In recent times, attention has been drawn to low-grade complex sulphide ores due to the decline in the world deposits of high-grade ores. Complex sulphide ores are in many cases difficult to treat with conventional mineral processing methods and the concentrates produced are often not clean enough. This seriously limits their commercial value (Ortega and Bonilla, 1983). Differential flotation does not release all the constituents' phases (Majima, 1969) and so the different concentrates obtained are of poor quality with a low metal recovery. This makes further pyrometal-lurgical processing of these ores very difficult and costly (Rubio and Frutos, 2002) and renders them difficult to commercialize (Sandstrom and Peterson, 1997). As a result, the metal value is preferably extracted directly from the low-grade ores through a hydromet-allurgical process. However, sulphide ores do not allow the recovery of metal by direct chemical leaching (Hiskey and Wadsworth, 1975; Dutrizac, 1989), due to their low solubility in most leaching reagents.
展开▼
