Unveiling the depression role of quercetin in selective flotation separation of chalcopyrite from pyrite at low alkalinity

In flotation, the separation and concentration of copper-iron sulfide ores are usually carried out at high alkalinity to depress pyrite, and plenty of lime could block the flotation pipeline and affect the recovery of precious metals during practical operation. Herein, the current research hotspot to achieve the separation of copper-iron sulfide ores under low alkalinity. This paper presented an eco-friendly reagent, quercetin, for the flotation separation of chalcopyrite and pyrite, and investigated the effect on the flotation performance of the two minerals. The interaction mechanism of quercetin with mineral was demonstrated using zeta potential measurements, atomic force microscopy (AFM), surface adsorption measurements, Fourier-transform infrared spectroscopy (FT-IR), and X-ray Photoelectron Spectroscopy (XPS). The flotation results showed that the depressive effect of quercetin on pyrite was more pronounced in comparison to its impact on chalcopyrite at pH 8.0, and the chalcopyrite recovery reached 90 %, whereas that of pyrite was under 10 %. The surface analysis revealed quercetin chemisorption on the mineral surface through interaction with metal sites. In the presence of quercetin, the quercetin significantly diminished the ability of pyrite to adsorb xanthan but had minor effects on the adsorption of chalcopyrite.