Role of hydrodynamic cavitation in fine particle flotation

Abstract High energy dissipation, high feed velocity and relatively high feed pressures have been used in some recently developed flotation cells to enhance fine particle flotation. One contributing factor to the high flotation kinetics demonstrated in these new cells may be in-situ bubble formation by hydrodynamic cavitation on hydrophobic particles. This could induce particle aggregation through gas nucleus bridging with the consequently larger particles having a higher collection rate. Both experimental measurements and numerical analysis indicated bubble formation whenever the water vapor pressure was reached. The presence of surfactants and dissolved gas was found to preserve the bubbles generated by cavitation, thus producing more small bubbles. Flotation of fine silica and zinc sulphide precipitates in a flotation device incorporating hydrodynamic cavitation showed a significantly increased flotation kinetics.