A computational fluid dynamics model for the flotation rate constant, Part I: Model development

A Computational Fluid Dynamics (CFD) model for the prediction of the flotation rate constant in a standard Rushton turbine flotation tank was developed. The premise for the model development was the assumption that separation by flotation is a first order rate kinetic process. An Eulerian-Eulerian framework in conjunction with the dispersed k-ε turbulence model was supplemented with user defined functions to implement the local values of the turbulent flow into a kinetic model. Simulations were performed for quartz at different operational conditions. The numerical predictions were validated against experimental data and analytical computations using the fundamental flotation model of Pyke et al. (2003). The results showed that the CFD-based model not only captured the trend of experiments for a range of particle sizes but also that the CFD yielded improvements in the predictions of flotation rate constant compared with the theoretical calculations. It was found that the CFD model is able to predict the flotation rate constants of the quartz particles floating under different ranges of hydrophobicity, agitation speed and gas flow rates with lower root mean square deviation compared with the theoretical computations.