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

Abstract

The invention discloses a method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate. The method comprises the following steps: mixing and extracting an extracting agent and the lithium precipitation mother liquor to obtain raffinate and a lithium-loaded organic phase; mixing the lithium-loaded organic phase with an acid solution, and washing; mixing the washed lithium-loaded organic phase with an acid solution with a certain concentration for reverse extraction; returning the blank organic phase for re-extraction; mixing the lithium-rich solution with a sodium carbonate solution with a certain concentration for lithium precipitation; the lithium precipitation mother liquor is returned for re-extraction; and drying and crushing the wet lithium carbonate to obtain a battery-grade lithium carbonate finished product. The lithium precipitation mother liquor is taken as a raw material and is directly mixed with the extraction agent for extraction without alkali adjustment, so that the problem that sodium salt or potassium salt needs to be supplemented for alkalinity in the traditional lithium extraction process is avoided, and the increase of metal ions in a water sample is reduced; meanwhile, the step of concentrating the lithium precipitation mother liquor is not needed, so that the energy consumption and the production cost are reduced, and meanwhile, the extraction rate and the direct recovery rate of lithium are relatively high.

Description

Technical Field

[0001] The invention relates to the field of hydrometallurgy, and in particular to a method for extracting and separating lithium from lithium precipitation mother liquor and preparing battery-grade lithium carbonate. Background Art

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

[0003] Among them, CN201110122564.9 discloses a method of concentration and precipitation: the lithium precipitation mother liquor is neutralized and decarbonized by acid, evaporated and concentrated, sodium salt is separated and precipitated, and then returned to the lithium precipitation section for recycling. This method is currently mostly used in industrial production; however, this method consumes a lot of energy, and impurities are easily enriched during the recycling of the mother liquor. The prepared lithium carbonate is mostly industrial grade lithium carbonate, and the cost of further purification is relatively high.

[0004] CN202311603408.3 discloses a method for preparing a titanium-based adsorbent and extracting lithium: using an adsorbent with selective adsorption of lithium ions to extract lithium ions from brine, then using an acidic solution to desorb and enrich the lithium ions, and then precipitating lithium to prepare lithium carbonate. However, the adsorbent preparation cost of this method is high, the process is relatively complicated, the equipment investment cost is large, and the adsorbent wear rate is also high. Therefore, it is more economical to extract lithium from the lithium precipitation mother liquor using a solvent extraction method.

[0005] CN202110753234.3 discloses a lithium extraction method, however, its main application scenarios are salt lake acidic brine and carbonate and chloride salt systems, and there is little research on lithium precipitation mother liquor in the sulfate system prepared by the ore method.

[0006] CN202211589226.0 also discloses a lithium extraction method, however, it requires additional supplementation 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 residual unutilized lithium ions.

[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 precipitate mother liquor and preparing battery-grade lithium carbonate, which does not require alkali consumption, has low energy consumption and high lithium recovery rate. Summary of the invention

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

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

[0010] S1, fully mixing the extractant with the lithium precipitation mother liquor to obtain a raffinate and a lithium-loaded organic phase;

[0011] S2, mixing the lithium-loaded organic phase obtained in step S1 with pure water or acid solution for washing;

[0012] S3, mixing the washed lithium-loaded organic phase obtained in step S2 with an acid solution of a certain concentration for stripping;

[0013] S4, returning the blank organic phase obtained in step S3 to step S1 for re-extraction; mixing the lithium-rich solution with a certain concentration of soda ash solution to precipitate lithium;

[0014] S5, returning the lithium precipitation mother liquor obtained in step S4 to step S1 for re-extraction; drying and crushing the wet lithium carbonate to obtain a battery-grade lithium carbonate product.

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

[0016] In one embodiment, the extractant in step S1 includes one or more of 2-thenoyltrifluoroacetone, octylbenzoylmethane, dibenzoylmethane, nitrilotriacetic acid, benzoyltrifluoroacetone, trifluorotoluene diacetate, 2-furoyltrifluoroacetone, tributyl phosphate, trialkylphosphine oxide, 2-ethylhexyl phosphoric acid, and trioctylphosphine oxide.

[0017] In one embodiment, a diluent is added in step S1, and 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 phase ratio in step S2 is 1:1-30:1.

[0020] In one embodiment, the washing liquid in step S2 may 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-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-8 mol / L.

