Dissolution kinetics of sphalerite with hydrogen peroxide in sulphuric acid medium

The kinetics of dissolution of sphalerite with hydrogen peroxide in sulphuric acid solution was investigated. The influence of stirring speed (0–600 rpm), dissolution temperature (10–60 °C), sulphuric acid concentration (0.5–6.0 M), hydrogen peroxide concentration (0.1–6 M), and particle size were studied. The dissolution kinetics was found to follow a shrinking-core model, with the surface chemical reaction as the rate-determining step. This finding is in concordance with the activation energy of 43 kJ/mol and a linear relationship between the rate constant and the reciprocal of particle size. Increasing concentrations of sulphuric acid and hydrogen peroxide have a positive effect on the dissolution of sphalerite, and orders of reaction of 0.35 and 0.48 were established with respect to sulphuric acid and hydrogen peroxide concentrations, respectively. Stirring speed had no effect on the rate of sphalerite dissolution.