Comprehensive Leaching Kinetics by Sulfuric Acid from Zinc Hydrometallurgy Residue

A study on the kinetics of leaching copper-cadmium slag was carried out.The effects of acidity,solid/liquid ratio,reaction temperature,leaching time on the comprehensive leaching ratio were determined.Under the optimal conditions,the comprehensive leaching ratio is more than 89%.The leaching reaction is a typical oxido-reduction,and the results show that the leaching process can be simulated with a shrinking core model.The leaching ratio is controlled by the diffusion of reacting reagents in a porous solid layer.An empirical equation for the leaching kinetics is established,which expressed by equation 1-23η-(1-η)~(23)=k_et.It provides the theoretical basis for leaching copper-cadmium slag with high performance and low consumption.The activation energy is 8.193 kJ/mol calculated according to the Arrhenius equation.