Method for recovering lithium in lithium precipitation mother liquor

Abstract

The invention provides a method for recovering lithium in lithium precipitation mother liquor, which belongs to the technical field of hydrometallurgy and comprises the following steps: (1) activating a titanium adsorbent: activating the titanium adsorbent by using an acid solution; (2) adsorption: adsorbing lithium in the lithium precipitation mother liquor by using an extruded titanium adsorbent; (3) material washing: washing the adsorbent after adsorption by using pure water; (4) analysis: carrying out circulating analysis on the washed adsorbent by using hydrochloric acid with corresponding concentration to obtain a lithium-rich analysis solution; and (5) refluxing the lithium-containing desorption solution to the lithium precipitation unit. The extruded adsorbent used in the invention has high adsorption capacity and good ion selectivity, and by using the method, the high lithium recovery rate can be ensured, the interference of carnallite ions on lithium recovery can be avoided, the energy consumption is low, and the reduction of the operation cost is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgy, and in particular to a method for recovering lithium from lithium precipitation mother liquor. Background Art

[0002] Lithium mainly includes two natural mineral resources, lithium ore and lithium brine, involving multiple fields such as batteries, ceramics, glass, lubricants, refrigerants, nuclear industry, and optoelectronics. With the vigorous development of the new energy vehicle industry, the demand for lithium resources has surged accordingly. Lithium carbonate is one of the main raw materials for the current production of lithium-ion batteries. Lithium-rich liquid is mainly obtained by sodium carbonate precipitation to obtain lithium carbonate products and lithium precipitation mother liquor. The lithium precipitation mother liquor is a complex multi-component brine system in which the lithium concentration is relatively high (1.3-1.9 g / L) and contains a large amount of Na + (51~65g / L), CO3 2- (35~39g / L), K + (2~5g / L), B, SO4 2- A small amount of trace impurity ions, such as ions in the solution, the pH value of the solution is between 9 and 13. If the lithium precipitation mother liquor is directly returned to the circulation system, long-term use will cause B and Na in the system. + 、CO3 2- Enrichment of trace impurity ions.

[0003] The traditional method of lithium recovery from lithium precipitation mother liquor is to acidify the lithium precipitation mother liquor with sulfuric acid to generate a low-concentration mixed solution of lithium sulfate and sodium sulfate, then evaporate, concentrate and crystallize the acidified solution to separate most of the sodium sulfate, and finally add sodium carbonate solution to the lithium-enriched evaporated crystallization mother liquor to precipitate lithium carbonate. However, due to the large number of impurity salt ions in the lithium precipitation mother liquor, the quality of the obtained lithium carbonate is not high, and only industrial-grade lithium carbonate can be produced, with small product output, low selling price and high production cost.

[0004] The Chinese invention patent application with publication number CN106882822A discloses a method for recovering lithium from lithium precipitation mother liquor into battery-grade lithium carbonate. The lithium precipitation mother liquor produced when lithium sulfate is used as a raw material to react with sodium carbonate to produce lithium carbonate is frozen and salted out to separate sodium sulfate decahydrate solid; the mixed liquor of lithium carbonate and sodium sulfate is then finely filtered and evaporated to concentrate the lithium precipitation to obtain crude lithium carbonate and concentrated mother liquor; the crude lithium carbonate is washed and dried with fine filtrate and pure water to obtain high-purity battery-grade lithium carbonate; the concentrated mother liquor is returned to the freezing and salting out step, and the washing liquid is returned to the fine filtrate. However, the lithium extraction rate of this technology is relatively low, the consumption of freezing and cooling, evaporation, etc. is large, and the production cost is high.

[0005] The Chinese patent application with publication number CN118957303A provides a method for extracting lithium from lithium precipitation mother liquor in salt lakes, wherein sodium chloride salt (byproduct) is prepared into sodium chloride salt solution, calcium, magnesium and other salt ions in the sodium chloride solution are removed by resin, and hydrochloric acid solution and sodium hydroxide solution are obtained after electrolysis; the lithium-containing solution is pretreated with pH adjustment by sodium hydroxide solution, lithium ions are extracted from the pretreated lithium-containing solution, and then back-extracted with hydrochloric acid, and the lithium chloride back-extracted solution is treated with lithium precipitation to obtain lithium carbonate product and lithium precipitation waste liquid; the lithium precipitation waste liquid is treated with nanofiltration to obtain sodium carbonate filtrate and chloride salt filtrate. However, organic solvents are used in the extraction process, which may cause environmental pollution and have high requirements for equipment; in addition to extraction, adsorption and membrane separation processes are also included, and the process is relatively complicated.

