Method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate

Abstract

Disclosed in the present invention is a method for extracting and separating lithium from a lithium precipitation mother liquor and preparing battery-grade lithium carbonate. The method comprises: mixing an extractant with a lithium precipitation mother liquor for extraction to obtain a raffinate and a lithium-loaded organic phase; mixing the lithium-loaded organic phase with an acid solution for washing; mixing the washed lithium-loaded organic phase with an acid solution of a certain concentration for stripping; returning a blank organic phase for re-extraction; mixing a lithium-rich solution with a soda ash solution of a certain concentration for lithium precipitation; returning the lithium precipitation mother liquor for re-extraction; and drying and crushing wet lithium carbonate to obtain a battery-grade lithium carbonate finished product. In the present application, the lithium precipitation mother liquor is used as a raw material, and is directly mixed with the extractant for extraction without alkali adjustment, thereby avoiding the need to supplement alkalinity by supplementing sodium salt or potassium salt in a traditional lithium extraction process, and reducing the amount of metal ions in a water sample. In addition, there is no need to perform a concentration step on the lithium precipitation mother liquor, thereby reducing energy consumption and production costs, and the extraction rate and direct recovery rate of lithium are relatively high.

Description

A method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate. Technical Field

[0001] This invention relates to the field of hydrometallurgy, and more particularly to a method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate. Background Technology

[0002] Currently, methods for extracting lithium from lithium precipitation mother liquor include concentration precipitation, resin adsorption, and solvent extraction.

[0003] CN201110122564.9 discloses a method for concentration and precipitation: after neutralizing carbon with acid, the lithium precipitation mother liquor is evaporated and concentrated to separate and precipitate sodium salt, which is then returned to the lithium precipitation section for recycling. This method is currently widely used in industrial production; however, it is energy-intensive, and impurities tend to accumulate during the recycling of the mother liquor, resulting in mostly industrial-grade lithium carbonate, which requires further purification at a high cost.

[0004] CN202311603408.3 discloses a method for preparing titanium-based adsorbents and extracting lithium: lithium ions are extracted from brine using an adsorbent with selective lithium ion adsorption properties, followed by desorption and enrichment of the lithium ions with an acidic solution, and then lithium carbonate is prepared by precipitation. However, this method has high adsorbent preparation costs, complex processes, large equipment investment costs, and a high adsorbent wear rate. Therefore, solvent extraction is a more economical and practical method for extracting lithium from the mother liquor of lithium precipitation.

[0005] CN202110753234.3 discloses a method for lithium extraction; however, its main application scenarios are acidic brine in salt lakes and carbonate and chloride salt systems, with little research on lithium precipitation mother liquor from sulfate systems prepared by ore method.

[0006] CN202211589226.0 also discloses a lithium extraction method. However, it requires the addition of alkaline solutions such as sodium hydroxide during the extraction process, and the extraction effect is not particularly outstanding. The raffinate also contains 50 mg / L of unused lithium ions. Technical issues

[0007] Therefore, in view of the problems existing in the prior art, the present invention aims to provide a method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate with low energy consumption and high lithium recovery rate without the need for alkali. Technical solutions

[0008] The main objective of this invention is to provide a method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate, aiming to improve the method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate without the need for alkali consumption, with low energy consumption and high lithium recovery rate.

[0009] To achieve the above objectives, the present invention proposes a method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate, comprising:

[0010] S1. The extractant is thoroughly mixed with the lithium precipitation mother liquor to obtain the raffinate and the lithium-loaded organic phase.

[0011] S2. Wash the lithium-supported organic phase obtained in step S1 with pure water or acid solution.

[0012] S3. The cleaned lithium-supported organic phase obtained in step S2 is mixed with an acid solution of a certain concentration for back-extraction.

[0013] S4. Return the blank organic phase obtained in step S3 to step S1 for extraction again; mix the lithium-rich solution with a certain concentration of soda ash solution to precipitate lithium.

[0014] S5. Return the lithium precipitation mother liquor obtained in step S4 to step S1 for re-extraction; dry and crush the wet lithium carbonate to obtain battery-grade lithium carbonate product.

