Process for producing battery-grade lithium carbonate from waste water solution containing lithium and sodium recovered from ternary battery

Description

Process for producing battery-grade lithium carbonate from lithium-sodium-containing wastewater solution recovered from ternary batteries TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium extraction, in particular to a process for producing battery-grade lithium carbonate from lithium-sodium-containing wastewater solution recovered from ternary batteries. BACKGROUND

[0002] A large number of used and scrapped ternary batteries need to be safely, environmentally and efficiently treated every year. Therefore, the process for producing battery-grade lithium carbonate from lithium-sodium-containing wastewater solution recovered from ternary batteries is widely studied. The solvent extraction method in the existing lithium extraction process has the advantages of simple operation, high efficiency and low cost, and has been rapidly researched and developed in the field of lithium extraction. However, there are still defects such as insufficient lithium extraction effect and low lithium carbonate yield. Therefore, it is necessary to develop a production process for improving the yield of lithium carbonate to promote the recycling of ternary battery wastewater solution. SUMMARY

[0003] The present application provides a process for producing battery-grade lithium carbonate from lithium-sodium-containing wastewater solution recovered from ternary batteries, which solves the problem of low yield in the related art when extracting lithium carbonate.

[0004] The technical solution of the present application is as follows:

[0005] The present application provides a process for producing battery-grade lithium carbonate from lithium-sodium-containing wastewater solution recovered from ternary batteries, which includes the following steps:

[0006] S1, adding activated carbon to the lithium-sodium-containing wastewater solution and mixing to obtain a pretreated solution;

[0007] S2, adding an extractant to the pretreated solution and mixing, and after first post-treatment, lithium is precipitated to obtain lithium precipitation slurry and lithium precipitation mother liquor;

[0008] S3, second post-treatment of the lithium precipitation slurry to obtain battery-grade lithium carbonate;

[0009] In step S2, the extractant includes 2-ethylhexyl 2-ethylhexyl phosphate and 1-ethyl methyl-3-methyl imidazole tetra borate.

[0010] As a further technical solution, the mass ratio of 2-ethylhexyl 2-ethylhexyl phosphate and 1-ethyl methyl-3-methyl imidazole tetra borate is 3:2 to 4:1.

[0011] In the application, by adjusting the mass ratio of 2-ethylhexyl phosphate 2-ethylhexyl ester and 1-ethyl methyl-3-methyl imidazole tetra borate to 3:2-4:1, the yield of producing battery grade lithium carbonate from lithium sodium containing wastewater solution recovered from ternary battery is further improved.

[0012] As a further technical solution, in step S1, the mixing time is 40-50 min; in step S2, the mixing time is 60-90 min.

[0013] As a further technical solution, the first post-treatment comprises evaporation concentration, continuous flash evaporation and freeze crystallization, alkali impurity removal, and resin column filtration treatment in sequence; the second post-treatment comprises filtration, washing, drying, and crushing treatment in sequence.

[0014] As a further technical solution, the alkali impurity removal is performed at a temperature of 80-90℃, a pH of 11-12, and a time of 30-60 min.

[0015] As a further technical solution, the resin type in the resin column is one or more of LS-1000, CH-93, CH-90, and LSC-500.

[0016] As a further technical solution, the resin type in the resin column is one or both of CH-90 and LSC-500.

[0017] In the application, resin column is used to adsorb calcium and magnesium ions, and especially when the resin type of the resin column is CH-90 or LSC-500, the purity of battery grade lithium carbonate produced from lithium sodium containing wastewater solution recovered from ternary battery can be further improved.

[0018] As a further technical solution, the lithium precipitation mother liquor can be mixed with sulfuric acid for acidification, the pH value is controlled to be 2-4, the acidification reaction time is greater than 30 min, then liquid alkali is added for pH adjustment, the pH value is controlled to be 7-8, and the mixed solution containing lithium and sodium after acidification can be returned to the raw material section for recycling.

[0019] As a further technical solution, the particle size of the battery grade lithium carbonate is 4-6 μm.

[0020] As a further technical solution, sodium carbonate is added during lithium precipitation and reacted at 90-95℃ for 3-4 h.

