Method for preparing battery-grade lithium carbonate from waste lithium batteries

By combining the choline chloride-citric acid low eutectic solvent and activated carbon, the problems of low lithium ion recovery rate and low lithium carbonate purity in lithium iron phosphate batteries were solved, an efficient and simplified lithium ion recovery and purification process was achieved, and high-purity lithium carbonate was prepared.

CN120757132APending Publication Date: 2025-10-10JIANGSU UNIV OF TECH
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Patent Information

Application Number
CN202510994354.0
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2025-07-18
Publication Date
2025-10-10

AI Technical Summary

Technical Problem

In the existing technology, the lithium ion recovery rate in lithium iron phosphate batteries is low, the process is complicated, the lithium carbonate purity is low, the crystal particle size is large, the particle size is uneven, and there are many impurities, which leads to resource waste and environmental pollution.

Method used

A choline chloride-citric acid low eutectic solvent system is used to accelerate lithium ion leaching by selectively complexing lithium ions and adding a polymer catalyst. Combined with deep impurity removal using activated carbon, gradient cooling crystallization and three-stage purification and beating processes are used to control crystallization kinetics and improve lithium ion recovery rate and purity.

Benefits of technology

The recovery rate and purity of lithium ions are significantly improved, the impurity content is reduced, the preparation of high-purity battery-grade lithium carbonate is achieved, the process flow is simplified and the preparation time is shortened.

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Abstract

The invention relates to the technical field of lithium battery materials, in particular to a method for preparing battery-grade lithium carbonate from waste lithium batteries. The method comprises the following steps: disassembling, crushing and sieving a recycled lithium iron phosphate battery to obtain a crushed lithium battery material; a choline chloride-citric acid mixed solution is adopted to conduct leaching treatment on the crushed materials, and sulfuric acid is added to inhibit leaching of iron and phosphorus ions; filtering to obtain a first filtrate and a first filter residue; adding calcium hydroxide into the first filtrate, and filtering to obtain second filtrate and second filter residues; adsorbing the second filtrate with activated carbon to remove impurities, and filtering to obtain a third filtrate and a third filter residue; adding hydrochloric acid into the third filtrate to obtain a lithium chloride solution; carbonizing and converting the lithium chloride solution into a lithium carbonate solution; and carrying out gradient crystallization treatment on the lithium carbonate solution, pulping with pure water, and drying to obtain the high-purity lithium carbonate finished product. The method overcomes the problems of low lithium recovery rate, complex process, low lithium carbonate purity, large crystal particle size, more impurities and the like of the existing lithium iron phosphate battery.
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