CFD Modeling of Three-phase Flotation Column Incorporating a Population Balance Model

Abstract

A Computational Fluid Dynamics (CFD) model was developed and validated against published experimental data to understand the effect of slurry concentration on bubbles’ coalescence process in flotation cell. The existing flow field was modelled for two- phase (gas-liquid) and three-phase (gas-liquid-solids). The simulations were carried out using the commercial flow simulation software AVL-FIRE 2009.2 for Jg= 0.94-5.01 cm s-1 Cs= 0-200 kg m-3, respectively. Modelling calculations have been conducted using Eulerian–Eulerian multiphase model with k-ɛ turbulence model for the liquid phase. In the present study, the population balance equation for bubble break-up and bubble coalescence rate and the interfacial exchange of mass and momentum as well as bubble-particles attachment and detachment have been included in the CFD code by writing subroutines in FORTRAN. Comparisons of the predicted results against measured gas holdups and axial pressure profile show reasonable agreement without using any fitting parameter. With the increase of slurry concentration, the gas holdup in a flotation column decreased. These results are in line with those of previous studies. The results also show that the addition of solid particles reduced the size of bubbles in a flotation column.