The interaction mechanism of Fe3+ and NH4+on chalcopyrite surface and its response to flotation separation of chalcopyrite from arsenopyrite

The application of Fe3+ and NH4+ in the flotation separation of chalcopyrite and arsenopyrite were investigated by micro-flotation tests, infrared spectroscopy, local electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy, Time-of-flight secondary ion mass spectrometry, surface adsorption experiments and inductively coupled plasma mass spectrometry. Finally, it mainly explained the interaction mechanism of Fe3+ and NH4+ on chalcopyrite surface. The micro-flotation tests showed that the combined use of Fe3+ and NH4+ can not only inhibit arsenopyrite but also activate chalcopyrite. The action of Fe3+ on the surface of the two minerals leads to a deeper oxidation of the mineral surface, and hydrophilic compounds are produced on the mineral surface to inhibit flotation. The X-ray photoelectron spectroscopy and surface adsorption experiments showed that after addition of NH4+, the hydrophilic compounds on chalcopyrite surface treated with Fe3+ did not decrease, but the adsorption of xanthate significantly increased. The inductively coupled plasma mass spectrometry showed that ammonium chloride can react with the copper sites on the surface of chalcopyrite, causing a small amount of copper to dissolve. It is speculated that the mechanism is that it reacts with Cu sites on the surface of chalcopyrite under the action of dissolved oxygen after the addition of ammonium chloride. The dissolved Cu2+ on the mineral surface forms a relatively stable ammoniacal copper complex ion (Cu (NH3) n+) with ammonium. These ammoniacal copper complex ions undergo redox reactions with xanthate, which capture the electrons in the copper ammonium complex and Cu (I) to produce cuprous xanthate and dixanthogen. Cuprous xanthate precipitates and adsorbs on the surface of the mineral, while the dixanthogen physically adsorbs around the cuprous xanthate.