Grade-recovery curves: A new approach for analysis of and predicting from plant data

Flotation performance is most commonly represented using grade-recovery curves, with a shift upwards and to the right indicating an improvement in performance. The problem with using grade recovery curves, especially on plant data, is that position and shape of the curve is strongly influenced by both the feed rate and grade to the circuit. In this paper a method for representing flotation performance in a way that is independent of the feed grade and rate is presented. This uses the principle that both the concentrate grade and mass pull are defined by what is in the cell and the cell operating conditions. This means that for cells operating at the same conditions, there is a single relationship between the tailings grade and concentrate grade and between the tailings grade and mass pull. In this paper a semi-empirical form for these relationships is presented. Using these relationships together with a mass balance the effect that feed rate and grade have on flotation performance is explored.