Depression mechanism involving Fe3+ during arsenopyrite flotation

•The flotation performance of arsenopyrite following Fe3+ treatment was examined.•The impedance of arsenopyrite was improved by treatment with Fe3+.•The floatability of arsenopyrite decreases with increasing pH.•Fe3+ adversely affects the flotation of arsenopyrite, especially at high pH.•Treatment with Fe3+ improves the zeta potential of the arsenopyrite surface.