China Nonferrous Metallurgy

Aiming at the problems of high acid consumption and high energy consumption in the current process of recycling waste lithium ion batteries, this paper conducted a nickel cobalt manganese leaching test with waste 523 nickel cobalt manganese cathode material after electrolysis as raw material and sulfuric acid + hydroxylamine hydrochloride as the leaching agent. The influence of each process condition on the leaching rate was investigated, and the positive electrode material before and after leaching was characterized and analyzed. The kinetics analysis of the leaching process was also carried out, and the following main conclusions were obtained. The optimal leaching conditions of the system were as follows: hydroxylamine hydrochloride concentration 1.5mol/L, sulfuric acid concentration 1mol/L, leaching temperature 75℃, liquid-solid ratio 25mL/g, leaching time 60min. The leaching rates of nickel, cobalt and manganese were 96.84%, 99.87% and 97.35%, respectively. XRD analysis shows that there is almost no peak after leaching, and only weak peak shift of NiO and MnO2. SEM analysis shows that the positive electrode material presents small pieces of broken powder after leaching, indicating that the valuable metal in it has been leached. The study of leaching kinetics showed that the leaching process in this experiment was suitable for fitting by Avrami equation. The activation energies of nickel, cobalt and manganese were 8.3779kJ/mol, 4.6836kJ/mol and 4.9614kJ/mol, respectively. The leaching temperature had little effect on the reaction rate constant, and the leaching process was controlled by diffusion conditions. The results of this study provide an effective wet leaching process for the recovery of waste lithium-ion batteries, and provide a reference for theoretical research and application in related fields.