Froth flotation can be intensified by applying ultrasound at different stages of the process, leading to improved separation behaviour. The ultrasound-induced effects are primarily caused by the phenomenon of cavitation. The alternate sonic pressures generates vapour bubbles that grow and implode with high velocities, thereby applying high pressures, high shear stress and high temperatures. Effective cavitation, i.e. a locally and temporally concentration of energy, only appears in case of inharmonically oscillating bubbles, having diameters smaller than the called resonance diameter.
Further parameters, that influence the cavitation are:
Ultrasound supported flotation has been used to improve the fine coal flotation and cleaning of PHC and PAH contaminated soil.
H.Z. Kuyumcu und S. Özkan:Investigations of effects of ultrasonic waves on various phases of froth flotation, Proceedings of XXIII. International Mineral Processing Congress, Vol. 1, ISBN 975-7946-27, Istanbul 2006, S. 598-603
H.Z. Kuyumcu und S. Özkan: The Influence of Ultrasonics on Coal Flotation, Aufbereitungs Technik 47 (2006), Nr. 1-2, S. 23-33
H.Z. Kuyumcu und J. Rosenkranz: Investigation of the Effect of Ultrasound on the Froth Flotation of Fine Soil contaminated with PHC and PAH. Proceedings of XI. International Mineral Processing Symposium, Ankara 2008, S. 881 - 889