Abstract: A method of aerating a liquid comprising the steps of providing a column, introducing liquid under pressure into an upper zone of the column in the form of a jet of liquid directed in a path, permitting gas to be entrained by the jet of liquid, obstructing the path of the jet of liquid to form a zone of turbulence in which bubbles are formed in the liquid to create a foam or froth bed in the column, and removing the foam or froth.

Abstract: A method and apparatus for separating particulate material. The method includes the steps of delivering a substantially constant supply of feed to a first aerator, aerating the substantially constant supply of feed in the first aerator, introducing the substantially constant supply of aerated feed to a flotation vessel below a froth/liquid interface within the vessel, so that floatable particulate material entrained by air bubbles from the first aerator can float upwardly to the froth/liquid interface. Air is introduced into the liquid phase in the flotation vessel via a second aerator located below the level at which the aerated feed is introduced into the flotation vessel, so that floatable particulate material not entrained by air bubbles from the first aerator, may be entrained by air bubbles from the second aerator, as the air bubbles from the second aerator rise upwardly through the liquid phase to the froth/liquid interface.