RATE OF COLLECTION OF PARTICLES BY FLOTATION

The capture of a single spherical particle by a bubble in froth flotation is analyzed to estimate both the induction time and the rate of flotation. Both London-van der Waals forces and electrostatic double-layer forces are recognized. The induction time is the time required for the thinning and rupture of the liquid film between the spherical particle and the bubble. With the assumption that the effects of the electrostatic double layer can be neglected, the predicted result for the induction time describes the trends seen in prior experimental studies. When the effects of the electrostatic double layer cannot be neglected, better selectivity between particles having different surface potentials is predicted at intermediate values of the electrolyte concentration. When the effects of the electrostatic double layer can be neglected, an expression for the rate of flotation can be derived up to a proportionality factor. This allows us to draw several qualitative conclusion regarding the rate constant that are supported by experimental observations. © 1990, American Chemical Society. All rights reserved.