Air-rate profile optimisation: From simulation to bank improvement

Experimental data was used to create a base-case model of a bank of flotation cells at a South African platinum mine on a physics-based froth zone simulator, FrothSim. FrothSim models the three phases (solid, liquid and gas) in flotation froths and models entrainment and drainage of water and unattached solids, allowing the upgrading effect of a froth to be simulated. Using distributed first order rate constants, the correct overflow rates for each of the selectively floated minerals down the bank were accurately simulated. The entrained minerals and water rates were correctly predicted by the froth physics.The rate constants and froth parameters were used unchanged in predictions at different air-rate profiles down the bank. This was carried out with the two aims of increasing the grade at the head of the bank, where the concentrate goes direct to the final concentrate of the plant, and increasing the cumulative recovery at the end of the bank.Once an optimum air-profile had been determined using the simulations, this profile was tested in a froth experimental sampling campaign and confirmed the predicted improvement in flotation performance along the bank.