ABSTRACT
The present study aims to investigate the influence of the pulp chemistry on the collectorless flotation of chalcopyrite and galena. Experimental findings revealed that chalcopyrite exhibited significant collectorless flotation at pH 10 and pulp potentials between +100 mV and + 120 mV. Raman spectroscopy confirmed the formation of the mixed metal polysulphides on the surface of chalcopyrite floated with no additions. This might be attributed to the importance of these species in the collectorless flotation of chalcopyrite. The pulp potentials below 100 mV and above 120 mV obtained by the use of oxidizing and reducing agents such as sodium metabisulphite and ferric nitrate depressed the flotation significantly. Galena showed good floatability at pH 8 and pulp potentials between + 190 mV and +230 mV. At pH 8 addition of ferric nitrate depressed the flotation of galena.
