Mechanisms and Application of MFD Catalyst on the Leaching of Secondary Copper Sulfide
Cu and Ni minerals that have great economic value mostly exist in the form of sulfides, making them difficult to extract using hydrometallurgical processes. Currently, heap leaching is the most economical way to extract these metals from low grade ores. Copper recoveries of many chalcocite heap leaches report around 70% copper recovery. However, the chalcocite leaching reaction has several stages. The first stage leach is characterized by 50% copper extraction and the conversion of chalcocite into a second stage of covellite (CuS) which is very difficult to leach at ambient temperature. In our preliminary test using acidic ferric sulfate as lixivant, addition of MFD catalyst increased the rate of chalcocite leaching by 5 times in the first 8 hours of reaction in stirred reactors. A similar test using a stirred reactor was also performed on pure covellite, improving its leaching rate by 36 times in the first 8 hours. Therefore, there will be imminent application for MFD catalyst in heap and dump leaching of copper sulfides.