Electrochemical investigation on collectorless flotation of sphalerite in presence of Cu2+ ions

The collectorless flotation behaviors of sphalerite in the presence of Cu2+ ions have been established. The effects of pH, potential and Cu2+ concentration on the flotation have been studied using a micro-flotation cell specially designed, where the potential can be controlled by a potentiostat. The flotation results have shown that the Cu-activated sphalerite displays a good collectorless floatability in a pH range of 0 similar to 13. The higher potentials can improve the flotation recovery. The surface species formed during the Cu ion activation have been examined using a special electrochemical technique-a composite sphalerite electrode. Zinc-deficient sulfide (Zn1-xCuxS) and Cu-poly sulfide (Cuy+zSy) species have been determined. They are responsible for the collectorless flotation of sphalerite. In additional, they can improve the conductivity of the sphalerite surface.