[0021] The working principle and beneficial effects of the application are as follows:

[0022] In the present application, 2-ethylhexyl phosphonic acid 2-ethylhexyl ester and 1-ethyl methyl-3-methyl imidazole tetra borate are used as extractants to extract lithium carbonate, and the two work together to significantly improve the yield of battery-grade lithium carbonate produced from lithium-sodium-containing wastewater solution recovered from a ternary battery. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0024] Embodiment 1

[0025] A process for producing battery-grade lithium carbonate from lithium-sodium-containing wastewater solution recovered from a ternary battery includes the following steps:

[0026] S1, adding activated carbon to the lithium-sodium-containing wastewater solution and mixing for 40 min to obtain a pretreated solution;

[0027] S2, adding 200 mL of extractant to 500 mL of the pretreated solution and mixing for 60 min, then performing evaporation concentration, continuous flash evaporation and freeze crystallization, alkali impurity removal (impurity removal at 90°C and pH 11 for 30 min), resin column filtration treatment with a resin column of model CH-93, and then adding sodium carbonate and reacting at 90°C for 4 h to precipitate lithium to obtain a lithium precipitation slurry and a lithium precipitation mother liquor; the lithium precipitation mother liquor can be mixed with sulfuric acid for acidification, the pH value is controlled to be 2, the acidification reaction time is 50 min, then liquid alkali is added for pH adjustment, the pH value is controlled to be 8, and the mixed solution containing lithium and sodium after acidification can be returned to the raw material section for recycling;

[0028] S3, performing filter washing and drying three-in-one treatment on the lithium precipitation slurry, and then crushing to obtain battery-grade lithium carbonate with a particle size of 5 μm; wherein the extractant is 2-ethylhexyl phosphonic acid 2-ethylhexyl ester and 1-ethyl methyl-3-methyl imidazole tetra borate with a mass ratio of 1:4;

[0029] Calculation and detection show that the yield of lithium carbonate is 97.8%, and the purity is 99.0%.

[0030] Embodiment 2

[0031] A process for producing battery-grade lithium carbonate from lithium-sodium-containing wastewater solution recovered from a ternary battery includes the following steps:

[0032] S1, adding activated carbon to the lithium-sodium-containing wastewater solution and mixing for 50 min to obtain a pretreated solution;

[0033] S2, 400 mL of extractant is added to 500 mL of the pretreated solution for mixing for 90 min, concentrated by evaporation, continuous flash and frozen crystallization, alkali removal (removal at 80℃ and pH 12 for 60 min), resin column filtration containing resin with model CH-93, then sodium carbonate is added for reaction and lithium precipitation at 95℃ for 4 h to obtain lithium precipitation slurry and lithium precipitation mother liquor; the lithium precipitation mother liquor can be mixed with sulfuric acid for acidification, the pH value is controlled to be 4, the acidification reaction time is 60 min, then liquid alkali is added for pH adjustment, the pH value is controlled to be 7, and the mixed solution containing lithium sodium after acidification can be returned to the raw material section for recycling;

[0034] S3, after the lithium precipitation slurry is subjected to the three-in-one treatment of filtration, washing and drying, it is crushed to obtain battery-grade lithium carbonate with a particle size of 5 μm; wherein the extractant is 2-ethylhexyl phosphonic acid 2-ethylhexyl ester and 1-ethyl methyl-3-methyl imidazole tetra borate with a mass ratio of 1:4;

[0035] Through calculation and detection, the yield of lithium carbonate is 98.0%, and the purity is 99.0%.

[0036] Example 3

[0037] A process for producing battery-grade lithium carbonate from a wastewater solution containing lithium sodium in a ternary battery, comprising the following steps:

[0038] S1, active carbon is added to the wastewater solution containing lithium sodium for mixing for 45 min to obtain a pretreated solution;

[0039] S2, 300 mL of extractant is added to 500 mL of the pretreated solution for mixing for 75 min, concentrated by evaporation, continuous flash and frozen crystallization, alkali removal (removal at 90℃ and pH 11 for 50 min), resin column filtration containing resin with model CH-93, then sodium carbonate is added for reaction and lithium precipitation at 95℃ for 3 h to obtain lithium precipitation slurry and lithium precipitation mother liquor; the lithium precipitation mother liquor can be mixed with sulfuric acid for acidification, the pH value is controlled to be 3, the acidification reaction time is 60 min, then liquid alkali is added for pH adjustment, the pH value is controlled to be 8, and the mixed solution containing lithium sodium after acidification can be returned to the raw material section for recycling;

