Preparation of high grade industrial copper compound from a Nigerian malachite mineral by hydrometallurgical process

Abstract

Increasing demands for copper and copper sulphate with diverse industrial applications has prompted the development of a low-cost and eco-friendly technique as a substitute for conventional ore treatments by reduction-roasting route, requiring high energy consumption. In this study, hydrometallurgical treatment of a Nigerian malachite through acid leaching and solvent extraction was investigated. The effects of leachant concentration, reaction temperature and particle size were examined. The rate of ore dissolution increased with increasing H2SO4 concentration, temperature and decreasing particle size. At optimal leaching conditions, 96.2% of the ore reacted with 2.0 mol/L H2SO4 solution at 75 °C within 120 min. The calculated activation energy was 25.41 kJ/mol, supporting the proposed diffusion controlled mechanism for the dissolution process. The leach liquor at optimal conditions was further beneficiated to obtain high grade industrial copper sulphate using a combinations of solvent extraction and precipitation methods, leading to 98% process efficiency.