MODELLING CHALCOPYRITE LEACHING BY Fe+3 IONS WITH THE SHRINKING CORE MODEL

Abstract

Chalcopyrite leaching by ferric iron is considered a slow process with low copper recovery; a phenomenon ascribed to the passivation of the mineral surface during leaching. Thus, the current study investigated the leaching kinetics of a high purity chalcopyrite sample in the presence of ferric sulfate as oxidant. The effects of the stirring rate, temperature, Eh and Fe3+ concentration on copper extraction were assessed. The leaching data could be described by the shirking core model (SCM) for particles of unchanging size and indicated diffusion in the ash layer as the rate-controlling step with a high activation energy (103.9±6.5kJ/mol); likely an outcome of neglecting the effect of particle size distribution (PSD) on the kinetics equations. Both the application of the quasi-steady-state assumption to solid-liquid systems and the effect of the particle size distribution on the interpretation of kinetics data are also discussed.

Keywords

• Chalcopyrite; Shrinking core model; Activation energy.