Flotation Kinetics

The physical variables that influence the rate of flotation are examined. The probabilistic model of flotation is used to establish the effect of the particle si2e and density, bubble size and agitation on the rate of flotation In quiescent flotation, it appears that the flotation rate is limited by the particle-bubble collision and subsequent attachment of the particle to the bubble. For fine (<20 μm) or low density particles the remedy for low recovery rates would be to either use small bubbles of the order of 100 μm, or to use moderate to high agitation with larger bubbles In the usual turbulent conditions, the limit is set by the destruction of the bubble-particle aggregates. Broadly speaking, the same parameters favour both attachment and detachment so that the ultimate flotation rate is a compromise between these two competing mechanisms The bounds which define the best agitation level and bubble size to use are strong functions of the particle size and density. This results in conflicting requirements for the optimum flotation of the fine and the coarse particles. Best conditions for the flotation of each are indicated.