Study of Cadmium Ions Cementation with Zinc Powder from High-Cadmium-concentration Zinc Sulphate Solutions

The recovery of metals from industrial and metallurgical effluents is crucial to minimise the environmental and economic impacts associated with the generation and disposal of these solutions. Therefore, this study uses zinc powder for the cementation of cadmium from a high-cadmium-concentration zinc sulphate solution. This study investigates the dependence of cadmium removal efficiency on the initial copper concentration, solution pH, stoichiometric ratio of added zinc, temperature, particle size, zinc powder activation and mode of zinc addition. The results show the possibility of achieving a cadmium removal efficiency 90-95% under optimal conditions. The reaction kinetics calculations revealed an activation energy of 11.89 kJ mol(-1), indicating a diffusion-controlled reaction mechanism and the possibility to reduce the limitations of the controlling step by increasing the stirring rate during the cementation process. These observations provide further understanding and guidance toward the efficient utilisation of cadmium cementation to prepare sponge cadmium in zinc hydrometallurgy.