Abstract:The harmless treatment and resource recycling of spent lithium-ion batteries is an inevitable choice to protect the environment, save resources, and promote the development of circular economy. A process of sodium salt roasting and water leaching at room temperature was proposed to recover lithium from spent LiFePO4 batteries. The effects of sodium sulfate addition, roasting temperature, and roasting time on the selective leaching of lithium were systematically studied, and the roasted products were characterized by XRD and SEM. The results show that under the conditions of mass ratio of sodium sulfate to LiFePO4 cathode powder of 1.6, roasting temperature of 650 ℃, water leaching time of 15 minutes, and roasting time of two hours, the lithium leaching rate is 96.81%, and the purity of the recovered lithium sulfate product is 97.36%. Compared with traditional methods, this process has the advantages of no use of strong acid, high efficiency separation of lithium iron and simple recovery process, and has broad industrial application prospects.