Extraction of organic solvents and preferential recovery of lithium from spent lithium-ion batteries by in-situ carbothermal reduction

Abstract

The sorting of spent lithium-ion batteries is not complete, and the types of black powder obtained by crushing are complex, and it is difficult to recycle. In this study, dimethyl carbonate was used to extract the organic solvent cured in the black powder, and then the carbon in the black powder was combined with complex sulfate for in-situ thermal reduction and water leaching to extract Li preferentially from the black powder. The effects of extraction factors on the recovery of organic solvents and the variables on the preferential leaching of Li were systematically studied. The changes of mineral phase during roasting were analyzed by TG-DTG, XRD, XPS and SEM-EDS. After black powder was roasted at 550°C for 3 h under air atmosphere with the synergistic effect of C and inorganic salts, 85.87 % of lithium can be selectively leached at 25°C for 2 h. Li₂CO₃ with high purity can be obtained. This method provides a new idea for the recovery of spent lithium-ion batteries with complex components.