Fundamental Study Of Cavitation In Flotation

The generation of microscopic bubbles by cavitation may enhance particle-bubble attachment and improve flotation performance. It is shown in this paper that tiny bubbles or cavities can be generated by strong shear and turbulence in high speed liquid flows. These conditions create the necessary pressure fluctuations in the bulk water to cause the local pressure to drop below a critical value. The formation of bubbles is favored by high dissolved gas contents to promote gas diffusion into the cavities, and by the presence of surfactants to provide some mechanical strength due to the adsorbed film. Experimental results on bubble formation by cavitation and consequent flotation of fine silica (d50 = 1.6 µm) are presented.