A novel approach for the recovery and cyclic utilization of valuable metals by co-smelting spent lithium-ion batteries with copper slag

Achieving efficient and low-cost recycling of spent lithium-ion batteries (LIBs) is of great significance to the sustainable development of the clean energy industry and energy metal resources. This study developed a co-smelting process for the simultaneous recovery of valuable metals from spent LIBs and copper slag by using copper slag as the only flux, CaCl2 as the chlorine donor, and anode graphite and aluminium foil in spent LIBs as reductants. Co, Cu, Ni and Fe from spent LIBs and copper slag are recovered in the form of alloys. The Li is transferred from the slag to the gas phase through the chlorination reaction, which efficiently separates and enriches Li during the co-smelting process. Under the optimized conditions, the recoveries of Co, Cu, Ni and Fe were 99.13 %, 98.04 %, 99.30 % and 97.98 %, respectively, and the Li volatilization rate was 97.86 %. The influences of the processing parameters on the metal recovery and Li volatilization rate were assessed. The reaction mechanism was elucidated based on thermodynamics and phase transitions. In addition, a strategy for the preparation of high value-added products from the smelted products was provided. Lithium-containing dust can be used to prepare battery grade Li2CO3, and smelting slag can be used to prepare glass ceramics. The proposed co-smelting process is feasible for the comprehensive recovery of valuable metals from spent LIBs and copper slag, and thus, it has good application prospects and advantages. Meanwhile, the problem of difficulty in lithium recovery in the traditional process is solved.