Electrochemical measurements using a chalcopyrite electrode, coupled with chemical leaching experiments, were used to study the interactions between chalcopyrite leaching, temperature, Fe in solution and surface modifications. Leaching of chalcopyrite presented two-stage kinetics: an induction period and a linear kinetics. The induction period decreased with increasing temperature. It was found that chalcopyrite dissolution was accelerated at high temperature and low potentials. The results showed that chalcopyrite passivation can be explained by two different mechanisms. At low temperature and low potentials the leaching rate seems to be retarded by the formation of a copper-rich polysulphide. A ratio of dissolved copper to iron of 1:3 was obtained at a constant potential of 0.450 V vs SCE. The leaching rate also decreases at high temperature and high potentials, possibly due to the precipitation of ferric ions that hydrolyze to form iron-hydroxy compounds. There was a good agreement between electrochemical data and the results of chemical leaching tests.
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