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

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

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

[0025] S1, fully mixing the extractant with the lithium precipitation mother liquor to obtain a raffinate and a lithium-loaded organic phase;

[0026] S2, mixing the lithium-loaded organic phase obtained in step S1 with pure water or acid solution for washing;

[0027] S3, mixing the washed lithium-loaded organic phase obtained in step S2 with an acid solution of a certain concentration for stripping;

[0028] S4, returning the blank organic phase obtained in step S3 to step S1 for re-extraction; mixing the lithium-rich solution with a certain concentration of soda ash solution to precipitate lithium;

[0029] S5, returning the lithium precipitation mother liquor obtained in step S4 to step S1 for re-extraction; drying and crushing the wet lithium carbonate to obtain a battery-grade lithium carbonate product.

[0030] The present invention uses lithium precipitation mother liquor as a raw material, and directly mixes it with an extractant for extraction without adjusting the alkali, thereby avoiding the need to supplement sodium salt or potassium salt to supplement alkalinity in the traditional lithium extraction process, and reducing the increase of metal ions in the water sample; at the same time, there is no need to carry out a concentration step for the lithium precipitation mother liquor, thereby reducing energy consumption and production costs, and at the same time, the lithium extraction rate and direct recovery rate are high.

[0031] The lithium carbonate prepared by the present invention has high purity, especially reducing the proportion of potassium and sodium salts in the lithium carbonate product, reaching the standard of battery-grade lithium carbonate, and solving the problems of complex purification process and high production cost of industrial-grade lithium carbonate prepared by traditional concentrated lithium precipitation.

[0032] The lithium precipitation mother liquor generated in the process of preparing lithium carbonate in the present invention is returned to the extraction section, thereby achieving full utilization of residual lithium resources in the lithium precipitation mother liquor. Meanwhile, no three wastes are generated in the production process, thereby avoiding environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0034] Figure 1The present invention is a process flow chart of a method for extracting and separating lithium from lithium precipitated mother liquor and preparing battery-grade lithium carbonate in accordance with an embodiment of the present invention.

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

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

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

[0038] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0039] Furthermore, the technical solutions between the various embodiments of the present invention may be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in the field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

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

[0041] like Figure 1 As shown, the method for extracting and separating lithium from lithium precipitate mother liquor and preparing battery-grade lithium carbonate provided by an embodiment of the present invention includes:

[0042] S1, fully mixing the extractant with the lithium precipitation mother liquor to obtain a raffinate and a lithium-loaded organic phase;

[0043] S2, mixing the lithium-loaded organic phase obtained in step S1 with pure water or acid solution for washing;

[0044] S3, mixing the washed lithium-loaded organic phase obtained in step S2 with an acid solution of a certain concentration for stripping;

[0045] S4, returning the blank organic phase obtained in step S3 to step S1 for re-extraction; mixing the lithium-rich solution with a certain concentration of soda ash solution to precipitate lithium;

[0046] S5, returning the lithium precipitation mother liquor obtained in step S4 to step S1 for re-extraction; drying and crushing the wet lithium carbonate to obtain a battery-grade lithium carbonate product.

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

[0048] In one embodiment, the extractant in step S1 includes one or more of 2-thenoyltrifluoroacetone, octylbenzoylmethane, dibenzoylmethane, nitrilotriacetic acid, benzoyltrifluoroacetone, trifluorotoluene diacetate, 2-furoyltrifluoroacetone, tributyl phosphate, trialkylphosphine oxide, 2-ethylhexyl phosphoric acid, and trioctylphosphine oxide.

[0049] In one embodiment, a diluent is added in step S1, and 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 phase ratio in step S2 is 1:1-30:1.

[0052] In one embodiment, the washing liquid in step S2 may 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-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-8 mol / L.

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

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

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

[0057] Wherein, in step S3, the pH of the mixing chamber can be controlled at 0-6 to ensure that the stripping process is fully carried out.

[0058] The present application is explained below through various specific embodiments.

