ABSTRACT
This chapter covers the mechanisms involved in pulp—froth transfer as well as those that is affected by the changing nature of the froth with increasing height above the pulp—froth interface. It provides an overview of the major problems confronting the researcher in characterizing froth behaviour, especially if mathematical models are used to quantify individual mechanisms or the overall process. In flotation columns, wash water is sprinkled in the froth to prevent entrained material from entering the concentrate. Entrainment refers to the non-selective transfer of particles into the froth in the wake of the mineralized bubbles, and contained in the film of slurry around the bubble as it rises higher up into the froth. Froth recovery is determined by the size of the bubbles, the extent to which they are loaded with hydrophobic particles, and the rate at which the bubbles are removed into the concentrate.