[0040] S3, after the lithium precipitation slurry is subjected to the three-in-one treatment of filtration, washing and drying, it is crushed to obtain battery-grade lithium carbonate with a particle size of 5 μm; wherein the extractant is 2-ethylhexyl phosphonic acid 2-ethylhexyl ester and 1-ethyl methyl-3-methyl imidazole tetra borate with a mass ratio of 1:4;

[0041] Through calculation and detection, the yield of lithium carbonate is 98.2%, and the purity is 99.1%.

[0042] Example 4

[0043] The difference between this example and Example 3 is that the extractant is 2-ethylhexyl phosphonic acid 2-ethylhexyl ester and 1-ethyl methyl-3-methyl imidazolium tetrafluoroborate in a mass ratio of 5:1.

[0044] The yield of lithium carbonate was calculated and measured to be 98.0% with a purity of 99.2%.

[0045] Example 5

[0046] The difference between this example and Example 3 is that the extractant is 2-ethylhexyl phosphonic acid 2-ethylhexyl ester and 1-ethyl methyl-3-methyl imidazolium tetrafluoroborate in a mass ratio of 3:2.

[0047] The yield of lithium carbonate was calculated and measured to be 99.3% with a purity of 99.2%.

[0048] Example 6

[0049] The difference between this example and Example 3 is that the extractant is 2-ethylhexyl phosphonic acid 2-ethylhexyl ester and 1-ethyl methyl-3-methyl imidazolium tetrafluoroborate in a mass ratio of 4:1.

[0050] The yield of lithium carbonate was calculated and measured to be 99.7% with a purity of 99.1%.

[0051] Example 7

[0052] The difference between this example and Example 6 is that the resin with model CH-93 is replaced by the resin with model LS-1000.

[0053] The purity of lithium carbonate was measured to be 99.2%.

[0054] Example 8

[0055] The difference between this example and Example 6 is that the resin with model CH-93 is replaced by the resin with model CH-90.

[0056] The purity of lithium carbonate was measured to be 99.6%.

[0057] Example 9

[0058] The difference between this example and Example 6 is that the resin with model CH-93 is replaced by the resin with model LSC-500.

[0059] The purity of lithium carbonate was measured to be 99.8%.

[0060] Comparative Example 1

[0061] The difference between this comparative example and Example 3 is that the extractant is 2-ethylhexyl phosphonic acid 2-ethylhexyl ester;

[0062] The yield of lithium carbonate was 94.0% by calculation and detection.

[0063] Comparative Example 2

[0064] The difference between this comparative example and Example 3 is that the extractant is 1-ethyl methyl-3-methyl imidazole tetra borate;

[0065] The yield of lithium carbonate was 93.5% by calculation and detection.

[0066] Comparative Example 3

[0067] The difference between this comparative example and Example 3 is that the extractant is tributyl phosphate and 1-ethyl methyl-3-methyl imidazole tetra borate;

[0068] The yield of lithium carbonate was 91.6% by calculation and detection.

[0069] Comparative Example 4

[0070] The difference between this comparative example and Example 3 is that the extractant is 2-ethylhexyl phosphoric acid 2-ethylhexyl ester and 1-ethyl-3-vinyl imidazole acetate;

[0071] The yield of lithium carbonate was 92.2% by calculation and detection.

[0072] By comparing the data of Examples 1-9 and Comparative Examples 1-4, it can be found that the yield of lithium carbonate obtained by Examples 1-9 is higher than that of Comparative Examples 1-4, which indicates that using 2-ethylhexyl phosphoric acid 2-ethylhexyl ester and 1-ethyl methyl-3-methyl imidazole tetra borate as the extractant for extracting lithium carbonate, significantly improves the yield of producing battery-grade lithium carbonate from the lithium-sodium-containing wastewater solution recovered from ternary batteries.

