Studies on the kinetics of zinc and indium extraction from indium-bearing zinc ferrite

The leaching kinetics of extracting zinc and indium from synthetic indium-bearing zinc ferrite (IBZF) was studied and the influence of stirring, particle size, reaction temperature and sulphuric acid concentration were investigated. The results showed that the apparent particle size had no significant effect on the dissolution of the IBZF, but an increase in temperature, sulphuric acid concentration significantly enhanced the leaching efficiencies of zinc and indium. Sharp's method of half time of reaction was used for the determination of kinetic parameters and the rate controlling step. It was found that the empirical kinetic model, − ln(1 − α) = kt applied well to the kinetics analysis and that both zinc and indium leaching were similar and controlled by chemical reaction with activation energies of 76.4 kJ/mol and 68.8 kJ/mol, respectively. The reaction orders with respect to sulphuric acid concentration were 0.79 for zinc leaching and 0.69 for indium leaching.