Abstract: In order to clarify the oxidation law of pyrite under natural conditions and the effect of surface oxidation of pyrite on flotation. The effect of oxidation time on the floatability of pyrite single mineral under natural oxidation conditions was studied. The recovery of pyrite decreased with the increase of oxidation time. The results of X-ray photoelectron spectroscopy (XPS) show that there are new characteristic peaks of sulfur， ferric sulfate and ferric hydroxide on the surface of oxidized pyrite， and the oxidation of pyrite terminated when ferric hydroxide covered its surface. During the flotation process， hydrophilic substances such as iron hydroxide formed on the surface of oxidized pyrite and changed the surface properties of pyrite， hindered the adsorption of collectors and reduced the floatability of pyrite. The results provide some references for the flotation separation of precious metal from pyrite by decrease the floatability of pyrite.

Key words: Pyrite, Natural oxidation, XPS, Floatability, Flotation