The role of polyvinylpyrrolidone in the selective separation of coal from quartz and kaolinite minerals

Abstract

High-effective flotation of valuable coal resource from gangue is more challenging due to the increase of ultra-fine minerals in coal slime. Despite the use of novel flotation equipment and process strengthening regulation, the method of flocculation of coal or gangue particles to enhance selective separation draws increasing attention recently. The great potential in selective flocculation of particles makes the development of novel polymer flocculants a research hotspot in this field. Particularly, as a kind of polymeric reagent, polyvinylpyrrolidone (PVP) has great significance in clay aggregation/dispersion whereas there are few related researches in coal flotation. Thus, the effect of PVP on coal flotation was systematically investigated in this study by flotation tests and the measurements of zeta potential, turbidity, FBRM, and X-ray photoelectron spectroscopy. The results proved that PVP would be preferentially adsorbed on quartz and kaolinite surfaces rather than coal. The adsorption of PVP with low dosage induced the aggregation of quartz and kaolinite, as indicated by turbidity and FBRM results, while it basically made no difference on coal. It was discovered that the selective flocculation of quartz and kaolinite by PVP promoted the selectivity of flotation. This study furnishes a novel and feasible polymer flocculant to improve coal flotation efficiency. • PVP as a flotation regulator could reduce the ash content of clean coal. • PVP could improve flotation selectivity by flocculation of gangue particles. • PVP could adsorb preferentially on quartz and kaolinite than coal.