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CN-121450925-B - Process for extracting lithium from lithium battery waste

CN121450925BCN 121450925 BCN121450925 BCN 121450925BCN-121450925-B

Abstract

The invention relates to a process for extracting lithium from lithium battery waste, and belongs to the technical field of lithium extraction. According to the invention, the mixed solution of the phosphoric acid solution, the sodium citrate and the sodium persulfate is used for primary leaching, the leaching slag is subjected to secondary leaching by the phosphoric acid solution, the solutions of the two leaching are combined and then subjected to staged adjustment of the pH value of the solution or adsorption treatment by the adsorbent for purification and impurity removal, and the process flow is simple, so that high lithium recovery rate can be obtained.

Inventors

  • WEI ZENG

Assignees

  • 上海意定新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20251010

Claims (7)

  1. 1. The process for extracting lithium from lithium battery waste is characterized by comprising the following steps of: S1, pyrolyzing lithium battery waste at 350-400 ℃ in an inert atmosphere for 1-2 hours, and stripping to obtain a pretreatment material; S2, lithium leaching, namely mixing the pretreated material with primary leaching solution, stirring at 200rpm for 60-90 min in 80 ℃ water bath to obtain mixed solution, filtering to obtain leaching solution rich in lithium salt and leaching residue, carrying out secondary leaching on the leaching residue by using 3-4.5 mol/L phosphoric acid solution, and mixing the leaching solution with the leaching solution rich in lithium salt to obtain lithium-rich leaching solution, wherein the primary leaching solution is mixed solution of phosphoric acid solution, sodium citrate and sodium persulfate; S3, purifying and concentrating the lithium solution, namely purifying and impurity-removing the lithium-rich leaching solution, evaporating and concentrating to obtain concentrated lithium solution which can be used for synthesizing lithium salt, wherein the lithium-rich leaching solution is purified by adding an adsorbent, and the preparation process of the adsorbent is as follows: Mixing ferric trichloride hexahydrate, aluminum trichloride hexahydrate and deionized water in a molar ratio of 3:1 to obtain a mixed solution A, mixing disodium ethylenediamine tetraacetate and sodium hydroxide powder in a molar ratio of 1 (12-15), dissolving the mixed solution A and the mixed solution B in a volume ratio of 1:1 in deionized water to obtain a mixture B, mixing the mixed solution A and the mixed solution B under stirring, aging the mixed solution at a constant temperature of 60-100 ℃ for 12 hours, filtering, washing the mixed solution with deionized water at 60 ℃, and drying the mixed solution to obtain a product A; dispersing the product A in deionized water through ultrasonic assistance, adding sodium alginate, sodium polyacrylate and polyvinyl alcohol, stirring at 400rpm for 60-90 min, molding by using a mold, and performing vacuum freeze drying to obtain the adsorbent.
  2. 2. The process for extracting lithium from lithium battery waste according to claim 1, wherein the concentration of the phosphoric acid solution is 2-4 mol/L.
  3. 3. The process for extracting lithium from lithium battery waste according to claim 1, wherein the mass ratio of sodium citrate, sodium persulfate and pretreatment materials is (0.5-0.8): 1 (5-10).
  4. 4. The process for extracting lithium from lithium battery waste according to claim 1, wherein the ratio of the pretreatment material to the phosphoric acid solution is 1 (20-25) g/mL.
  5. 5. The process for extracting lithium from lithium battery waste according to claim 1, wherein in the step S2, the condition for the secondary leaching is that the secondary leaching is maintained at 60-80 ℃ for 60-90 min.
  6. 6. The process for extracting lithium from lithium battery waste according to claim 1, wherein the adsorbent can be continuously used after being washed by deionized water and dried after being dispersed in 50mL of 0.01mol/L Na-EDTA eluent and being sonicated for 10 min.
  7. 7. The process for extracting lithium from lithium battery waste according to claim 1, wherein the mass ratio of the product A to sodium alginate to sodium polyacrylate to polyvinyl alcohol to deionized water is (0.2-0.5): 1-1.5): 0.1 (0.5-1): 50.

