337 / 2024-03-15 20:55:21

Interaction mechanism of solid surfaces and bubbles with different surface mobility for improving flotation of fine particles

flotation,thin liquid film,bubble surface mobility,fine particles

6、能源资源清洁加工与转化利用 > 1、矿物加工基础理论

A mobile air-water interface can significantly enhance the attachment of bubbles on hydrophobic solid surfaces by weakening hydrodynamic resistance during film thinning. This property has essential implications for many industrial applications including flotation and oil sands extraction. Surface mobility of bubbles was characterized in different aqueous systems based on bubble rising technique. Film drainage was quantified by employing high-speed microscopic interferometry, and interaction forces were analyzed. Furthermore, the significant effect of bubble surface mobility on bubble-solid surface interactions was examined by flotation performance. In the presence of surfactants, bubbles with immobile interfaces were validated by the declined rising velocity and near-spherical shape. Under immobile conditions, the earlier build-up hydrodynamic force had a stronger influence on film thinning than surface forces, as evidenced by the greatly prolonged drainage time. To reach the identical film thickness (~100 nm), bubbles in 117 μM MIBC solutions required approximately 16 s, compared with 2 s in 600 mM KCl solutions. The ultimate flotation recovery was thus decreased by 10% in surfactant solutions. This study not only enhances the understanding of how bubble surface property works in film thinning, but also opens up an avenue for enhancing flotation by regulating bubble surface mobility.