Dissolution kinetics of zinc and indium from high iron-bearing zinc calcine in sulfuric acid solution

A sulfuric acid-based process was proposed for the extraction of zinc and indium from a sample of high iron-bearing zinc calcine. The influence of initial concentration of acid solution, reaction time, liquid-to-solid ratio, and leaching temperature on the extents of Zn, In and Fe were comprehensively investigated. The preferred experimental conditions were the initial concentration of acid solution 180 g·L⁻¹, a reaction time 1 h, a leaching temperature 80℃, and a liquid-to-solid ratio (L/S) 5:1, in which the highest leaching extents of Zn, In and Fe were up to 82.92%, 25.64%, and 9.75%, respectively. Finally, the dissolution kinetics of zinc and indium from zinc calcine were investigated in detail resulting in obtaining apparent activation energies for their respective leaching process as 20.12 kJ·mol⁻¹ for zinc and 7.85 kJ·mol⁻¹ for indium, and the semi-empirical kinetic equations of zinc and indium were also established.