Solving the mystery of natural pyrite flotation – A mineralogy-based approach

Many different types of pyrite have been observed in the mineral processing industry, varying in texture, chemical composition, electrochemical properties, and flotation response. One particular type of pyrite has been noted for its unusual behaviour is framboidal or “carbonaceous” pyrite. Specifically, a long history of carbonaceous pyrite presence has been recorded and studied at Glencore's Mount Isa Mines. This work is a detailed examination of the mineralogical characteristics of ore samples containing different pyrite types, to determine the underlying drivers of natural pyrite flotation. The work also revisits the original hypothesis that pyrite floatability is facilitated by the presence of carbonaceous material within the mineral matrix. Overall, this work closely mirrored that of previous studies, with the results closely aligned. The main difference is that when multiple ore domains are subjected to the same analysis, the flotation behaviour of carbonaceous content and pyrite appear to be independent. Instead, excessive natural flotation recoveries of pyrite are likely to be driven by factors that include the effect of galvanic interactions between chalcopyrite and pyrite.