Leaching of Valuable Metals from Calcined Spent Lithium-ion Batteries

Leaching behavior of valuable metal elements in roasted spent lithium-ion batteries was investigated.The pulp of LiCoO2 or Co3O4 mixed with concentrated sulfuric acid and one of sodium sulfate,potassium sulfate and ammonium sulfate was heated in the temperature range from 150 ℃ to 300 ℃.The cobalt-containing transformation products were then subject to dissolution in hot water.The dissolution rate of transformation products of LiCoO2-containing pulp was 56.4%～100%,and that of Co3O4-containing pulp 97.2%～100%.M2Co(SO4)2·nH2O(M=Na,K,NH4+) phases formed in the transformation products with sodium sulfate,which were easily dissolved in hot water.Moreover,the mixture of roasted residue of spent lithium-ion batteries with concentrated sulfuric acid and sodium sulfate was heated at 400℃.All of the Li and Co elements in the mixture were leached out in hot water at 70℃,and the leaching rates of Cu and Al were greater than 99%.