Investigation of calcite flotation by green natural hydrophobic talc nanoparticles as collectors, and the adverse influence of nanoparticle aggregates

Abstract

Hydrophobic talc nanoparticles (T-NPs) were used as natural solid collectors to study calcite flotation in a modified Hallimond flotation tube to optimize process conditions. The results demonstrated that the calcite surface hydrophobicity and resulting floatability significantly changed with variations in the concentration of T-NPs. It was found that by increasing T-NPs amount in the range of 0.4–1.2 kg/ton, calcite flotation recovery increased. Experiments results also revealed that by increasing T-NPs concentration over 1.2 kg/ton, flotation recovery drastically decreased, which was an indication of the formation of suspended T-NPs aggregates, because of their great tendency to aggregate due to agitation. Owing to greater hydrophobicity and floatation kinetic rate of suspended aggregates than calcite surface that covered by T-NPs, they attaching to bubbles quickly and easily, thereby they will have an adverse influence on calcite floatability. Therefore, 1.2 kg/ton of T-NPs was the optimum concentration of nano collector for process recovery. The results of this study clearly showed the promising potential of natural nano particles as an environment friendly collector in froth flotation.