The role of pulp potential and the sulphidization technique in the recovery of sulphide and oxide copper minerals from a complex ore

Kansanshi copper mine is situated in the northwestern province of Zambia. Weathering has given rise to a vertically zoned profile comprising leached, refractory, oxide, mixed, and hypogene sulphide mineralization. As a result of the mineral variations, the processing plant treats three distinct ore types, viz. oxide, sulphide, and mixed. The objective of this study was to investigate the floatability of a complex Kansanshi mixed copper ore comprising sulphide and oxide minerals, with a view to achieving an optimal flotation performance in the treatment of the Kansanshi orebody, with a special focus on the sulphidization process. This required an in-depth analysis of the mineralogy of the feed as well as tailings samples after different flotation processes involving a range of reagent types and dosage procedures. Controlled potential sulphidization (CPS) has been adopted over slug sulphidization as the industry standard for the recovery of oxide copper minerals through flotation. Two potential ranges were investigated in this study; -300 to -400 mV and -400 to -500 mV. Optimum flotation performance was observed in the potential range of -300 to -400 mV and a NaHS: SIBX ratio of 7: 1 during CPS. CPS was also found to be economically superior to slug addition.