Selective flotation separation of molybdenite from chalcopyrite using glutathione as a green and efficient depressant: Applications and mechanisms

Efficient and sustainable flotation separation of chalcopyrite and molybdenite is challenging due to the similar inherent floatabilities of the two minerals. Glutathione (GSH) was investigated as a green depressant for improving copper–molybdenum (Cu–Mo) flotation separation, based on the hypothesis that its functional groups selectively bind chalcopyrite surface metal sites. Micro-flotation tests showed that at pH 7 and a GSH dosage of 40 mg/L, Mo recovery in the froth exceeded 98 %, whereas chalcopyrite recovery decreased to 9.36 %. Zeta potential and contact angle analyses confirmed that GSH strongly adsorbed onto the chalcopyrite surface, reducing its surface hydrophobicity, while adsorption on the molybdenite surface was negligible. Fourier transform infrared and X-ray photoelectron spectroscopy analyses revealed that the –SH, –C O, and –NH 2 groups in GSH chemically reacted with Cu or Fe atoms on the chalcopyrite surface, forming strong surface coordination bonds. Density functional theory calculations indicated that the -SH group of GSH formed covalent bonds with both Cu and Fe atoms on the chalcopyrite surface. These results highlight the strong potential of GSH as an environmentally friendly alternative to conventional chalcopyrite depressants.