THE CORRELATION BETWEEN THE FROTH RHEOLOGICAL PROPERTIES AND ITS WATER CONTENT E. Burdukova, Dr D.J. Bradshaw and Prof. J.S. Laskowski Mineral Processing Research Unit, University of Cape Town, Cape Town, South Africa [email protected] ABSTRACT

Water content of froths is a vital component of overall structure of the froth phase in flotation systems. It has been widely recognised that the froth phase of flotation systems plays a vital role in their performance. Relatively little is known about the mechanisms that govern froth phase behaviour and therefore no comprehensive understanding exists to explain the behaviour of three-phase flotation froth. The modelling of water recovery of froths is one of the areas in need of more detailed investigation. Froth water content strongly affects the amount of entrained material that is contained in the froth and therefore plays a vital role in determining the resulting concentrate grade. Froth water content is also a widely accepted indicator of froth stability. Froth stability governs the bursting and coalescence of bubbles and consequently has a great effect on the detachment of hydrophobic particles and therefore governs the recovery of flotable material. A method has been developed, whereby the rheological properties of foam are used to predict its water content. Rheology has been widely used in the past in order to analyse highly stable, two-phase foams in the dry limit, such as polyurethane and shaving foams. By contrast, the foam used in this study was generated under the conditions similar to those used in froth flotation and consequently contained large amounts of water and was highly unstable. In order to vary the foam water content, parameters such as aeration rate and surfactant dosage were varied. The results of the study show that a significant relationship exists between the rheological properties of the foam and its water content. This demonstrates that this technique can be successfully used to model the water content of two-phase foams. In this study, two-phase foam was used as a precursor to investigating rheological properties of the-phase flotation froths.