COLUMN FLOTATION - A SELECTED REVIEW .1.

This review of recent work on column flotation focuses on three aspects: mixing in the collection zone, maximum gas rates and carrying capacity. The plug flow dispersion model is shown to be adequate for fitting the residence time distribution without resort to compartment models. Care is needed, however, because different boundary conditions and fitting routines lead to different parameter estimates. Maximum gas rates can be defined by three distinct phenomena: loss of bubbly flow, loss of interface and loss of positive bias. All carry the potential for loss of performance, although in some cases performance can be maintained into negative bias. An update to the carrying capacity equation is presented and the use of lip length rather than area as the criterion is considered.