Application of exopolysaccharides synthesized by Xanthomonas campestris in an efficient separation system of refractory chalcopyrite and molybdenite

Abstract

Bacterial polysaccharides get an abundance of attention owing to their distinctive biological activity and promising applications. Recent research found that the specificity of the molecular structure of exopolysaccharides (EPS) can be used to accomplish selective regulation of the physicochemical properties of mineral surfaces. The development and application of novel microbial EPS as a flotation reagent for chalcopyrite and molybdenite separation possesses a promising development prospect. Consequently, we attempted to create effective and sustainable molybdenite depressants in this work by optimizing the strain's fermentation settings and identifying the molecular structure of the generated EPS. Fermentation condition tests revealed patterns of influence of fermentation parameters on EPS yield, the viscosity average molecular weight, and biomass during the fermentation process, and optimized the optimal fermentation conditions. Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and ion chromatography (IC) analyses clarified the structure of the EPS in terms of monosaccharide composition, glycosidic bonding, and functional groups. Mixed mineral flotation tests proved that a low dosage of polysaccharide reagent (100 mg/L) at pH 10 effectively inhibited molybdenite and achieved separation targets of 21.96% Cu and 2.63% Mo in the concentrate, with separation efficiencies (SE) of 72.67% and 55.78% for Cu and Mo, respectively.