Abstract: A method of and apparatus for removing a slurry having shear-thinning visco-plastic rheological properties from a reservoir containing a body of the slurry of such high viscosity that removal is impractical by conventional means, such as gravity flow or suction. The method comprises creating a flow of shear-thinned slurry in a submerged region of the body of slurry to entrain adjacent slurry of high viscosity, and then transferring some of the reduced viscosity slurry from the reservoir.

Abstract: A method of and apparatus for removing a slurry having shear-thinning visco-plastic rheological properties from a reservoir containing a body of the slurry of such high viscosity that removal is impractical by conventional means, such as gravity flow or suction. The method comprises creating a flow of shear-thinned slurry in a submerged region of the body of slurry to entrain adjacent slurry of high viscosity, and then transferring some of the reduced viscosity slurry from the reservoir.

Abstract: A method of and apparatus for the thickening of mud-like slurries produced during the course of industrial processes, e.g. the thickening of red muds produced during operation of the Bayer process for the production of alumina. The invention involves the step of feeding the slurry, a fluocculating agent and washing liquor to a deep thickening vessel having an underflow outlet for the thickened slurry and an overflow outlet for clarified washing liquor. The solids content of the slurry leaving the underflow outlet is increased and kept constant by the use of a stirrer having a number of generally vertical rod-like members rotated in the vessel above the underflow outlet. The stirrer enhances dewatering of the slurry and prevents undue build up of thick inactive mud which may block the outlet or cause fluctuations in the solids content of the thickened slurry.