초록 ▼

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 a

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.

대표청구항 ▼

A method of thickening a slurry of red mud derived from bauxite ore or other pseudoplastic mud-like slurry having clay-sized particles, comprising: mixing said slurry with washing liquor and a flocculating agent; passing the mixture into a deep thickener vessel having a substantially cylindrical sid

A method of thickening a slurry of red mud derived from bauxite ore or other pseudoplastic mud-like slurry having clay-sized particles, comprising: mixing said slurry with washing liquor and a flocculating agent; passing the mixture into a deep thickener vessel having a substantially cylindrical side wall, at least one underflow outlet at the bottom for removal of thickened slurry and at least one overflow outlet at or adjacent to the top for removal of clarified liquor; stirring said slurry above said at least one underflow outlet with a stirrer having a rotational profile that decreases in width from top to bottom and which comprises substantially vertical rod-like members to enhance dewatering of the slurry; allowing a body of thick inactive slurry to build up around said cylindrical side wall; and operating said stirrer to maintain a central volume of fluid active slurry in communication with said at least one underflow outlet while causing the stirrer to contact a surface of said body of inactive slurry to cause said body to resist slumping of the inactive mud into said at Apparatus for thickening a slurry of red mud derived from bauxite ore or other pseudoplastic mud-like slurry having clay-sized particles, which comprises: a deep thickener vessel having a substantially cylindrical side wall, at least one underflow outlet at the bottom for removal of thickened slurry and at least one overflow outlet at or near the top for removal of a clarified liquor; means for introducing a mixture of said slurry, washing liquor and a flocculating agent into the vessel at the top; and a stirrer having a rotational profile that decreases in width from top to bottom and which comprises substantially vertical rod-like members located above said at least one underflow outlet for enhancing the dewatering of the slurry; said stirrer being sized and positioned such that, upon rotation, the stirrer allows a body of thick inactive slurry to build up around said cylindrical wall while maintaining a central volume of fluid active slurry in communication with said at least one underflow outlet, and such that a surface of said body of inactive slurry is contacted by said stirrer to cause said body to resist slumping into said at least one underflow outlet.