[0059] Example 1

[0060] A method for extracting and separating lithium from lithium precipitate mother liquor and preparing battery-grade lithium carbonate, the process method is as follows Figure 1 As shown, the following steps are performed: Step S1, the lithium-loaded mother liquor is fully mixed with the extractant in a mixing and stirring chamber, the ratio of the extractant to the lithium-loaded mother liquor is 2:1, three mixing and clarifying chambers are used, and after countercurrent extraction three times, the lithium-loaded organic phase and the raffinate are obtained, and the pH of the extraction chamber is detected 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 also uses three mixing and clarifying chambers, and the washing water is returned to the mixing and stirring chamber in step S1 for re-extraction. Step S3, 3mol / L sulfuric acid solution is used to fully mix the lithium-loaded organic phase in a mixing and stirring chamber, the sulfuric acid solution is 20:1 compared with the lithium-loaded organic phase, and after countercurrent stripping twice, a blank organic phase and a lithium-rich solution product are obtained, and the pH of the mixing chamber is monitored to be 3.98. Step S4, according to the lithium content of the lithium-rich solution, 1.5mol / L of soda ash solution is added, and the reaction temperature is maintained at 95 degrees Celsius. After adding, continue stirring the reaction for 1h and filter to obtain the lithium-loaded mother liquor and wet lithium carbonate. Step S5, returning the lithium precipitation mother liquor obtained in step S4 to the mixing and stirring chamber in S1 for cyclic lithium extraction, drying and crushing the wet lithium carbonate to obtain a battery-grade lithium carbonate product.

[0061] Among them, the lithium content of the lithium precipitation mother liquor mentioned in step S1 is 2782 mg / L, and the calcium ion content is 4.2 mg / L; the obtained raffinate is analyzed by ICP (inductively coupled plasma mass spectrometry), and the lithium ion content of the raffinate is 7 mg / L, and the extraction rate reaches 99.7%. Through gas chromatography analysis, the oil content in the aqueous phase is 4 mg / L.

[0062] The lithium-rich solution obtained in step S3 has a lithium ion content of 27.2 g / L, a stripping rate of 97.7%, and an extraction stage yield of 97.4%.

[0063] Step S5, after drying at 260°C, the lithium carbonate product obtained by crushing has the following composition as shown in Table 1, which shows the main components and impurities of lithium carbonate (unit: %).

[0064]

[0065] Table 1

[0066] Example 2

[0067] A method for extracting and separating lithium from lithium precipitate mother liquor and preparing battery-grade lithium carbonate, the process method is as follows Figure 1 As shown, the following steps are performed: Step S1, the lithium-loaded mother liquor is fully mixed with the extractant in a mixing and stirring chamber, the ratio of the extractant to the lithium-loaded mother liquor is 3:1, three mixing and clarifying chambers are used, and after countercurrent extraction three times, the lithium-loaded organic phase and the raffinate are obtained, and the pH of the extraction chamber is detected 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 also uses three mixing and clarifying chambers, and the washing water is returned to the mixing and stirring chamber in step S1 for re-extraction. Step S3, 2mol / L sulfuric acid solution is used to fully mix the lithium-loaded organic phase in a mixing and stirring chamber, the sulfuric acid solution is 15:1 compared with the lithium-loaded organic phase, and after countercurrent stripping twice, a blank organic phase and a lithium-rich solution product are obtained, and the pH of the mixing chamber is monitored to be 4.12. Step S4, 1mol / L of soda ash solution is added according to the lithium content of the lithium-rich solution, and the reaction temperature is maintained at 95 degrees Celsius. After adding, continue stirring the reaction for 1h and filter to obtain the lithium-loaded mother liquor and wet lithium carbonate. Step S5, returning the lithium precipitation mother liquor obtained in step S4 to the mixing and stirring chamber in S1 for cyclic lithium extraction, drying and crushing the wet lithium carbonate to obtain a battery-grade lithium carbonate product.

[0068] Among them, the lithium content of the lithium precipitation mother liquor mentioned in step S1 is 2804 mg / L, and the calcium ion content is 8.4 mg / L; the obtained raffinate is analyzed by ICP (inductively coupled plasma mass spectrometry), and the lithium ion content of the raffinate is 6 mg / L, and the extraction rate reaches 99.7%. Through gas chromatography analysis, the oil content in the aqueous phase is 8 mg / L.

[0069] The lithium-rich solution obtained in step S3 has a lithium ion content of 13.6 g / L, a stripping rate of 97.3%, and an extraction stage yield of 97.0%.

[0070] Among them, in step S5, after drying at a temperature of 300° C., the composition of the lithium carbonate product obtained by crushing is shown in Table 2 below, which shows the main components and impurities of lithium carbonate (unit: %).

