1. State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China
2. College of Science, Lanzhou University of Technology, Lanzhou 730050, China
In recent years, the ternary cathode material LiNi0.6Co0.2Mn0.2O2 (NCM622) with high nickel content has been industrialized in high energy density new energy vehicle batteries due to its excellent reversible capacity and chemical stability. In view of the efficient recovery of valuable metals Li, Ni, Co, Mn in the cathode material NCM622 of retired power batteries for new energy vehicles, this paper proposes a new process that uses NCM622 and potassium bisulfate (KHSO4) to mix and roast, and then water leaching to extract metal elements from the spent lithium ion power batteries. The research results show that after the mixture of NCM622 and KHSO4 is roasted at 600 ℃ for 0.5 hours, Li, Ni, Co, and Mn elements are no longer exist in the form of LiNi0.6Co0.2Mn0.2O2, but transformed into LiKSO4, and the oxide or sulfate forms of Ni, Co, and Mn. Ni, Co, and Mn elements in the calcined products tend to exist in low valence states. When the mixed mass ratio of NCM622 and KHSO4 is 1∶4.63, the extraction rates of Li, Ni, Co, and Mn elements are 99.93%, 97.97%, 98.36%, and 97.13% after roasting and water leaching,respectively.