Effect of collectors, conditioning pH and gases in the separation of sphalerite from pyrite

The effect of collectors, conditioning pH and gases on the selective flotation of sphalerite from pyrite in the presence of Cu(II) has been investigated. In the presence of ethyl xanthate, separation between the two sulfide minerals is only achieved at high pH values. Ethoxycarbonyl thionocarbamate and thiourea are as powerful collectors as xanthate for the flotation of copper-activated sphalerite but they are more selective collectors than xanthate against pyrite at alkaline pH values and especially at more neutral pH values. Selectivity is improved when oxygen is used as the conditioning gas. A copper-collector complex is formed at the surface of both sphalerite and pyrite and its concentration reflects the flotation results.