Selective recovery of lithium from spent lithium iron phosphate batteries using oxidation pressure sulfuric acid leaching system
(1. Institute of Resource Utilization and Rare Earth Development, Guangdong Academy of Sciences, Guangzhou 510650, China;
2. State Key Laboratory of Separation and Comprehensive Utilization of Rare Metals, Guangzhou 510650, China;
3. Guangdong Provincial Key Laboratory of Rare Earth Development and Application, Guangzhou 510650, China;
4. Guangdong Brunp Recycling Technology Co., Ltd., Foshan 528100, China)
2. State Key Laboratory of Separation and Comprehensive Utilization of Rare Metals, Guangzhou 510650, China;
3. Guangdong Provincial Key Laboratory of Rare Earth Development and Application, Guangzhou 510650, China;
4. Guangdong Brunp Recycling Technology Co., Ltd., Foshan 528100, China)
Abstract: Oxidation pressure leaching was proposed to selectively dissolve Li from spent LiFePO4 batteries in a stoichiometric sulfuric acid solution. Using O2 as an oxidant and stoichiometric sulfuric acid as leaching agent, above 97% of Li was leached into the solution, whereas more than 99% of Fe remained in the leaching residue, enabling a relatively low cost for one-step separation of Li and Fe. And then, by adjusting the pH of leachate, above 95% of Li was recovered in the form of the Li3PO4 product through iron removal and chemical precipitation of phosphate.
Key words: spent LiFePO4 batteries; oxidation pressure leaching; separation; Li; Fe; lithium phosphate