Effect of food-grade guar gum on flotation separation of chalcopyrite and monoclinic pyrrhotite in low-alkali systems

The flotation separation of chalcopyrite from monoclinic pyrrhotite using food-grade guar gum (FGG) as a depressant was studied through micro flotation and flotation kinetics experiments, zeta potential, adsorption measurements and scanning electron microscope (SEM) analysis as well as infrared spectroscopy analysis. The flotation tests showed that the reagent scheme of depressant FGG 40 mg/dm3, collector PAX (potassium amyl xanthate) 10 mg/dm3 and frother MIBC (Methyl isobutyl carbinol) 10 mg/dm3 at pH 8.0 could achieve selective flotation separation of chalcopyrite from monoclinic pyrrhotite (a concentrate with Cu grade of 22.35% and recovery of 82.52% was achieved from the mixed minerals flotation), which indicated that FGG exhibited a selective depression effect on monoclinic pyrrhotite The kinetics, zeta potential, adsorption, SEM and infrared studies revealed that the depressant FGG could absorb more strongly on the surface of monoclinic pyrrhotite than chalcopyrite. Additionally, the results revealed that the interaction of FGG with the monoclinic pyrrhotite surface was governed primarily by strong chemisorption, whereas FGG mainly bonded to chalcopyrite through hydrogen bonding bonding. This property was the reason why FGG had excellent depression selectivity toward monoclinic pyrrhotite and weak depression effect on chalcopyrite flotation.