[0015] In one embodiment, the pH of the lithium precipitation mother liquor solution in step S1 is 10-13.5.

[0016] In one embodiment, the extractant in step S1 includes one or more of 2-thiophenecarboxyltrifluoroacetone, octylbenzoylmethane, dibenzoylmethane, hypozoxytriacetic acid, benzoyltrifluoroacetone, trifluorotoluene diacetone, 2-furanoyltrifluoroacetone, tributyl phosphate, trialkylphosphine oxide, 2-ethylhexylphosphine, and trioctylphosphine oxide.

[0017] In one embodiment, a diluent is added in step S1, wherein the diluent is one or more of sulfonated kerosene, D100 solvent oil, D70 solvent oil, n-dodecane, propanol, and butanol.

[0018] In one embodiment, the OA ratio of the extractant to the lithium precipitation mother liquor in step S1 is 1:1-5:1.

[0019] In one embodiment, the washing ratio in step S2 is 1:1 to 30:1.

[0020] In one embodiment, the washing liquid in step S2 can be pure water or at least one of hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid with a hydrogen ion concentration of 0.01 mol / L to 0.5 mol / L.

[0021] In one embodiment, the acid solution used in step S3 is at least one of hydrochloric acid, sulfuric acid, nitric acid, and hydrofluoric acid with a hydrogen ion concentration of 0.5 mol / L to 8 mol / L.

[0022] In one embodiment, the concentration of the soda ash solution in step S4 is 1 mol / L to 4 mol / L.

[0023] In one embodiment, the drying temperature in step S5 is 200℃-700℃.

[0024] In the technical solution of this invention, the method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate includes:

[0025] S1. The extractant is thoroughly mixed with the lithium precipitation mother liquor to obtain the raffinate and the lithium-loaded organic phase.

[0026] S2. Wash the lithium-supported organic phase obtained in step S1 with pure water or acid solution.

[0027] S3. The cleaned lithium-supported organic phase obtained in step S2 is mixed with an acid solution of a certain concentration for back-extraction.

[0028] S4. Return the blank organic phase obtained in step S3 to step S1 for extraction again; mix the lithium-rich solution with a certain concentration of soda ash solution to precipitate lithium.

[0029] S5. Return the lithium precipitation mother liquor obtained in step S4 to step S1 for re-extraction; dry and crush the wet lithium carbonate to obtain battery-grade lithium carbonate product. Beneficial effects

[0030] This invention uses lithium precipitation mother liquor as raw material, and directly mixes it with the extractant for extraction without adjusting the alkali. This avoids the need to supplement sodium or potassium salts to increase alkalinity in the traditional lithium extraction process, and reduces the increase of metal ions in the water sample. At the same time, there is no need to concentrate the lithium precipitation mother liquor, which reduces energy consumption and production costs. In addition, the lithium extraction rate and direct recovery rate are relatively high.

[0031] The lithium carbonate prepared by this invention has high purity, especially by reducing the proportion of potassium and sodium salts in the lithium carbonate product, thus meeting the battery-grade lithium carbonate standard. This solves the problems of complex purification processes and high production costs associated with traditional concentrated lithium precipitation for preparing industrial-grade lithium carbonate.

[0032] The lithium precipitation mother liquor generated during the preparation of lithium carbonate in this invention is returned to the extraction section, realizing the complete utilization of the residual lithium resources in the lithium precipitation mother liquor. At the same time, no waste is generated during the production process, thus avoiding environmental pollution. Attached Figure Description

[0033] 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 of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0034] Figure 1 is a process flow diagram of the method for extracting and separating lithium from lithium mother liquor and preparing battery-grade lithium carbonate according to an embodiment of the present invention.

[0035] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Embodiments of the present invention

[0036] 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 only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0037] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0038] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0039] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0040] This invention provides a method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate.

[0041] As shown in Figure 1, the method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate provided in this embodiment of the invention includes:

[0042] S1. The extractant is thoroughly mixed with the lithium precipitation mother liquor to obtain the raffinate and the lithium-loaded organic phase.

[0043] S2. Wash the lithium-supported organic phase obtained in step S1 with pure water or acid solution.

