Abstract
A comparative study of chemical and electrochemical leaching of a sintered disk of CuS was carried out at 343 to elucidate the leaching mechanism of CuS with FeCl3. The leaching,rate of CuS exhibited a half order dependence on the FeCl3 concentration, but the addition of FeCl2 slightly reduced the leaching rate. The mixed potential of CuS exhibited a 53 mV decade-1 dependence upon the FeCl3 concentration; no significant effect on the mixed potential was observed by the addition of FeCl2. Based on these observations, an electrochemical mechanism is proposed which involves the oxidation of CuS and the reduction of FeCl2 + . The activation energy in chemical leaching of CuS was 46.7 kJ mol-1, while in electrochemical leaching, it was 50.4 kJ mol-1. By converting the leaching rate to electric current density,i, a 110 mV decade-1 dependence of mixed potential, E, against log i is obtained. This dependence of the mixed potential during chemical leaching of CuS on FeCl3 concentration agrees with the value theoretically expected from the electrochemical model of the leaching process. These findings strongly support an electrochemical mechanism for the FeCl3 leaching of CuS.
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HIROSHI HIAI, formerly Graduate Student with Kyoto University
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Hirato, T., Hiai, H., Awakura, Y. et al. The leaching of sintered CuS disks with ferric chlorides. Metall Trans B 20, 485–491 (1989). https://doi.org/10.1007/BF02654597
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DOI: https://doi.org/10.1007/BF02654597