Flotation separation of pyrite from arsenopyrite by surface discharge plasma modification

[Display omitted] •SDBD plasma modification enhanced the flotation separation of pyrite from arsenopyrite in pulp.•The dissolution of reactive species and free radical chain reactions created conditions for plasma modification.•The oxidation degree of the mineral surface was proportional to the residence time in the oxidation zone.•SDBD plasma modification promoted the enrichment of high-valence oxidation products.•Plasma modification preferentially occurred in the defect area on the particle surface. Low-temperature plasma has not been reported to be applied to pulp system although it has been proved to be an effective method for the selective modification of minerals. In this research, surface dielectric barrier discharge (SDBD) low-temperature plasma was introduced into the pulp through a bubble generator, and its modification mechanism on arsenopyrite and pyrite was investigated. SDBD plasma exhibited an excellent selectivity where the concentration of hydrophilic oxidation products on the surface of plasma-modified pyrite was much less than arsenopyrite. The introduction of plasma into the pulp resulted in a longer residence time of the pulp chemistry of arsenopyrite in the stable oxidation region than that of pyrite. Plasma modification significantly enhanced the oxidation degree of the defect area on the surface of arsenopyrite, which resulted in the decrease of its hydrophobicity and thereby hindered the adsorption of collector and the oxidation of xanthate ions into dixanthogen. Since its environmently-friendly property, SDBD plasma modification has a broad application prospect in the flotation separation of polymetallic sulfide ores.