Modelling and simulation of rougher flotation circuits

Abstract At present, large mechanical flotation cells of 100 to 300 m 3 are used in rougher operation in different industrial flotation plants around the world. However, in spite of the advances in fundamental research and the notable growth in equipment size, there is still a lack of reliable data for industrial flotation modelling and simulation. In this work, a procedure for modelling and simulating rougher flotation banks that is based on operating variables and parameters fitted by empirical data from plant measurements is presented. Recently, a new methodology for describing industrial flotation by separating the collection and froth zones has been developed. This approach consists of using a new apparatus for direct bubble load measurement below the pulp–froth interface in industrial cells. The procedure allows independently estimating the froth recovery and the collection zone recovery. Metallurgical characterisation is developed by plant sampling, mass balance adjustment and applying a short-cut method for kinetic characterisation of flotation banks. In addition, the effect of grinding is characterised using flotation models with distributed flotation rates (for each particle size class) and a low number of parameters. From the experimental data, a non-linear distributed model to simulate rougher flotation banks was developed, which allows describing the industrial operation as a function of the main operating variables (e.g., mass flow rate, solid percentage, grinding degree, pulp level and superficial air rate). The simulator was calibrated and validated using experimental data from the rougher operation at El Teniente Division, Codelco-Chile. The new approach is a practical tool that is useful for flotation operation diagnosis, for robust design and analysis of new control and optimisation strategies and for evaluation of the effect that design and operating variables have upon the collection and froth zone performance in large flotation cells. This methodology can be applied to other flotation operations, such as cleaner and scavenger circuits that use mechanical flotation cells.