Online Optimization of a Gold Extraction Process

A phenomenological dynamic model of gold ore leaching process in agitated tanks is derived and calibrated with a set of industrial data. This model is used to simulate the dynamic behavior of a three-tank industrial plant and to test the performance of the uncontrolled plant, a feedback control system and an online optimization strategy. The results for the open loop circuit (uncontrolled plant) show large losses of gold at low reagent (cyanide) consumption. The regulatory control of the cyanide concentrations in the first tank helps in improving the economic efficiency. The optimal strategy is able to keep the three cyanide control loops at their optimal set points in order to cope with the disturbances and minimize an economic objective function containing both the leaching cost and the gold losses.