Experimental and numerical studies of launder configurations in a two-phase flotation system

Abstract

Studying the effect that different tank configurations have on operating variables in a flotation system is of interest in order to better understand the phenomena taking place in the froth phase. In this work a laboratory scale flotation tank was used to carry out experiments for different launder layouts using a two-phase system that resembles a flotation froth. Stagnant foam zones were observed during the experiments and were linked to specific tank configurations. In addition, recently developed three-dimensional, Computational Fluid Dynamics (CFD) models for the gas and liquid in flotation froths have allowed modelling the behaviour of these phases on non-symmetric tanks. These models are relevant to the study of flotation cells in which the configuration of the overflowing lips or the geometry of the tank result in a flow that cannot be represented in two dimensions due to the lack of symmetry. Simulations were performed for the different launder layouts making use of experimental data, reproducing some of the observed phenomena and making it possible to study aspects of the process that are difficult, if not impossible, to be analysed by other means. It is shown that the configuration of the overflows in the cell has an impact on air recovery and liquid overflow rate, and thus important implications for flotation cell design.