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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.

Column flotation is widely used for the beneficiation of fines in the mineral processing industry. The kinetics in the column flotation is mainly influenced by the hydrodynamics and the flotation sub-processes such as bubble particle collision, attachment, and detachment. Computational fluid dynamics (CFD) is a popular tool that can be used to evaluate flotation kinetics. However, most of the published works on the flotation kinetics with CFD were limited to mechanical flotation cells. In the current investigation, a CFD model is applied to explore both the hydrodynamics and kinetics of the column flotation. CFD simulations are performed for two-phase systems of column flotation on the Eulerian-Eulerian framework. The standard k-ε turbulence model is utilized in this methodology along with the drag, lift, and virtual mass forces. The hydrodynamic parameters such as axial, and radial gas holdup and its distribution were predicted from the CFD simulations and validated with Electrical Resistance Tomography (ERT) experimental results. In the kinetic study, the flotation kinetic sub-processes, such as bubble-particle collision, adhesion, and detachment were also predicted. The error between the ERT experimental and CFD simulations was found to be 2.71 and 6.75%, respectively at 0.006 and 0.018 m/s superficial air velocities. The effect of particle contact angle and particle size on the kinetic constants of attachment (