Abstract: Improvements are disclosed in apparatus for air classifying mineral particles by size. The apparatus is of the type including a vertically oriented flow channel for carrying an upwardly directed air flow stream in which the particles are dispersed and a cylindrical air classifier mounted in the flow channel. The classifier has a cage which is rotatable about a vertical axis and is laterally open to the flow channel. A plurality of spaced vertical rejector blades are mounted about the lateral periphery, and the cage is closed at its lower end by a support plate. An outlet is connected to the classifier interior for withdrawing particles passing radially through the blades for collection; and air drawing device is connected to the outlet for drawing the air stream and particles into the classifier and establishing an upward flow of air and dispersed particles within channel.

Abstract: An improvement is disclosed applicable to systems where a mineral ore, such as a crude kaolin is introduced into a high shear, high energy mixing device with a suspending fluid and dispersing agents added to the same mixing device at controlled rates to produce a suspension with a solid content not more than 72% by weight. The process is applicable to systems where inorganic materials are suspended in a slurry, using water as the suspending fluid, in the presence of a dispersing agent, as for example in the processing of kaolin clay where the crude clay is formed into an aqueous suspension for the purpose of removing impurities and further processing. Heat is applied to the fluids in or before entering the mixing zone of the mixer, in sufficient quantity to raise the temperature of the suspension by at least 10.degree. C. This lowers the flow resistance of fluids in the mixing zone.