Adsorption performance and mechanism of eco-friendly and efficient depressant galactomannan in flotation separation of chalcopyrite and molybdenite

Abstract

The effective separation of chalcopyrite and molybdenite is the most serious challenge for the utilization of copper and molybdenum resources. One of the effective methods to solve this problem is to explore and develop a series of highly efficient depressants. In this work, a novel non-toxic and highly efficient depressant, galactomannan (GM), was applied to separate chalcopyrite from molybdenite using sodium butyl xanthate (SBX) as a collector. The selective depression behavior was evaluated via flotation experiments; the results showed that GM effectively depressed the flotation of molybdenite, whereas it exhibited weak depression effects on the flotation of chalcopyrite. The effective separation of the two minerals could be achieved using a reagent scheme consisting of 20 mg/L GM and 30 mg/L SBX at pH 5.52. The selective depression mechanism of GM for molybdenite was investigated by zeta potential measurements, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and interaction energy calculations. The results demonstrated that the hydrophobic interaction between molybdenite and GM was the main differential driving force relative to the interaction between chalcopyrite and GM, and led to different adsorption capacities of GM on the two minerals. Moreover, after the addition of GM, the interaction between molybdenite and SBX involved physical adsorption, while chalcopyrite and SBX interacted via chemical adsorption. Overall, these results suggest that GM can be employed as a potential depressant for the selective separation of chalcopyrite from molybdenite by froth flotation.