Direct sulfation of chalcopyrite with steam and oxygen

A process based on the direct sulphation of chalcopyrite followed by water leaching may be considered an attractive route for the treatment of lean-grade/pocket or complex deposits. A study was made of the sulphation of chalcopyrite in the presence of steam and oxygen, a treatment that is analogous to creating weathering conditions at high temperature. Various parameters, such as the flow rate of oxygen and steam, temperature and time of reaction, as well as the addition of a catalyst, were investigated. It was found that the formation of SO2 and CuO increased with increase in partial pressure of oxygen when no steam was used. However, higher levels of copper sulphate formation were observed with a mixture of steam and oxygen than when oxygen was used alone in the temperature range 673-873K. The presence of ferric oxide as a catalyst during sulphation with steam and oxygen helped to optimize conversion to copper sulphate. A recovery of 82.32% as copper sulphate and 7.5% as copper oxide was attained, giving a total recovery of 89.82% at 773K in the presence of the catalyst.