An electrochemical investigation on collectorless flotation of sphalerite in presence of Cu2+ ions

The collectorless flotation behaviors of sphalerite in the presence of Cu 2+ ions have been established. The effects of pH, potential and Cu 2+ 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 0～13. 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 (Zn 1- x Cu x S) and Cu poly sulfide (Cu y+z S y ) species have been determined. They are responsible for the collectorless flotation of sphalerite. In additional, they can improve the conductivity of the sphalerite surface.