Modelling of negative bias column for coarse particles flotation

A model for coarse particle flotation in columns operating with negative bias is presented. The model assumes plug flow of particles and bubbles, low turbulence, and a collection mechanism based on bubble-particle interception. Experimental results obtained with quartz and calcite are in close agreement with the predicted values for particle sizes in the range 100 to 700 microns. For a given column length recovery depends mainly on bubble size, air hold up and particle size.