Measurement of Gas–Solid Dispersion Characteristics in a Slurry Flotation Column Using ERT Technique

Abstract

This work mainly aims on the investigation of phase hold-up characteristics in a column flotation at different feed solid concentrations performing for an extensive range of working conditions. Phase hold-ups are measured using the electrical resistance tomography (ERT) coupled with pressure transducers technique. Experiments are conducted for two different nature mineral particles: hydrophilic (silica) and semi-hydrophobic (oxidized coal). The impact of gas superficial velocity, feed superficial velocity and pulp slurry height for a fixed sparger and frother addition on the gas and solid dispersion are studied. Gas hold-up increases with the gas flowrate and slurry feed rate, decreases with solid concentration. Further, bubble dynamics is estimated using coupled ERT with dynamic gas disengagement (DGD) approach. It is found that the solid's presence affect the bubble swarm velocity thereby causing local gas holdup to drop. Possible mechanisms due to solid particles on gas dispersion are discussed and verified in the light of current experimental results.