This process of mechanical dispersion of air bubbles 0.2 to 2 mm in diameter is mainly used for the separation and differential concentration of ore pulp. It ‘s possible to add a collector agent and an activator or a depressor in the water.

In treating oily water from oil refineries, the separation of oil by mechanical flotation is called froth flotation. It is achieved by adding an organic coagulant or demulsifying agent. Flotation units are constructed with three or four cells in series.

Froth flotation by injection of air may also be used for the separation of surfactants.

Resource: Water treatment Handbook Degrémont