A New Approach to Lithium Resource Acquisition by Recovering Lithium from Sludge Generated during the Production of Lithium Iron Phosphate Batteries

Lithium is an important alkalinous metal with a wide range of usage and high economic value. With the transformation of the global energy structure and the rapid development of a new energy industry, the demand for lithium is increasing. Therefore, it is of great strategic significance and economic value to find new ways to obtain lithium resources. The total amount of secondary lithium resources is abundant, but the current research mainly focuses on lithium extraction from waste lithium-ion batteries (LIBs), rather than the waste resources generated during LIB production. Therefore, in this study, the sludge generated during the production of lithium iron phosphate batteries (LiFePO4, LFP) is used as a raw material to extract lithium using the leaching system of H2SO4–H2O2, and factors that impact the leaching efficiency are discussed. The results show that the leaching efficiency of lithium could reach 99.32% under optimal experimental conditions. Thermodynamic and kinetic analyses indicate that lithium sludge leaching by sulfuric acid can occur spontaneously at room temperature, and the leaching process is controlled by a combination of chemical reaction and diffusion. The research results provide a new approach for lithium supply, showing a good perspective.