Hydrochloric acid leaching mechanism of recycling cobalt and copper material from lithium-ion battery

The materials recycled from the roasted spent lithium-ion batteries were analyzed by chemical phase and SEM micrograph,and the hydrochloric acid leaching mechanism was studied by thermodynamics principium,and validated by the experiments.The results show that this material contains high-grade cobalt and copper existing as metal and different valence state oxides.Besides CoO,Co and CuO can dissolve in acid easily,Co has a priority for substitutional deposits of Cu2+;Co3O4 and Co2O3 can be reductively leached by HCl;Cu2O may occur a disproportionating reaction;Cu can be leached finally by chlorination;parts of Cu have a course of dissolution-cementation-redissolution in leaching system.The thermodynamic study indicates that the method is feasible,and the interaction of cobalt and copper component in the leaching system is propitious to increasing the leaching efficiency.HCl leaching experiments support the conclusions,and the leaching efficiency of cobalt and copper can reach 99.3% and 95.9% respectively when leaching at 318 K with 2 mol/L HCl for 6 h,and volume mass ratio of liquid to solid(20 ∶1) mL/g,stirring speed at 200 r/min.