The recovery of coarse particles by flotation is a long-standing challenge for the mineral processing industry. Recent developments in flotation cell design have produced a flotation machine specifically designed to enhance the recovery of ultra-coarse composite mineral particles. The flotation machine is part liquid fluidised bed and part traditional flotation machine and uses a three-phase fluidised bed as the contact zone for particles and bubble within a mineral slurry.

A three phase CFD model of a laboratory scale cell was developed to model the liquid-solid-gas flow and gain an insight into the hydrodynamic phenomena in the cell. Two modelling approaches were used to predict the liquid-bubble-particle flow. The model predicted three distinct regions with a packed bed in the base of the cell, a region above the liquid-gas sparger where the particles are well fluidised with bubbles interacting with the particles above which is a fairly quiescent liquid with slow rising bubble plumes. Results show that key flow patterns can be captured by the model, but that bed expansion was over predicted when compared to measurements.