On the role of cavitation in particle collection during flotation - a critical review

Abstract

This paper reviews the fundamentals of recently developed flotation devices, and a new mechanism of particle collection by cavitation/gas nucleation is proposed. It is shown by both theoretical analysis and practical applications that cavitation/gas nucleation accelerates particle-bubble attachment and flotation rates, and offers a means of improving flotation cell designs. A two-stage attachment model is emphasised and used as a possible explanation of the fast flotation rates achieved by some recently developed flotation cells. While the first stage, i.e., the generation of gas nuclei/cavities and their attachment to particle surfaces can be intensified by stirring, high dissolved gas content in the slurry and hydrodynamic cavitation, the second stage, i.e., the capture of the gas nuclei-activated particles by conventional flotation-sized bubbles can be enhanced by high gas holdups and quiescent flow conditions.