Flotation of heavily oxidized pyrite in the presence of fine digenite particles

The ease or complexity of the selective separation of copper sulphur minerals during sulphide flotation is always dominated by the level of surface oxidation. The interaction between oxidized pyrite and other base metal sulphides is important for the flotation process. In this study, the effects of fine digenite particles on the flotation of heavily oxidized pyrite in the presence of sodium butyl xanthate were investigated. The micro-flotation results showed that the floatability of pyrite declined sharply once it was over-oxidized. However, the addition of fine digenite significantly restored the floatability and flotation rate of pyrite, even in strong alkaline solutions. Scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) of the flotation products indicated no copper ions on the pyrite surface. This restoration can be attributed to fine digenite particles adsorbing on the surface of coarse pyrite particles and removing a large number of fine pyrite particles covering the pyrite surface in the presence of sodium butyl xanthate. The extended Derjaguin-Landau-Verwey-Overbeek theory based on zeta potential measurements and contact angle measurements was used to calculate the interaction energy between mineral particles. The calculation results showed good agreement with the flotation and SEM-EDS analysis results and explained the mechanism of particle interaction.