Influence of gas flow rate and frothers on water recovery in a froth column

Froth plays an important role in the froth flotation separation of minerals. In froth and foam liquid drains away due to gravity until equilibrium is reached and at the same time is carried upwards by the moving gas phase. This paper aims at better understanding of the influence of the superficial gas velocity and frothers on the liquid drainage in foam and liquid recovery rate from the froth column. The obtained experimental data shows that the available standard drainage theory does not properly describe the influence of gas flow rate and Dowfroth 250 frother on the liquid recovery rate. The theory overpredicts the liquid recovery rate from the froth column. The improvement of the standard theory by inclusion of the contribution of the vertex geometry to the liquid drainage in foam does not resolve this problem. It appears that the liquid drainage process in the froth column is controlled by the interfacial properties of the adsorbed surfactants at the gas–liquid interface.