Abstract: A cast iron hydrocyclone (1,21) made of separate parts joined together, wherein at least two of the parts (2,3; 22,23) are held together by a pair of separate collars (7,8; 26,28) connected to one another, each collar being anchored to one or the other of the parts. The parts may be so anchored by bearing against an anchor provided on the parts.

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.

Abstract: A spiral concentrator (1) comprising a spiral trough (2) mounted on a central column (3) which is characterized therein that, in comparison with a conventional trough having a profile (11) which is generally concave and which slants downwardly from an outer edge of the trough towards a central column, the profile (8) of the trough is deepened in a section of the trough adjacent the central column of the concentrator.