Leaching method and use of waste ternary material cathode powder

Abstract

This invention provides a leaching method for waste ternary cathode material and its application. The method includes the following steps: (1) mixing waste ternary cathode material with a mixed acid solution, reacting, and separating to obtain filtrate and filter residue; wherein the mixed acid solution is a combination solution of hydrochloric acid and organic acid solution; (2) mixing the filter residue with a detergent, washing, and separating to obtain washing liquid and filter cake; (3) mixing the filtrate from step (1) and the washing liquid from step (2) to obtain leaching solution. This leaching method does not require calcination treatment or the addition of external oxidants or reducing agents. With the synergistic effect of hydrochloric acid and organic acids, it not only simplifies the leaching process, reduces recycling costs, and increases economic benefits, but also avoids the pollution of the environment by valuable metals in waste ternary materials. It efficiently realizes the recycling and utilization of waste ternary cathode material, which is of great significance for the low-cost and high-efficiency recycling of waste batteries and the upgrading of industry technology.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery recycling technology, specifically relating to a leaching method for waste ternary cathode material and its application. Background Technology

[0002] The main cathode materials for lithium-ion batteries include lithium cobalt oxide, lithium manganese oxide, and ternary materials. Among them, ternary materials, with their superior performance, have been widely used in battery applications. With the ban on the sale of gasoline-powered vehicles in Europe and the United States and the rapid development of new energy vehicles in China, a number of power battery manufacturers have emerged, such as Panasonic of Japan, Samsung and LG Chem of South Korea, Tesla's Gigafactory, CATL, Huayou Cobalt, GEM, and BYD. The production and sales of new energy vehicles have experienced explosive growth, and the lithium battery industry has ushered in its "golden age."

[0003] Generally, the lifespan of lithium-ion batteries in consumer electronics is 1-3 years, while that of power batteries is 5-8 years. After years of development, the earliest lithium-ion batteries on the market are entering their retirement period. Retired lithium-ion batteries contain a large amount of high-value metals, with lithium content ranging from 1% to 4%, and cobalt and nickel content reaching 10% to 20% in ternary lithium batteries, making them extremely valuable economically. Therefore, the economical and effective recycling of waste lithium-ion batteries will help obtain a large amount of high-quality secondary metal resources, alleviate the raw material shortage caused by the strong demand for lithium-ion batteries, and promote the sustainable development and upgrading of the lithium-ion battery industry.

[0004] The wet recycling of valuable metals from spent ternary lithium-ion battery cathode materials is attracting increasing attention due to its advantages such as high metal recovery rate, simple process, and high product purity. CN112646974A discloses a method for recovering valuable metals from spent ternary lithium-ion battery cathode materials. Its main feature is the roasting of pre-treated spent ternary cathode powder, followed by water leaching and selective lithium extraction to preferentially recover lithium salts. Subsequently, a nickel-cobalt-manganese sulfate solution is obtained through acid leaching, impurity removal, and extraction, which is then used as a raw material to directly prepare ternary precursors. CN103199320B discloses a method for recycling nickel-cobalt-manganese ternary cathode materials. This method involves discharging, crushing, and roasting spent ternary lithium-ion battery materials, followed by leaching with an inorganic strong acid and reducing agent to dissolve and extract the valuable metals from the cathode materials. The leachate undergoes impurity removal and extraction processes to recover nickel, cobalt, and manganese. A precipitant is added to the leachate to obtain lithium products.

[0005] The above method has enabled the recycling of nickel-cobalt-manganese ternary cathode materials, but it has the following drawbacks: the waste lithium battery needs to be roasted before leaching, and an additional reducing agent needs to be added during the inorganic acid leaching process to ensure the leaching effect. The leaching process is complex and the recycling cost is high.

