Enhanced kaolinite flotation using amine coated nanobubbles

Abstract

In this study, kaolinite flotation using normal water and water containing pure nanobubbles (NBs) or amine coated NBs (CNBs) was investigated and the micro-flotation results showed that kaolinite floated the best when water containing CNBs was used. Rheology, settling and zeta potential tests, together with particle size distribution analyze were further employed to examine the effect of NBs (coated or not) on kaolinite particle association and its correlation with the flotation of kaolinite particles. While the zeta potential and particle size distribution results indicated an intensified attachment of CNBs on the surfaces of kaolinite, the rheology and settling results revealed the predominance of edge-to-edge and edge-to-face associations of kaolinite platelets in the presence of CNBs. It is proposed that owing to the formation of three-dimensional clay clusters which appears to be induced by the CNBs, the more favorable silica planes of kaolinite are exposed and the subsequent adsorption of amine on such planes of the kaolinite aggregates (flocs) significantly improves the flotation of kaolinite.