Method of and apparatus for thickening red muds derived from bauxite and similar slurries

摘要

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.