Predicting flotation behaviour – the interaction between froth stability and performance

Abstract

Froth behaviour has a major impact on the overall performance of flotation cells, with the froth controlling the water recovery and entrainment, as well as having a significant impact on the recovery. Froth stability, including bubble coalescence and the bursting of the bubbles at the froth surface, are the key drivers of froth performance. Even though the froth stability is hard to directly control, it is important to understand how this stability impacts froth performance parameters such as the water recovery. In this paper it is shown how a theoretical understanding of froth behaviour based on foam physics can be used to link stability to performance. The extent to which these simplified theoretical relationships can describe the complex behaviour seen in real flotation systems at both the laboratory and industrial scale are explored. The paper shows how bursting flux depends upon gas flux and how this influences the relationship between the gas flux and the water recovery.