[0073] By comparing the data of Examples 3-6, it can be found that the yield of lithium carbonate obtained by Examples 5-6 is higher than that of Examples 3-4, which indicates that by adjusting the mass ratio of 2-ethylhexyl phosphoric acid 2-ethylhexyl ester and 1-ethyl methyl-3-methyl imidazole tetra borate to 3:2-4:1, further improves the yield of producing battery-grade lithium carbonate from the lithium-sodium-containing wastewater solution recovered from ternary batteries.

[0074] By comparing the data of Examples 6-9, it can be found that the purity of lithium carbonate obtained by Examples 8-9 is higher than that of Examples 6-7, which indicates that using a resin column to adsorb calcium and magnesium ions, especially when the resin type of the resin column is CH-90 or LSC-500, can further improve the purity of producing battery-grade lithium carbonate from the lithium-sodium-containing wastewater solution recovered from ternary batteries.

[0075] The above merely preferred embodiments of the present application are not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A process for producing battery-grade lithium carbonate by recovering lithium-sodium-containing wastewater from ternary lithium batteries, characterized in that, Includes the following steps: S1. Add activated carbon to the wastewater containing sodium lithium and mix to obtain a pretreated solution; S2. Add an extractant to the pretreatment solution and mix. After the first post-treatment, precipitate lithium to obtain lithium precipitation slurry and lithium precipitation mother liquor. S3. Perform a second post-processing on the lithium precipitation slurry to obtain battery-grade lithium carbonate; In step S2, the extractant includes 2-ethylhexyl phosphate 2-ethylhexyl ester and 1-ethyl ester methyl-3-methylimidazolium tetraborate.

2. The process for producing battery-grade lithium carbonate from lithium-sodium-containing wastewater in a ternary battery according to claim 1, characterized in that, The mass ratio of 2-ethylhexyl phosphate 2-ethylhexyl ester to 1-ethyl ester methyl-3-methylimidazolium tetraborate is 3:2 to 4:

1.

3. The process for producing battery-grade lithium carbonate from lithium-sodium-containing wastewater in a ternary battery according to claim 1, characterized in that, In step S1, the mixing time is 40-50 min; in step S2, the mixing time is 60-90 min.

4. The process for producing battery-grade lithium carbonate from lithium-sodium-containing wastewater in a ternary battery according to claim 1, characterized in that, The first post-treatment includes evaporation and concentration, continuous flash evaporation and freeze crystallization, alkaline impurity removal, and resin column filtration. The second post-treatment includes filtration, washing, drying, and pulverization.

5. The process for producing battery-grade lithium carbonate from lithium-sodium-containing wastewater in a ternary battery according to claim 3, characterized in that, The alkaline purification process is carried out at a temperature of 80–90°C, a pH of 11–12, and a time of 30–60 min.

6. The process for producing battery-grade lithium carbonate from lithium-sodium-containing wastewater in a ternary battery according to claim 3, characterized in that, The resin in the resin column is one or more of the following: LS-1000, CH-93, CH-90, and LSC-500.

7. The process for producing battery-grade lithium carbonate from lithium-sodium-containing wastewater in a ternary battery according to claim 6, characterized in that, The resin in the resin column is one or both of CH-90 and LSC-500.

8. The process for producing battery-grade lithium carbonate from lithium-sodium-containing wastewater in a ternary battery according to claim 1, characterized in that, The lithium precipitation mother liquor can be mixed with sulfuric acid for acidification, controlling the pH value to 2-4, and the acidification reaction time to be greater than 30 minutes. Then, liquid alkali is added to adjust the pH value to 7-8. The mixed liquor containing lithium and sodium after acidification can be returned to the raw material section for reuse.

9. The process for producing battery-grade lithium carbonate from lithium-sodium-containing wastewater in a ternary battery according to claim 1, characterized in that, The battery-grade lithium carbonate has a particle size of 4–6 μm.

10. The process for producing battery-grade lithium carbonate from lithium-sodium-containing wastewater in a ternary battery according to claim 1, characterized in that, Sodium carbonate is added during the lithium precipitation process, and the reaction is carried out at 90-95°C for 3-4 hours.