Effect of Aqueous Ferrous Ion on Collectorless Flotation of Pyrite

The presence of pyrite in the mineral concentrates of the base metals obtained during flotation is a common problem; the depression of these impurities continues under investigation. This paper analyzes the surface state by FTIR of pyrite obtained during collectorless flotation using several concentrations of ferrous sulfate (FS) as a depressant. The results found show that the presence of 300 mg/L Fe2+ at pH 6 depresses the pyrite, obtaining a 25% (w/w) cumulative flotation, at pulp potentials of + 300 mV, while in the absence of FS it is 89.9% (w/w). for all the concentrations analyzed (100, 160, 240 and 300 mg/L) the pyrite flotation is less than 50%, the pyrite surfaces characterized by FTIR indicate the presence of different species of iron oxides such as akaganeite, lepidocrocite, schwertmanite as well as the presence free sulfate ion responsible for the pyrite depression.