Floc flotation of galena and sphalerite fines

The flotation of galena and sphalerite fines in the form of flocs, which is termed floc flotation, has been studied in the present work. The flocs formed through hydrophobic flocculation induced by potassium amyl xanthate (PAX) and kinetic energy input. The studies were performed on single minerals of −20 μm size by using micro-flotation and floc size measurements. Several parameters, including pH, PAX concentration, kerosene addition and stirring strength, have been investigated for their effects on the floc flotation. The results show that the floc flotation closely correlates with the size of flocs. At good operating conditions, the floc flotation of galena and sphalerite fines can reach floatability of 100%, in comparison to conventional flotation obtaining floatability of about 40%. It has been found that a small addition of kerosene greatly improved the floc flotation, saving a large amount of PAX. Also, the floc flotation was tested on the Rey de Plata ore of Guerrero of Mexico, in which some of the metallic (Pb, Zn, Ag, Au, Cu) sulfide minerals are finely disseminated. The beneficiation results have demonstrated that floc flotation not only reduces the losses of the valuable metals in tailing, but also greatly increases the separation efficiency at cleaner flotation steps, producing concentrates with much higher grade and recovery in comparison to conventional flotation. The former effect might be due to the increase in recovery of the valuable minerals fines, and the latter might be attributed to the increase of the flotation rate of valuable mineral, because of floc formation and kerosene addition.