[0006] Therefore, how to simplify the leaching process, reduce recycling costs, and improve the leaching rate is an urgent technical problem to be solved. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a leaching method for waste ternary cathode material and its applications. The leaching method provided by this invention requires no roasting treatment or the addition of any external oxidizing or reducing agents. Utilizing the synergistic effect of hydrochloric acid and organic acids, it not only simplifies the leaching process, reduces recycling costs, and increases economic benefits, but also avoids environmental pollution from valuable metals in waste ternary materials. This highly efficient recycling of waste ternary cathode material is of great significance for the low-cost, high-efficiency recycling of waste batteries and for the technological upgrading of the industry.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a leaching method for waste ternary cathode material, the method comprising the following steps:

[0010] (1) The waste ternary cathode material and mixed acid solution are mixed and reacted to obtain filtrate and filter residue;

[0011] The mixed acid solution is a combination solution of hydrochloric acid and organic acid solution;

[0012] (2) The filter residue and detergent are mixed and washed to separate the washing liquid and filter cake;

[0013] (3) Mix the filtrate from step (1) and the washing solution from step (2) to obtain an extract.

[0014] This invention utilizes the synergistic effect of hydrochloric acid and organic acid solutions. Hydrochloric acid helps improve the leaching efficiency of valuable elements in ternary cathode powder, while organic acids have the dual function of leaching aid and reducing agent. The two work together to significantly improve the leaching rate of ternary cathode powder. Combined with filter residue treatment, this invention achieves efficient recovery of valuable metals from waste ternary cathode powder. This leaching method does not require roasting treatment or the addition of any oxidizing or reducing agents, which not only simplifies the leaching process, reduces recycling costs, and increases economic benefits, but also effectively avoids environmental pollution caused by valuable metals in waste ternary materials. This is of great significance for the low-cost and efficient recycling of waste batteries and the upgrading of industry technology.

[0015] In this invention, the filtrate and washing liquid are mixed to obtain a leachate, which can better improve the lithium recovery rate and reduce lithium loss.

[0016] It should be noted that if only hydrochloric acid is used to treat waste ternary cathode materials, it will be difficult to completely leach out high-valence elements such as cobalt and manganese in the ternary cathode powder.

[0017] Preferably, the mass content of the solute in the hydrochloric acid in step (1) is 25-38%, for example, it can be 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35% or 36%, etc.

[0018] In this invention, if the mass content of the solute in hydrochloric acid is too low, the leaching rate of valuable metal elements will be reduced.

[0019] Preferably, the organic acid in the organic acid solution in step (1) includes any one or a combination of at least two of formic acid, acetic acid, ascorbic acid, lactic acid, citric acid, methanesulfonic acid, tartaric acid or benzenesulfonic acid, and is preferably any one or a combination of at least two of lactic acid, ascorbic acid or citric acid.

[0020] Preferably, the concentration of the organic acid solution in step (1) is 0.2-4 mol / L, for example, it can be 0.2 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, 3.5 mol / L or 4 mol / L, etc.

[0021] Preferably, the volume ratio of hydrochloric acid and organic acid solution in step (1) is (2-40):1, for example, it can be 2:1, 5:1, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1 or 40:1, etc., preferably (5-20):1.

[0022] In this invention, if the volume ratio of hydrochloric acid to organic acid solution is too small, that is, the amount of organic acid solution used is too high, the leaching rate of low-valence valuable elements during the reaction process will be low; if the volume ratio of hydrochloric acid to organic acid solution is too high, that is, the amount of organic acid solution used is too low, high-valence elements such as cobalt and manganese will be difficult to be reduced and leached.

[0023] Preferably, the solid-liquid ratio of the waste ternary material and the mixed acid solution in step (1) is 1g:(3-5)mL, for example, it can be 1g:3mL, 1g:3.3mL, 1g:3.6mL, 1g:3.9mL, 1g:4.2mL, 1g:4.5mL or 1g:5mL, etc.

[0024] Preferably, the mixing process in step (1) is accompanied by stirring.

[0025] Preferably, the mixing temperature in step (1) is 20-90°C, for example, it can be 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C or 90°C.

[0026] Preferably, the reaction time in step (1) is 20-200 min, for example, it can be 20 min, 40 min, 60 min, 80 min, 100 min, 120 min, 140 min, 160 min, 180 min or 200 min, etc., and preferably 50-100 min.

[0027] Preferably, the waste ternary cathode material in step (1) includes nickel-cobalt-manganese ternary cathode material.

[0028] Preferably, the detergent in step (2) comprises water.

[0029] Preferably, the mass ratio of the filter residue to the detergent in step (2) is 1:(1-5), for example, it can be 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5 or 1:5, etc.

[0030] Preferably, the washing time in step (2) is 30-60 minutes, for example, it can be 30 minutes, 40 minutes, 50 minutes or 60 minutes.

