THE INTERACTION OF IRON SPECIES WITH PYRITE SURFACES

The development of iron oxide films on pyrite has been investigated using linear potential sweep voltammetry. Voltammograms for a fresh pyrite surface indicated the presence of an iron (II) hydroxy-oxide. After brief exposure to air, the surface layer oxidized to iron(III) hydroxy-oxide. Immersion in iron(II) solutions containing small amounts of iron(III) resulted in an increase in the thickness of the oxide layer to a limiting value; the oxide was present mainly in the iron(III) state. An iron hydroxy-oxide also developed on gold during immersion in iron(II) solution. A pyrite surface abraded on iron powder in deoxygenated water also became coated with iron hydroxy-oxide. Immersion of pyrite in cyanide solution resulted in a decrease in the quantity of oxide on the surface.