Abstract:Selective recovery of lithium from cathode materials of spent ternary lithium battery was realized by combining low-temperature potassium pyrosulphate roasting with salt solution leaching. Effects of roasting temperature, mass ratio of potassium pyrosulphate to cathode material, and roasting time on recovery of lithium, cobalt, nickel and manganese were systematically studied. The results show that recovery of Li, Ni, Co and Mn is 97.21%, 2.61%, 3.1% and 10.8%, respectively after leaching with potassium oxalate solution under the conditions including roasting temperature of 350 ℃, mass ratio of cathode material to potassium pyrosulfate of 1︰2, and roasting time of 60 min. At the same time, XRD, SEM and EDS were used to characterize crystal structure, surface morphology and elemental composition changes of the materials before and after roasting. Phase transformation mechanism of lithium, cobalt, nickel and manganese during calcination process of potassium pyrosulphate is further clarified. Compared with traditional wet process, pyrogenic process and biological metallurgy process, this recovery technology has the characteristics of low energy consumption and high application prospect.