Structural and temperature sensitivity of leaching of chalcopyrite with iron(III) sulphate

Abstract

In this study, the leaching of chalcopyrite with acid solution of iron (III) sulphate was investigated. It has been found that the rate of leaching may be favourably influenced by mechanical activation of CuFeS 2. The linear relationship between the initial rate constant of leaching k o and the ratio S/ X describes the joint influence on reaction rate of the increase in surface S and of the decrease in content of the crystalline phase X due to mechanical activation and represents the evidence of structural sensitivity of the reaction. The investigation of temperature dependence of reaction (1) for mechanically activated chalcopyrite in the temperature region 333–368 K discloses a change in mechanism of the reaction at 363 K. It can be assumed that the mechanical activation influences the self-diffusion of the ions of copper and iron. Its acceleration by mechanical activation results in the fact that the chemical reaction gradually assumes the function of the rate determining stage. However, the increasing thickness of elemental sulphur on the surface of the non-consumed CuFeS 2 enhances the retarding effect of this solid product.