Effects of gas distribution profile on flotation cell performance: An experimental investigation

A flotation cell that enables the study of the effects of different air distribution profiles on flotation performance has been designed. Three distinct gas fluxes viz. high gas flux at the back of the flotation cell (impeller and gas distribution mechanism at the back), high gas flux at the centre (impeller and gas distribution mechanism at the centre) and high gas flux close to the concentrate weir (impeller and gas distribution mechanism close to concentrate weir). Pseudo-steady state experiments using an artificial ore comprising of 80% silica as gangue and 20% limestone as floatable component were done. Results indicated that high gas rate at the back of the flotation cell resulted in higher limestone recovery when compared to the other gas distribution profiles investigated while high gas flux close to the concentrate weir resulted in high limestone grade. The differences in recovery ranged between 5 and 10% while the grade differences ranged between 0.5 and 5% with high gas flux at the centre produced lower values for all froth depths and gas rates. The effect of gas distribution profile on limestone grade was found to dwindle as froth height was increased; changes in limestone grade ranged between 0.47 and 2% for a froth depth of 10.1 cm while those for a froth height of 6.3 cm ranged between 1.40 and 5%.