[0044] S3. The cleaned lithium-supported organic phase obtained in step S2 is mixed with an acid solution of a certain concentration for back-extraction.

[0045] S4. Return the blank organic phase obtained in step S3 to step S1 for extraction again; mix the lithium-rich solution with a certain concentration of soda ash solution to precipitate lithium.

[0046] S5. Return the lithium precipitation mother liquor obtained in step S4 to step S1 for re-extraction; dry and crush the wet lithium carbonate to obtain battery-grade lithium carbonate product.

[0047] In one embodiment, the pH of the lithium precipitation mother liquor solution in step S1 is 10-13.5.

[0048] In one embodiment, the extractant in step S1 includes one or more of 2-thiophenecarboxyltrifluoroacetone, octylbenzoylmethane, dibenzoylmethane, hypozoxytriacetic acid, benzoyltrifluoroacetone, trifluorotoluene diacetone, 2-furanoyltrifluoroacetone, tributyl phosphate, trialkylphosphine oxide, 2-ethylhexylphosphine, and trioctylphosphine oxide.

[0049] In one embodiment, a diluent is added in step S1, wherein the diluent is one or more of sulfonated kerosene, D100 solvent oil, D70 solvent oil, n-dodecane, propanol, and butanol.

[0050] In one embodiment, the OA ratio of the extractant to the lithium precipitation mother liquor in step S1 is 1:1-5:1.

[0051] In one embodiment, the washing ratio in step S2 is 1:1 to 30:1.

[0052] In one embodiment, the washing liquid in step S2 can be pure water or at least one of hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid with a hydrogen ion concentration of 0.01 mol / L to 0.5 mol / L.

[0053] In one embodiment, the acid solution used in step S3 is at least one of hydrochloric acid, sulfuric acid, nitric acid, and hydrofluoric acid with a hydrogen ion concentration of 0.5 mol / L to 8 mol / L.

[0054] In one embodiment, the concentration of the soda ash solution in step S4 is 1 mol / L to 4 mol / L.

[0055] In one embodiment, the drying temperature in step S5 is 200℃-700℃.

[0056] In this application, the lithium content of the lithium precipitation mother liquor in step S1 is 1.8 g / L-3 g / L. The calcium content of the lithium precipitation mother liquor in step S1 is 1-10 mg / L.

[0057] In step S3, the pH of the mixing chamber can be controlled between 0 and 6 to ensure that the back-extraction process is fully carried out.

[0058] The present application will be explained below through various specific embodiments. Example 1

[0059] A method for extracting and separating lithium from lithium precipitate mother liquor and preparing battery-grade lithium carbonate, the process flow is shown in Figure 1, and is carried out according to the following steps: Step S1, the lithium precipitate mother liquor and the extractant are thoroughly mixed in a mixing chamber, the ratio of extractant to lithium precipitate mother liquor is 2:1, and three mixing and clarification chambers are used. After three countercurrent extractions, a lithium-loaded organic phase and raffinate are obtained, and the pH of the extraction chamber is measured to be 7.6. Step S2, a certain amount of pure water is used to wash the lithium-loaded organic phase, the washing ratio is 10:1, and the washing is also carried out in three mixing and clarification chambers. The wash water is returned to the mixing chamber in step S1 for re-extraction. Step S3, a 3 mol / L sulfuric acid solution is used to thoroughly mix the lithium-loaded organic phase with the precipitate mother liquor in a mixing chamber, the ratio of sulfuric acid solution to lithium-loaded organic phase is 20:1, and two countercurrent back-extractions are used to obtain a blank organic phase and a lithium-rich solution product. The pH of the mixing chamber is monitored to be 3.98. Step S4: Add 1.5 mol / L soda ash solution according to the lithium content of the lithium-rich solution, maintain the reaction temperature at 95 degrees Celsius, and after the addition is complete, continue stirring and reacting for 1 hour, then filter to obtain lithium precipitation mother liquor and wet lithium carbonate. Step S5: Return the lithium precipitation mother liquor obtained in step S4 to the mixing and stirring chamber in S1 for lithium recycling. After drying and crushing the wet lithium carbonate, battery-grade lithium carbonate product is obtained.