[0031] Preferably, the washing temperature in step (2) is 20-100℃, for example, it can be 20℃, 30℃, 40℃, 50℃, 60℃, 70℃, 80℃, 90℃ or 100℃.

[0032] Preferably, hydrochloric acid is added during the washing process described in step (2).

[0033] In one embodiment, the hydrochloric acid has the same mass content of solute as the hydrochloric acid in step (1).

[0034] In this invention, the purpose of adding hydrochloric acid during the washing process described in step (2) is to wash away all the valuable elements carried in the leaching residue into the solution for recycling.

[0035] Preferably, the amount of hydrochloric acid added satisfies the following condition: the pH value of the solution after washing is 1-5, for example, it can be 1, 2, 3, 4 or 5.

[0036] Preferably, the method further includes recovering metal ions from the leachate in step (3), wherein the recovery method includes:

[0037] Metal ions in the leachate are recovered in stages by adjusting the pH value of the leachate.

[0038] In one embodiment, adjusting the pH of the leachate to 1.0-2.0 allows for the separation of manganese; adjusting the pH of the leachate to 7.0-9.0 allows for the recovery of nickel and cobalt; and adjusting the pH of the leachate to 11.0-13.0 allows for the recovery of lithium.

[0039] As a preferred technical solution, the method includes the following steps:

[0040] (1) According to the solid-liquid ratio of 1g:(3-5)mL, the waste ternary material positive electrode powder and mixed acid solution are mixed at 20-90℃ and stirred for 20-200min to react, and the filtrate and filter residue are separated.

[0041] The mixed acid solution includes hydrochloric acid and organic acid solution, wherein the mass content of solute in the hydrochloric acid is 25-38%, the concentration of the organic acid solution is 0.2-4.0 mol / L, and the volume ratio of hydrochloric acid to organic acid solution is (2-40):1.

[0042] (2) Mix the filter residue with water at a mass ratio of 1:(1-5) and wash at 20-100℃ for 30-60 min. Hydrochloric acid is also added during the washing process to make the pH value of the solution after washing 1-5. Separate the washing liquid and filter cake.

[0043] (3) Mix the filtrate from step (1) and the washing solution from step (2) to obtain an extract. By adjusting the pH value of the extract, the metal ions in the waste ternary cathode powder are recovered step by step.

[0044] Secondly, the present invention provides an application of the method as described in the first aspect, the method being used for the recycling and reuse of waste lithium-ion batteries.

[0045] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] (1) This invention utilizes the synergistic effect of hydrochloric acid and organic acid solutions. Hydrochloric acid helps to improve the leaching efficiency of valuable elements in ternary cathode powder, while organic acid has the dual function of leaching aid and reducing agent. The two work together to significantly improve the leaching rate of ternary cathode powder. At the same time, combined with the filter residue treatment process, it realizes the efficient recovery of valuable metals in waste ternary cathode powder, and the leaching rate of metal ions exceeds 95%.

[0048] (2) The leaching method provided by the present invention does not require roasting treatment or the addition of any oxidizing or reducing agent. It not only simplifies the leaching process, reduces recycling costs, and increases economic benefits, but also effectively avoids the pollution of the environment by valuable metals in waste ternary materials. This is of great significance for the low-cost and efficient recycling of waste batteries and the upgrading of industry technology. Detailed Implementation

[0049] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0050] Example 1

[0051] This embodiment provides a leaching method for waste ternary cathode material, the method comprising the following steps:

[0052] (1) According to the solid-liquid ratio of 1g:3mL, 35g of waste nickel-cobalt-manganese ternary material cathode powder and 105mL of mixed acid solution were mixed in an oil bath at 60℃ and stirred for 140min to react, and the filtrate and filter residue were separated.

[0053] The mixed acid solution includes hydrochloric acid and formic acid solutions, wherein the mass content of the solute in the hydrochloric acid is 32%, the concentration of the formic acid solution is 2 mol / L, and the volume ratio of the hydrochloric acid to the formic acid solution is 20:1.

[0054] (2) The filter residue and water were mixed in a mass ratio of 1:3 and washed at 60°C for 45 minutes. During the washing process, hydrochloric acid with a mass content of 32% was added to make the pH value of the solution after washing 3. The washing liquid and filter cake were then separated.