[0006] How to improve the recovery rate of lithium in lithium precipitation mother liquor, reduce the impurity content in lithium recovery liquid, reduce energy consumption, green production, reduce costs and increase efficiency, these are the problems that need to be solved in the existing technology. Summary of the invention

[0007] The object of the present invention is to provide a method for recovering lithium from lithium precipitation mother liquor to solve at least one technical problem existing in the above-mentioned background technology.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] The present invention provides a method for recovering lithium from a lithium precipitation mother liquor, comprising the following steps:

[0010] Preparation of titanium-based adsorbent: preparing titanium-based lithium ion sieve precursor β-Li2TiO3, and then mixing the powdered lithium ion sieve precursor with a dispersant and a cross-linking agent to prepare an extruded titanium-based adsorbent;

[0011] The titanium-based adsorbent is loaded into an adsorption column, activated with an acid solution, and then introduced into a lithium precipitation mother solution for adsorption, with an adsorption lithium yield greater than 97%;

[0012] The titanium-based adsorbent after adsorption is washed with water to remove the salt ions attached to the surface of the adsorbent; the washing liquid is returned to the original brine for lithium recovery;

[0013] An acid solution is introduced to analyze the washed adsorbent to obtain a lithium-rich qualified solution; the lithium-rich qualified solution is refluxed to the lithium precipitation unit for reuse;

[0014] The titanium-based adsorbent after analysis is washed with water to remove hydrogen ions and lithium ions on the surface of the adsorbent.

[0015] Furthermore, the lithium precipitation mother liquor is lithium carbonate lithium precipitation mother liquor.

[0016] Furthermore, the adsorption temperature of the lithium precipitation mother solution for adsorption is 20-90°C.

[0017] Furthermore, the adsorption temperature is 40-60°C.

[0018] Furthermore, pure water is used for washing.

[0019] Furthermore, the acid used in the acid solution is sulfuric acid or hydrochloric acid, or a mixture of the two.

[0020] Furthermore, the concentration of the acid solution is 0.05 to 0.5 mol / l.

[0021] Furthermore, the concentration of the acid solution is 0.08 to 0.15 mol / L.

[0022] Furthermore, it is necessary to add an acid supplement to maintain the pH of the analytical solution.

[0023] Furthermore, the concentration of the acid supplement solution is 1 to 6 mol / L.

[0024] Furthermore, the decomposition temperature is 20-60°C.

[0025] Furthermore, the decomposition temperature is 40°C.

[0026] Furthermore, the flow rate of the adsorption section is 0.1 to 4 BV / h, and the flow rate of the desorption section is 10 to 30 BV / h.

[0027] Furthermore, the water washing acid solution is returned to the system as part of the analytical water.

[0028] Furthermore, the titanium-based adsorbent after being rinsed in the water-washing and acid-washing stage can be continuously recycled.

[0029] The beneficial effects of the present invention are as follows: the prepared titanium-based lithium ion sieve precursor β-Li2TiO3 has a narrow particle size distribution and a small particle size. The synthesis method is simple to operate, has good repeatability, and is low in cost. The extruded adsorbent used has a large specific surface area, a fast adsorption rate, a high adsorption capacity, and good selectivity. It can be regenerated with acid and recycled. The lithium in the lithium precipitation mother liquor is recovered by adsorption, and the adsorption lithium yield can reach 99%, and the lithium recovery rate is more than 90%, thereby avoiding the lithium loss caused by salt crystallization in the traditional process. The lithium purity in the analyzed qualified liquid is high, and the lithium-sodium ratio is greater than 2. The qualified liquid can be directly refluxed to the lithium precipitation unit to produce battery-grade lithium carbonate, which solves the problems of high energy consumption such as freezing and evaporation in the prior art, reduces costs, and further increases the production efficiency of the enterprise.

[0030] Additional advantages of the present invention will be more clearly given in the following description or learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0032] Figure 1 This is a flow chart of a method for risk assessment of a highway traffic system under a major emergency event according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below by the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention.

[0034] It should be understood by those skilled in the art that unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which this invention belongs.

[0035] It should also be understood that terms, such as those defined in commonly used dictionaries, should be understood to have a meaning consistent with that in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless as defined herein.

[0036] Those skilled in the art will appreciate that, unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements and / or groups thereof.

[0037] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. Different embodiments or examples described in this specification and features of different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

[0038] To facilitate understanding of the present invention, the present invention is further explained below with reference to specific embodiments in conjunction with the accompanying drawings, and the specific embodiments do not constitute a limitation on the embodiments of the present invention.

[0039] Those skilled in the art should understand that the drawings are merely schematic diagrams of embodiments, and the components in the drawings are not necessarily necessary for implementing the present invention.

