China Nonferrous Metallurgy

The leaching and leaching kinetics of Cobalt in lowgrade copper ores of Africa were studied and the mechanism of reduction leaching of associated cobalt was discussed from the perspective of thermodynamics. The results show that increasing the amount of reducing agent, sulfuric acid, leaching temperature and liquidsolid ratio can improve the leaching rate of cobalt, and speedup the process of leaching. The leaching equilibrium of cobalt can be achieved in about 1hour. The dissolution behavior of cobalt in lowgrade copper ores coincides with the mixed kineticshrinking core model, which is based on the interface transfer and diffusion across the solid layers. The activation energy is determined to be 13.42kJ/mol and the kinetic equation can be expressed as follows: 13ln(1-x)+(1-x)-13-1=0.0025m0.8688r0.1974N1.0147e-13.42RTt. It provides a theoretical basis for improving the leaching rate of associated cobalt in practical production.