[0071]

[0072] Table 2

[0073] Example 3

[0074] A method for extracting and separating lithium from lithium precipitate mother liquor and preparing battery-grade lithium carbonate, the process method is as follows Figure 1As shown, the following steps are performed: Step S1, the lithium-precipitated mother liquor is fully mixed with the extractant in a mixing and stirring chamber, the ratio of the extractant to the lithium-precipitated mother liquor is 1.5:1, three mixing and clarifying chambers are used, and after countercurrent extraction three times, a lithium-loaded organic phase and a raffinate are obtained, and the pH of the extraction chamber is detected to be 7.7. Step S2, a certain amount of 0.05mol / 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 also used for washing, and the washing water is returned to the mixing and stirring chamber in step S1 for re-extraction. Step S3, 5mol / L hydrochloric acid solution is used to fully mix the lithium-loaded organic phase in a mixing and stirring chamber, the hydrochloric acid solution is compared with the lithium-loaded organic phase at a ratio of 15:1, and after countercurrent stripping twice, a blank organic phase and a lithium-rich solution product are obtained, and the pH of the monitoring mixing chamber is 4.32. Step S4, add 2 mol / L soda ash solution according to the lithium content of the lithium-rich solution, keep the reaction temperature at 95 degrees Celsius, continue stirring the reaction for 1.5 hours, and 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 cyclic extraction of lithium, dry and crush the wet lithium carbonate, and obtain a battery-grade lithium carbonate product.

[0075] Among them, the lithium content of the lithium precipitation mother liquor mentioned in step S1 is 2886 mg / L, and the calcium ion content is 3.6 mg / L; the obtained raffinate is analyzed by ICP (inductively coupled plasma mass spectrometry), and the lithium ion content of the raffinate is 11 mg / L, and the extraction rate reaches 99.6%. Through gas chromatography analysis, the oil content in the aqueous phase is 5 mg / L.

[0076] The lithium-rich solution obtained in step S3 has a lithium ion content of 27.7 g / L, a stripping rate of 96.1%, and an extraction stage yield of 95.7%.

[0077] Among them, in step S5, after the drying temperature is 400°C, the lithium carbonate product obtained by crushing meets the battery-grade lithium carbonate standard, and its composition is shown in the following Table 3, which shows the main components and impurities of lithium carbonate (unit %).

[0078]

[0079] Table 3

[0080] 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 changes made by using the contents of the present invention specification and drawings under the concept of the present invention, or directly / indirectly applied in other related technical fields are included in 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 precipitated mother liquor and preparing battery-grade lithium carbonate comprises: S1, fully mixing the extractant with the lithium precipitation mother liquor to obtain a raffinate and a lithium-loaded organic phase; S2, mixing the lithium-loaded organic phase obtained in step S1 with pure water or acid solution for washing; S3, mixing the washed lithium-loaded organic phase obtained in step S2 with an acid solution of a certain concentration for stripping; S4, returning the blank organic phase obtained in step S3 to step S1 for re-extraction; mixing the lithium-rich solution with a certain concentration of soda ash solution to precipitate lithium; S5, returning the lithium precipitation mother liquor obtained in step S4 to step S1 for re-extraction; drying and crushing the wet lithium carbonate to obtain a battery-grade lithium carbonate product.

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

5.

3. The method for extracting and separating lithium from lithium precipitate 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-thenoyltrifluoroacetone, octylbenzoylmethane, dibenzoylmethane, nitrilotriacetic acid, benzoyltrifluoroacetone, trifluorotoluene diacetate, 2-furoyltrifluoroacetone, tributyl phosphate, trialkylphosphine oxide, 2-ethylhexyl phosphoric acid, and trioctylphosphine oxide.

4. The method for extracting and separating lithium from lithium precipitate mother liquor and preparing battery-grade lithium carbonate according to claim 1, characterized in that: In the step S1, a diluent is added, and the diluent 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 precipitated 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 precipitated mother liquor and preparing battery-grade lithium carbonate according to claim 1, characterized in that: The washing phase ratio in step S2 is 1:1-30:

1.

7. The method for extracting and separating lithium from lithium precipitated mother liquor and preparing battery-grade lithium carbonate according to claim 1, characterized in that: The washing liquid in step S2 may 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-0.5 mol / L.

8. The method for extracting and separating lithium from lithium precipitated 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-8 mol / L.

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

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

Images