[0055] (3) Mix the filtrate from step (1) and the washing solution from step (2) to obtain an extract. By adjusting the pH value of the extract, the metal ions in the waste ternary cathode powder are recovered step by step.

[0056] Example 2

[0057] This embodiment provides a leaching method for waste ternary cathode material, the method comprising the following steps:

[0058] (1) According to the solid-liquid ratio of 1g:4mL, 12g of waste nickel-cobalt-manganese ternary material cathode powder and 48mL of mixed acid solution were mixed in an oil bath at 20℃ and stirred for 200min to react, and the filtrate and filter residue were separated.

[0059] The mixed acid solution includes hydrochloric acid and ascorbic acid solution, wherein the mass content of the solute in the hydrochloric acid is 25%, the concentration of the ascorbic acid solution is 0.5 mol / L, and the volume ratio of the hydrochloric acid solution to the ascorbic acid solution is 5:1.

[0060] (2) Mix the filter residue and water in a mass ratio of 1:1 and wash at 20°C for 60 min. During the washing process, add hydrochloric acid with a mass content of 25% solute to make the pH value of the solution after washing 5. Separate the washing liquid and filter cake.

[0061] (3) Mix the filtrate from step (1) and the washing solution from step (2) to obtain an extract. By adjusting the pH value of the extract, the metal ions in the waste ternary cathode powder are recovered step by step.

[0062] Example 4

[0063] The difference between this embodiment and embodiment 1 is that the mass fraction of the solute in the hydrochloric acid in step (1) is 20%.

[0064] The remaining preparation methods and parameters are consistent with those in Example 1.

[0065] Example 5

[0066] The difference between this embodiment and embodiment 1 is that the volume ratio of hydrochloric acid and formic acid solution in step (1) is 1:1.

[0067] The remaining preparation methods and parameters are consistent with those in Example 1.

[0068] Example 6

[0069] The difference between this embodiment and embodiment 1 is that the volume ratio of hydrochloric acid and formic acid solution in step (1) is 45:1.

[0070] The remaining preparation methods and parameters are consistent with those in Example 1.

[0071] Example 7

[0072] The difference between this embodiment and embodiment 1 is that hydrochloric acid is not added during the washing process in step (2).

[0073] The remaining preparation methods and parameters are consistent with those in Example 1.

[0074] Comparative Example 1

[0075] The difference between this comparative example and Example 1 is that in step (1), only 105 mL of hydrochloric acid is added, and no formic acid solution is added.

[0076] The remaining preparation methods and parameters are consistent with those in Example 1.

[0077] Comparative Example 2

[0078] The difference between this comparative example and Example 1 is that in step (1), only 105 mL of formic acid solution is added, and hydrochloric acid is not added.

[0079] The remaining preparation methods and parameters are consistent with those in Example 1.

[0080] Comparative Example 3

[0081] The difference between this comparative example and Example 1 is that step (2) is omitted.

[0082] The remaining preparation methods and parameters are consistent with those in Example 1.

[0083] Performance testing

[0084] The metal ion leaching rate of the leachates prepared in Examples 1-7 and Comparative Examples 1-3 was tested. The test procedure included the following steps:

[0085] The filter cakes provided in Examples 1-7 and Comparative Example 1 were alkali-melted at 950°C for 30 min. After melting, they were dissolved in hydrochloric acid and then tested using an inductively coupled plasma optical generator (ICP). The test result was recorded as m%. The leaching rate of metal ions in the leachate was 1-m.

[0086] The test results are shown in Table 1.

[0087] Table 1

[0088]

[0089] analyze:

[0090] As shown in the table above, the leaching method provided by this invention achieves efficient recovery of valuable metals from waste ternary cathode powder, with the leaching rate of metal ions exceeding 95%.

[0091] A comparison of the data results from Example 1 and Example 4 shows that a low concentration of hydrochloric acid will reduce the leaching rate of valuable metal elements.

[0092] A comparison of the data results from Examples 1 and 5-6 shows that if the volume ratio of hydrochloric acid to organic acid solution is too small, the leaching rate of low-valence valuable elements such as nickel and lithium will be low during the reaction process; if the volume ratio of hydrochloric acid to organic acid solution is too large, high-valence elements such as cobalt and manganese will be difficult to be reduced and leached.

