An evaluation of froth recovery measurement techniques

The potential mineral recovery from an industrial flotation cell is believed to be significantly affected by particle dropback in the froth phase-especially in scavenging operations. Froth recovery, a parameter used as a measure of this effect, is often reported to be less than ten per cent in these applications. There is therefore tremendous potential to improve flotation machine performance through a better understanding of the froth phase. To enable these types of evaluations, it is important that one can reliably and accurately measure froth recovery. There are a number of different techniques for measuring froth recovery outlined in the literature. This paper will review these different techniques, outlining their strengths and limitations. Metso has built a fully instrumented 3 m3 transportable flotation rig which can be operated in different modes of operation. Various froth recovery measurement techniques were tested using this rig whilst it was operated at Rio Tinto's Northparkes copper operation. This paper presents the results of this experimental program - comparing the different froth recovery measurements and using statistical techniques to evaluate measurement error