[0060] In step S1, the lithium content of the lithium precipitation mother liquor was 2782 mg / L and the calcium ion content was 4.2 mg / L. The obtained raffinate was analyzed by ICP (inductively coupled plasma mass spectrometry), and the lithium ion content of the raffinate was 7 mg / L, with an extraction rate of 99.7%. Gas chromatography analysis showed that the oil content in the aqueous phase was 4 mg / L.

[0061] In step S3, the lithium-rich solution has a lithium ion content of 27.2 g / L, a back-extraction rate of 97.7%, and an extraction yield of 97.4%.

[0062] After drying at 260℃ in step S5, the composition of the lithium carbonate product obtained by crushing is shown in Table 1 below. Table 1 shows the main components and impurities of lithium carbonate (unit: %).

[0063]

[0064] Table 1 Example 2

[0065] A method for extracting and separating lithium from lithium precipitate mother liquor and preparing battery-grade lithium carbonate, the process flow is shown in Figure 1, and is carried out according to the following steps: Step S1, the lithium precipitate mother liquor and the extractant are thoroughly mixed in a mixing chamber, the ratio of extractant to lithium precipitate mother liquor is 3:1, and three mixing and clarification chambers are used. After three countercurrent extractions, a lithium-loaded organic phase and raffinate are obtained, and the pH of the extraction chamber is measured to be 7.2. Step S2, a certain amount of pure water is used to wash the lithium-loaded organic phase, the washing ratio is 15:1, and the washing is also carried out in three mixing and clarification chambers. The wash water is returned to the mixing chamber in step S1 for re-extraction. Step S3, a 2 mol / L sulfuric acid solution is used to thoroughly mix the lithium-loaded organic phase with the 2 mol / L sulfuric acid solution in a mixing chamber, the ratio of sulfuric acid solution to lithium-loaded organic phase is 15:1, and two countercurrent back-extractions are used to obtain a blank organic phase and a lithium-rich solution product. The pH of the mixing chamber is monitored to be 4.12. Step S4: Add 1 mol / L soda ash solution according to the lithium content of the lithium-rich solution, maintain the reaction temperature at 95 degrees Celsius, and after the addition is complete, continue stirring and reacting for 1 hour, then filter to obtain lithium precipitation mother liquor and wet lithium carbonate. Step S5: Return the lithium precipitation mother liquor obtained in step S4 to the mixing and stirring chamber in S1 for lithium extraction. After drying and crushing the wet lithium carbonate, battery-grade lithium carbonate product is obtained.

[0066] In step S1, the lithium content of the lithium precipitation mother liquor was 2804 mg / L and the calcium ion content was 8.4 mg / L. The obtained raffinate was analyzed by ICP (inductively coupled plasma mass spectrometry), and the lithium ion content of the raffinate was 6 mg / L, with an extraction rate of 99.7%. Gas chromatography analysis showed that the oil content in the aqueous phase was 8 mg / L.

[0067] In step S3, the lithium-rich solution has a lithium ion content of 13.6 g / L, a back-extraction rate of 97.3%, and an extraction yield of 97.0%.

[0068] In step S5, after drying at 300℃, the composition of the lithium carbonate product obtained by crushing is shown in Table 2 below. Table 2 shows the main components and impurities of lithium carbonate (unit %).

[0069]

[0070] Table 2 Example 3

[0071] A method for extracting and separating lithium from lithium precipitate mother liquor and preparing battery-grade lithium carbonate, the process flow is shown in Figure 1, and is carried out according to the following steps: Step S1, the lithium precipitate mother liquor and the extractant are thoroughly mixed in a mixing chamber, the ratio of extractant to lithium precipitate mother liquor is 1.5:1, and three mixing and clarifying chambers are used. After three countercurrent extractions, a lithium-loaded organic phase and raffinate are obtained, and the pH of the extraction chamber is measured to be 7.7. Step S2, a certain amount of 0.05 mol / L hydrochloric acid solution is used to wash the lithium-loaded organic phase, the washing ratio is 10:1, and three mixing and clarifying chambers are used for washing. The wash water is returned to the mixing chamber in step S1 for re-extraction. Step S3, a 5 mol / L hydrochloric acid solution is used to thoroughly mix the lithium-loaded organic phase in a mixing chamber, the ratio of hydrochloric acid solution to lithium-loaded organic phase is 15:1, and two countercurrent back-extractions are used to obtain a blank organic phase and a lithium-rich solution product. The pH of the mixing chamber is monitored to be 4.32. Step S4: Add 2 mol / L soda ash solution according to the lithium content of the lithium-rich solution, maintain the reaction temperature at 95 degrees Celsius, and after the addition is complete, continue stirring the reaction for 1.5 hours, then filter to obtain lithium precipitation mother liquor and wet lithium carbonate. Step S5: Return the lithium precipitation mother liquor obtained in step S4 to the mixing and stirring chamber in S1 for lithium extraction. After drying and crushing the wet lithium carbonate, battery-grade lithium carbonate product is obtained.