[0093] A comparison of the data results from Example 1 and Example 7 shows that adding hydrochloric acid during the filter residue washing process can wash away all the valuable elements entrained in the leaching residue and bring them into the solution for recycling.

[0094] A comparison of the data results of Example 1 and Comparative Example 1 shows that if only hydrochloric acid is added to recycle waste ternary cathode powder, the leaching efficiency is poor and the cost is high.

[0095] A comparison of the data results from Example 1 and Comparative Example 2 shows that if only formic acid solution is added to recycle the waste ternary cathode powder, the leaching efficiency of valuable metals in the waste ternary material will decrease significantly.

[0096] A comparison of the data results from Example 1 and Comparative Example 3 shows that if the separated filter residue is not treated, the lithium recovery rate cannot be improved, and the lithium loss is significant.

[0097] The applicant declares that the present invention is illustrated by the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A leaching method for waste ternary cathode material, characterized in that, The method includes the following steps: (1) The waste ternary cathode material and mixed acid solution are mixed and reacted to obtain filtrate and filter residue; The mixed acid solution is a combination solution of hydrochloric acid and organic acid solution; (2) The filter residue and detergent are mixed and washed to separate the washing liquid and filter cake; (3) Mix the filtrate from step (1) and the washing solution from step (2) to obtain a leachate. By adjusting the pH value of the leachate, the metal ions in the leachate are recovered step by step. The mass content of the solute in the hydrochloric acid mentioned in step (1) is 25-36%; The volume ratio of hydrochloric acid to organic acid solution in step (1) is (5-20):1; Hydrochloric acid is also added during the washing process described in step (2); The concentration of the organic acid solution in step (1) is 0.2-4 mol / L; In step (1), the solid-liquid ratio of the waste ternary material and the mixed acid solution is 1g:(3-5)mL; The amount of hydrochloric acid added satisfies the following condition: the pH value of the solution after washing is 1-5.

2. The method according to claim 1, characterized in that, The organic acids in the organic acid solution in step (1) include any one or a combination of at least two of formic acid, acetic acid, ascorbic acid, lactic acid, citric acid, methanesulfonic acid, tartaric acid, or benzenesulfonic acid.

3. The method according to claim 2, characterized in that, The organic acid in the organic acid solution mentioned in step (1) is any one or a combination of at least two of formic acid, ascorbic acid or citric acid.

4. The method according to claim 1, characterized in that, The mixing process described in step (1) is accompanied by stirring.

5. The method according to claim 1, characterized in that, The mixing temperature in step (1) is 20-90℃.

6. The method according to claim 1, characterized in that, The reaction time in step (1) is 20-200 min.

7. The method according to claim 6, characterized in that, The reaction time in step (1) is 50-100 min.

8. The method according to claim 1, characterized in that, The waste ternary cathode material in step (1) includes nickel-cobalt-manganese ternary cathode material.

9. The method according to claim 1, characterized in that, The detergent in step (2) includes water.

10. The method according to claim 1, characterized in that, In step (2), the mass ratio of the filter residue to the detergent is 1:(1-5).

11. The method according to claim 1, characterized in that, The washing time in step (2) is 30-60 minutes.

12. The method according to claim 1, characterized in that, The washing temperature in step (2) is 20-100℃.

13. The method according to claim 1, characterized in that, The method includes the following steps: (1) According to the solid-liquid ratio of 1g:(3-5)mL, the waste ternary material positive electrode powder and mixed acid solution are mixed at 20-90℃ and stirred for 20-200min to react, and the filtrate and filter residue are separated. The mixed acid solution includes hydrochloric acid and organic acid solution, wherein the mass content of solute in the hydrochloric acid is 25-36%, the concentration of the organic acid solution is 0.2-4 mol / L, and the volume ratio of hydrochloric acid to organic acid solution is (5-20):

1. (2) Mix the filter residue with water at a mass ratio of 1:(1-5) and wash at 20-100℃ for 30-60 min. Hydrochloric acid is also added during the washing process to make the pH value of the solution after washing 1-5. Separate the washing liquid and filter cake. (3) Mix the filtrate from step (1) and the washing solution from step (2) to obtain an extract. By adjusting the pH value of the extract, the metal ions in the waste ternary cathode powder are recovered step by step.

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