Froth stability as a performance indicator in sulphide minerals flotation plants

Abstract

The implications of froth stability for recovery in mineral flotation are often underestimated. In the last years, technology and automation have been widely implemented in flotation plants, so that automatic level control and in-line visual analysis of the froth are now a standard feature in modern concentrators. However, most of the decision making process still relies on the operator's experience. The best flotation strategy is generally determined empirically, and froth stability, in particular, is rarely quantified. In this work, froth stability has been assessed, down the bank, in two different concentrators treating copper sulphide minerals. Froth stability was measured, in situ of the flotation cells, by the use of a transportable device (modified froth stability column), and other froth descriptors, like froth velocity and froth depth, were also measured. Differences in froth stability have been correlated to the different plant operating conditions, and implications on the recovery of minerals across the froth phase are discussed. It is shown that different flotation strategies may lead to similar metallurgical performance, and that froth stability can be a useful indicator to optimise operating conditions in the flotation cells.