[0072] In step S1, the lithium content of the lithium precipitation mother liquor was 2886 mg / L and the calcium ion content was 3.6 mg / L. The obtained raffinate was analyzed by ICP (inductively coupled plasma mass spectrometry), and the lithium ion content of the raffinate was 11 mg / L, with an extraction rate of 99.6%. Gas chromatography analysis showed that the oil content in the aqueous phase was 5 mg / L.

[0073] In step S3, the lithium-rich solution has a lithium ion content of 27.7 g / L, a back-extraction rate of 96.1%, and an extraction yield of 95.7%.

[0074] In step S5, after drying at 400℃, the lithium carbonate product obtained by crushing meets the battery-grade lithium carbonate standard. Its composition is shown in Table 3 below. Table 3 shows the main components and impurities of lithium carbonate (unit %).

[0075]

[0076] Table 3

[0077] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made under the concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate, characterized in that, The method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate includes: S1. The extractant is thoroughly mixed with the lithium precipitation mother liquor to obtain the raffinate and the lithium-loaded organic phase. S2. Wash the lithium-supported organic phase obtained in step S1 with pure water or acid solution. S3. The cleaned lithium-supported organic phase obtained in step S2 is mixed with an acid solution of a certain concentration for back-extraction. S4. Return the blank organic phase obtained in step S3 to step S1 for extraction again; mix the lithium-rich solution with a certain concentration of soda ash solution to precipitate lithium. S5. Return the lithium precipitation mother liquor obtained in step S4 to step S1 for re-extraction; dry and crush the wet lithium carbonate to obtain battery-grade lithium carbonate product.

2. The method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate according to claim 1, characterized in that, The pH of the lithium precipitation mother liquor solution in step S1 is 10-13.

5.

3. The method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate according to claim 1, characterized in that, The extractant in step S1 includes one or more of 2-thiophenecarboxyltrifluoroacetone, octylbenzoylmethane, dibenzoylmethane, hypozoxytriacetic acid, benzoyltrifluoroacetone, trifluorotoluene diacetone, 2-furanoyltrifluoroacetone, tributyl phosphate, trialkylphosphine oxide, 2-ethylhexylphosphine, and trioctylphosphine oxide.

4. The method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate according to claim 1, characterized in that, In step S1, a diluent is added, which is one or more of sulfonated kerosene, D100 solvent oil, D70 solvent oil, n-dodecane, propanol, and butanol.

5. The method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate according to claim 1, characterized in that, In step S1, the OA ratio of the extractant to the lithium precipitation mother liquor is 1:1-5:

1.

6. The method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate according to claim 1, characterized in that, In step S2, the washing ratio is 1:1 to 30:

1.

7. The method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate according to claim 1, characterized in that, The washing liquid in step S2 can be pure water or at least one of hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid with a hydrogen ion concentration of 0.01 mol / L to 0.5 mol / L.

8. The method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate according to claim 1, characterized in that, The acid solution used in step S3 is at least one of hydrochloric acid, sulfuric acid, nitric acid, and hydrofluoric acid with a hydrogen ion concentration of 0.5 mol / L to 8 mol / L.

9. The method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate according to claim 1, characterized in that, In step S4, the concentration of the soda ash solution is 1 mol / L to 4 mol / L.

10. The method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate according to claim 1, characterized in that, The drying temperature in step S5 is 200℃-700℃.

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