[0040] Example 1

[0041] like Figure 1 As shown, in this embodiment 1, a method for recovering lithium from lithium precipitation mother liquor is provided, comprising the following steps:

[0042] Step 1: Preparation of titanium-based adsorbent: Prepare titanium-based lithium ion sieve precursor β-Li2TiO3, then mix the powdered lithium ion sieve precursor with a dispersant, a cross-linking agent, etc., and prepare an extruded titanium-based adsorbent by processing. In this embodiment, the titanium-based lithium ion sieve precursor β-Li2TiO3 is prepared by the method described in the Chinese invention patent application with publication number CN118145699A, which will not be repeated here.

[0043] Step 2: Adsorption: The titanium-based adsorbent is loaded into the adsorption column, activated with an acid solution, and then the lithium precipitation mother liquor is introduced for adsorption. The adsorption lithium yield can reach 99%;

[0044] Step 3: Washing the material with water: Wash the titanium-based adsorbent after adsorption in step (2) with water to remove the salt ions attached to the surface of the adsorbent;

[0045] Step 4: Analysis: Pass an acid solution into the adsorbent in (3) to analyze and obtain a lithium-rich qualified solution;

[0046] Step 5: Acid washing: The titanium-based adsorbent in step (4) is washed with water to remove hydrogen ions and lithium ions on the surface of the adsorbent.

[0047] Step 6: The qualified lithium-rich solution is returned to the lithium sinking unit for reuse.

[0048] The titanium-based lithium ion sieve precursor has a narrow particle size distribution and a small particle size. The synthesis method is simple to operate, has good repeatability, and is low in cost. The titanium-based adsorbent has the advantages of large specific surface area, fast adsorption rate, high adsorption capacity, and good adsorption selectivity, and the adsorption capacity is 2 to 24 mg / g. The lithium precipitation mother liquor is a lithium carbonate lithium precipitation mother liquor, which is one of the sulfate-type or chloride-type salt lake lithium precipitation mother liquors. The pH of the lithium precipitation mother liquor is 10 to 14. High alkalinity is conducive to the replacement of hydrogen on the titanium-based adsorbent with lithium in the lithium precipitation mother liquor, which can provide a stronger driving force for the titanium-based adsorbent to adsorb lithium ions. Preferably, the pH of the lithium precipitation mother liquor of the present invention is greater than 13. The adsorption section flow rate is 0.1 to 4 BV / h, and the decomposition flow rate is 10 to 30 BV / h. The adsorption temperature in the step (2) is 20 to 90°C. Temperature is a key factor in controlling the reaction rate and affecting the adsorption capacity. Higher temperatures will provide lithium ions with more favorable collision opportunities and stronger driving forces, thereby effectively improving the diffusion capacity of ions into the material. However, too high a temperature may affect the structure of the adsorbent and thus affect the adsorption effect. Preferably, the adsorption temperature is selected to be 40 to 60°C. The acid used for activating the adsorbent in step (2) and the acid used for analysis in step (4) is a mixture of one or two acids of sulfuric acid or hydrochloric acid, with a concentration of 0.05 to 0.5 mol / l. Studies have found that as the concentration of hydrogen ions in the analysis liquid increases, the analysis efficiency of lithium ions on the adsorbent can be effectively improved, but the titanium dissolution loss will increase, affecting the service life of the adsorbent. Preferably, the concentration is selected to be 0.08 to 0.15 mol / L. In step (4), an acid supplement is required to maintain the pH of the analysis liquid, and the concentration of the acid supplement is 1 to 6 mol / L. The analysis temperature in step (4) is 20 to 60°C, and preferably, the analysis temperature is 40°C. The rinse water for the washed material in step (3) is pure water, and the water of the washed material can be returned to the original halogen to recover lithium. The water used for water washing and acid rinsing in step (5) is pure water, which is returned to the system as part of the water for analysis, and can not only recover the hydrogen ions in the solution, but also rinse off the lithium on the surface of the adsorbent to avoid affecting the adsorption effect of the next cycle. The titanium-based adsorbent rinsed by the water washing and acid rinsing stage can be continuously recycled.

[0049] Example 2

[0050] In this embodiment, 100 mL of titanium-based adsorbent is loaded into the column, and then the lithium precipitate mother liquor heated to 50°C is passed into the adsorption column filled with activated titanium-based adsorbent (the adsorption column is equipped with an insulation jacket) at a flow rate of 1BV / h for adsorption for 3 to 5 hours. After the lithium precipitate mother liquor is completely discharged from the adsorption column, pure water is passed into it at a flow rate of 4BV / h for washing, and the adsorbed mother liquor and the adsorbed washing water are collected to determine the Li content therein. Subsequently, at 40°C, a volume of 3BV and a concentration of 0.1mol / L of hydrochloric acid are used for cyclic desorption at a flow rate of 20BV / h. During this period, 1 to 6mol / L of hydrochloric acid is added to control the pH at 1 to 1.5 until the pH value of the desorbed liquid remains unchanged. After all the analytical solution is removed from the column, pure water is passed into it at a flow rate of 4BV / h for washing, and the desorbed liquid and the desorbed washing water are collected to determine the Li content therein. According to ICP detection, Li in the adsorbed liquid + The adsorption rate of lithium is 0.015-0.066 g / L, the lithium adsorption yield is 96.5%-99.2%, and the Li + The concentration is 1.4-1.6 g / L, Na + The concentration is 0.54-0.73 g / L. The washed material is returned to the original brine for lithium recovery, and the analytical solution is returned to the lithium precipitation process as a lithium-rich solution for lithium precipitation. According to calculations, the lithium recovery rate is about 91.6-95%.