Description

Process for extracting lithium from lithium battery waste Technical Field The invention belongs to the technical field of lithium extraction, and relates to a process for extracting lithium from lithium battery waste. Background At present, the recovery process of the waste lithium ion battery mainly comprises hydrometallurgy, pyrometallurgy and the like. Hydrometallurgy is a method which is researched and applied at present, and is a mainstream because of high recovery rate and good product purity, and the core steps of hydrometallurgy are acid leaching, purifying, extracting and precipitating. However, the conventional hydrometallurgical process still has many challenges in practical application, and in the prior art, particularly in the acid leaching step, a series of problems to be solved are to be solved, such as poor selectivity of the conventional inorganic strong acid (such as sulfuric acid and hydrochloric acid) leaching method, dependence on multi-step solvent extraction or selective precipitation to realize metal separation, and problems of large reagent consumption, high operation cost, large wastewater production amount and the like, and secondary pollution may be caused by the extractant. Therefore, how to avoid the above problems provides a method for obtaining a high lithium recovery rate with a simple process flow, which is a technical problem to be solved by those skilled in the art. Disclosure of Invention The invention aims to provide a process for extracting lithium from lithium battery waste, which can avoid the problems of using inorganic strong acid and poor selectivity, has simple process flow and can obtain high lithium recovery rate. The aim of the invention can be achieved by the following technical scheme: a process for extracting lithium from lithium battery waste, comprising the following steps: S1, pyrolyzing lithium battery waste at 350-400 ℃ in an inert atmosphere for 1-2 hours, and stripping to obtain a pretreatment material; S2, lithium leaching, namely mixing the pretreated material with primary leaching solution, stirring at 200rpm for 60-90 min in an 80 ℃ water bath to obtain mixed solution, filtering to obtain leaching solution rich in lithium salt and leaching residues, carrying out secondary leaching on the leaching residues by using 3-4.5 mol/L phosphoric acid solution, and mixing with the leaching solution rich in lithium salt to obtain lithium-rich leaching solution; s3, purifying and concentrating the lithium solution, namely purifying and removing impurities from the lithium-rich leaching solution, and evaporating and concentrating to obtain concentrated lithium solution which can be used for synthesizing lithium salt. Further, in step S1, the primary leaching solution is a mixed solution of phosphoric acid solution, sodium citrate and sodium persulfate. Further, the concentration of the phosphoric acid solution is 2-4 mol/L. Further, the mass ratio of the sodium citrate, the sodium persulfate and the pretreatment material is (0.5-0.8): 1 (5-10). Further, the ratio of the pretreatment material to the phosphoric acid solution is 1 (20-25) g/mL. Further, in the step S2, the condition of the secondary pickling is that the secondary pickling is kept for 60-90 min at 60-80 ℃. Further, in step S3, the purification and impurity removal process is as follows: And adding NaOH solution or LiOH solution into the lithium-rich leaching solution, regulating the pH value of the solution to 5.0-6.0, adding polyacrylamide accounting for 2% of the mass of the lithium-rich leaching solution, standing for precipitation, performing filter pressing or vacuum suction filtration to obtain clear liquid and filter residues, adding sodium hydroxide solution into the clear liquid continuously to regulate the pH value of the solution to 9-10, standing for precipitation, and filtering to obtain refined lithium solution. Further, in step S3, the lithium-rich leaching solution may be purified by adding an adsorbent, and the preparation process of the adsorbent is as follows: Mixing ferric trichloride hexahydrate, aluminum trichloride hexahydrate and deionized water in a molar ratio of 3:1 to obtain a mixed solution A, mixing disodium ethylenediamine tetraacetate and sodium hydroxide powder in a molar ratio of 1 (12-15), dissolving the mixed solution A and the mixed solution B in a volume ratio of 1:1 in deionized water to obtain a mixture B, mixing the mixed solution A and the mixed solution B under stirring, aging the mixed solution at a constant temperature of 60-100 ℃ for 12 hours, filtering, washing the mixed solution with deionized water at 60 ℃, and drying the mixed solution to obtain a product A; Dispersing the product A in deionized water by ultrasonic assistance, adding sodium polyacrylate and polyvinyl alcohol, stirring at 400rpm for 60-90 min, molding by a mold, and performing vacuum freeze drying to obtain the adsorbent. Further, after the adsorbent is used, the adsorbent can be c