TOWARDS THE OPTIMIZATION OF FLOTATION COLUMNS USING PREDICTIVE CONTROL

This work details the application of a predictive control strategy to a pilot flotation column working with a two-phase system (water-air). All controlled variables are estimated using electrical-conductivity based techniques. In particular, the results of a new method for estimating the bias rate, based on the measurement of the volumetric fraction of wash water under the interface, is presented. The froth depth is controlled using a PI controller manipulating the set-point of a local tailing flow controller as it is often done in industry. The bias rate and gas hold-up are controlled using a multivariable predictive controller which manipulates the set-point of local flow controllers of wash-water and air. Several operational constraints are considered. Experimental results show that column flotation operation could advantageously optimized using a MPC strategy.