodium and potassium concentration was 0.8 ppm, and the product purity was 99.2%.

[0039] Example 4: This example provides an ion chelation system and separation method for extracting and separating lithium, rubidium, and cesium ions from an alkaline high-sodium potassium solution, including the following steps: (1) Preparation of ion chelation system: CH3C2H5NCS(CH2)3CSNCH3C3H7 and hexadecane chloro were mixed in a volume ratio of 4:6 to prepare ion chelation system.

[0040] (2) Ion chelation system and lithium ion chelation: The ion chelation system obtained in step (1) was mixed with an alkaline high sodium potassium solution at a volume ratio of 1.2:1, stirred at 40°C for 3 min, and allowed to stand for phase separation. The alkaline high sodium potassium solution had a lithium concentration of 4 g / L, a sodium potassium concentration of 70 g / L, and a pH of 13.3, resulting in an ion chelation organic phase and a sodium potassium aqueous phase. The sodium potassium aqueous phase had a lithium concentration of 20 ppm and a sodium potassium concentration of 69 g / L.

[0041] (3) Purification of the ion-chelated organic phase: The ion-chelated organic phase obtained in step (2) is mixed with a mixed solution of 0.7 mol / L phosphoric acid and 50 g / L lithium dihydrogen phosphate at a volume ratio of 30:1 for purification. The mixture is stirred at 40°C for 3 min to purify the impurities in the ion-chelated organic phase.

[0042] (4) Eluent Eluent of Ion-chelated Organic Phase: The purified ion-chelated organic phase obtained in step (3) was mixed with 8 mol / L phosphoric acid at a volume ratio of 10:1 and stirred at 40°C for 3 min to break the chelation between lithium ions and the ion exchange system. The lithium ions were transferred to the aqueous phase, resulting in a lithium-rich solution. The lithium concentration of the eluent was 33 g / L, the sodium and potassium concentration was 0.6 ppm, and the product purity was 99.5%.

[0043] Therefore, this invention employs an ion chelation system to solve the problem of selective separation in alkaline high-sodium-potassium solutions due to the high concentration of sodium and potassium and the similar chemical properties of sodium, potassium, and lithium. This system can efficiently and selectively chelate lithium ions, thereby achieving deep separation of lithium from sodium and potassium while significantly improving lithium recovery rate and product purity, and the process is green and environmentally friendly.

[0044] The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described herein. Although the present invention has been described in detail with reference to the above embodiments, the present invention is not limited to the specific embodiments described above. Therefore, any modifications or equivalent substitutions to the present invention, as well as all technical solutions and improvements that do not depart from the spirit and scope of the invention, are covered within the scope of the claims of the present invention.

Claims

1. An ion chelation system for chelation separation of lithium, rubidium and cesium ions from an alkaline high-sodium-potassium solution, characterized by The ion chelation system consists of a chelating agent and a diluent, wherein the diluent is a hydrocarbon compound.

2. The ion chelation system for chelating and separating lithium, rubidium, and cesium ions from an alkaline high-sodium potassium solution according to claim 1, characterized in that, R1COCR2R3COR4, R1CSCR2R3CSR4, R1CSC=CCSR4, R1R2NCS(CH2) n CSNR3R4, wherein R1, R2, R3, R4 are independently selected from H, OH or C1-C 20 one or more of alkanes, alkenes, cycloalkanes, aromatic hydrocarbons.

3. The ion chelation system for chelating and separating lithium, rubidium, and cesium ions from an alkaline high-sodium potassium solution according to claim 1, characterized in that, The hydrocarbon compounds are selected from one or more of alkanes, haloalkanes, aromatics, or cycloalkanes.

4. The ion chelation system for chelating and separating lithium, rubidium, and cesium ions from an alkaline high-sodium potassium solution according to claim 1, characterized in that, The volume ratio of the chelating agent to the diluent is (0.1-10):

1.

5. A method for chelating and separating lithium, rubidium, and cesium ions from an alkaline high-sodium potassium solution, characterized in that, This is achieved by mixing the ion chelation system according to any one of claims 1-4 with an alkaline high-sodium potassium solution and then performing post-treatment. Includes the following steps: S1. Chelation separation: The separation system is mixed with an alkaline high sodium potassium solution for ion chelation, and the ion chelated organic phase containing lithium, rubidium and cesium ions and the sodium potassium aqueous phase after lithium, rubidium and cesium extraction are obtained. S2. Purification and removal of sodium and potassium: Use a purifying agent to purify the ion-chelating organic phase that chelates lithium, rubidium, and cesium ions, and separate the purified ion-chelating organic phase and the sodium and potassium-containing purification solution. S3. Lithium-rubidium-cesium extraction: The purified ion-chelating organic phase is mixed with the chelating agent to carry out the chelation reaction, which breaks the chelation between lithium-rubidium-cesium ions and the chelating agent, and separates the lithium-rich rubidium-cesium solution and the chelating agent after chelation.

6. The separation method for chelating and separating lithium, rubidium, and cesium ions from an alkaline high-sodium potassium solution according to claim 5, characterized in that, In step S1, the concentration of lithium, rubidium, and cesium in the alkaline high-sodium potassium solution is ≤20 g / L, the concentration of sodium and potassium is ≤100 g / L, and the pH is 10-14.

7. The separation method for chelating and separating lithium, rubidium, and cesium ions from an alkaline high-sodium potassium solution according to claim 5, characterized in that, In step S1, the volume ratio of the ion-chelated organic phase to the alkaline high-sodium potassium solution is 1:10-10:

1. In step S2, the volume ratio of the ion-chelated organic phase to the purifying agent is (2-99):1; In step S3, the volume ratio of the purified ion-chelating organic phase to the eluent is (2-20):

1.

8. The separation method for chelating and separating lithium, rubidium, and cesium ions from an alkaline high-sodium potassium solution according to claim 5, characterized in that, The purifying agent in step S2 is one or more of the following: lithium chloride (rubidium cesium), lithium sulfate (rubidium cesium), lithium dihydrogen phosphate (rubidium cesium), lithium phosphate (rubidium cesium), lithium monohydrogen phosphate (rubidium cesium), hydrochloric acid, sulfuric acid, and phosphoric acid.

9. The separation method for chelating and separating lithium, rubidium, and cesium ions from an alkaline high-sodium potassium solution according to claim 5, characterized in that, In step S3, the eluent is hydrochloric acid, sulfuric acid, or phosphoric acid, and the concentration of the eluent acid is 0.1-6 mol / L.

10. The separation method for chelating and separating lithium, rubidium, and cesium ions from an alkaline high-sodium potassium solution according to claim 5, characterized in that, In steps 1 through 3, the chelation, purification, and desorption temperatures are 40-80℃.

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