Abstract
— Chalcopyrite (CuFeS2) is the primary source of global copper supply, yet its extraction remains challenging due to passivation layers that form during the leaching process. This study investigated the combined effects of oxidative roasting and galvanic coupling with manganese dioxide (MnO2) on copper recovery from a chalcopyrite concentrate with a head grade of 26.26% Cu. Samples of the concentrate were roasted at temperatures of 400°C, 600°C, and 900°C for one hour, the leaching of the roasted samples using a 0.03M sulfuric acid with and without MnO2, at temperature ranges from 25°C to 55° for 8 hours. XRF, XRD, and SEM-EDS were used to analyse the phase transformations of the concentrate throughout the whole roasting process. Results showed that unroasted chalcopyrite yielded only 15% copper recovery with sulfuric acid alone but improved to above 60% with the addition of MnO2. Roasting at 600°C produced the best results, achieving a recovery of 85% with only sulfuric acid and exceeded 90% when combined with MnO2, reaching 95%. However, roasting at 900°C reduced copper recovery to 60%. Kinetic analysis revealed that the leaching process follows a diffusion-controlled shrinking core model with low activation energy. Overall, this study revealed that for effective copper recovery, and approach of combining both roasting and galvanic coupling is the best approach.