[0051] Example 3

[0052] In the present embodiment 3, 100mL titanium adsorbent is loaded into the column, and then the lithium precipitate mother liquor heated to 50°C is passed into the adsorption column (the adsorption column is equipped with a heat preservation jacket) filled with the activated titanium adsorbent at a flow rate of 2BV / h, and adsorbed for 3-5h. After the lithium precipitate mother liquor is completely discharged from the adsorption column, pure water is passed into the column at a flow rate of 4BV / h for 30min for washing, and the mother liquor after adsorption and the washing water after adsorption are collected to measure the Li content therein. Subsequently, hydrochloric acid with a volume of 3BV and a concentration of 0.1mol / L is used at a flow rate of 20BV / h for cyclic desorption at 40°C, and the pH is controlled at 1-1.5 by adding 1-6mol / L of hydrochloric acid during the period until the pH value of the desorption liquid remains unchanged. After the analytical solution is completely excluded from the column, pure water is passed into the column at a flow rate of 4BV / h for 30min for washing, and the desorption liquid and the washing water after desorption are collected to measure the Li content therein. ICP detection showed that the Li + The adsorption rate of lithium is 0.054-0.111 g / L, the yield of lithium adsorption is 94.1%-97.4%, and the Li + The concentration is 1.4-1.6 g / L, Na + The concentration is 0.57-0.75 g / L. The washed material is returned to the original brine for lithium recovery, and the analytical solution is returned to the lithium precipitation process as a lithium-rich solution for lithium precipitation. According to calculations, the lithium recovery rate is about 90-93%.

[0053] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative work on the basis of the technical solution disclosed in the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for recovering lithium from lithium precipitation mother liquor, characterized in that: The following steps are involved: Preparation of titanium-based adsorbent: preparing titanium-based lithium ion sieve precursor β-Li2TiO3, and then mixing the powdered lithium ion sieve precursor with a dispersant and a cross-linking agent to prepare an extruded titanium-based adsorbent; The titanium-based adsorbent is loaded into an adsorption column, activated with an acid solution, and then introduced into a lithium precipitation mother solution for adsorption, with an adsorption lithium yield greater than 97%; The titanium-based adsorbent after adsorption is washed with water to remove the salt ions attached to the surface of the adsorbent; the washing liquid is returned to the original brine for lithium recovery; Passing an acid solution into the washed adsorbent to analyze it and obtain a lithium-rich qualified solution; The qualified lithium-rich solution is returned to the lithium sinking unit for reuse; The titanium-based adsorbent after analysis is washed with water to remove hydrogen ions and lithium ions on the surface of the adsorbent.

2. The method for recovering lithium from lithium precipitation mother liquor according to claim 1, characterized in that: The lithium precipitation mother liquor is lithium carbonate lithium precipitation mother liquor.

3. The method for recovering lithium from lithium precipitation mother liquor according to claim 1, characterized in that: The adsorption temperature of the lithium precipitation mother solution is 20-90°C.

4. The method for recovering lithium from lithium precipitation mother liquor according to claim 3, characterized in that: The adsorption temperature is 40-60°C.

5. The method for recovering lithium from lithium precipitation mother liquor according to claim 1, characterized in that: Use pure water for washing.

6. The method for recovering lithium from lithium precipitation mother liquor according to claim 1, characterized in that: The acid used in the acid solution is sulfuric acid or hydrochloric acid or a mixture of the two.

7. The method for recovering lithium from lithium precipitation mother liquor according to claim 6, characterized in that: The concentration of the acid solution is 0.05-0.5 mol / l.

8. The method for recovering lithium from lithium precipitation mother liquor according to claim 7, characterized in that: The concentration of the acid solution is 0.08-0.15 mol / L.

9. The method for recovering lithium from lithium precipitation mother liquor according to claim 1, characterized in that: The decomposition temperature is 20-60°C.

10. The method for recovering lithium from lithium precipitation mother liquor according to claim 9, characterized in that: The decomposition temperature is 40°C.

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