Apparatus for extracting alumina from bauxite
AssigneeEkato-Werk Erich Karl Todtenhaupt
InventorsArther J. Tielens, Wolfgang Muller, Erich K. Todtenhaupt
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Abstract
A supersaturated solution of ground bauxite and caustic soda is fed to a plurality of stirrer tanks in a product cascade. Each of these stirrer tanks of the product cascade has three vertically spaced zones with differing solid contents, a central vertical shaft and at least three vertically spaced paddles carried on the shaft and each extending into a respective one of the zones. The paddles are so constructed as to differently act on the solid in dependence upon the solid contents in each zone.
Claims16
A separator-agitator tank for separating alumina from bauxite, comprising a closed vessel having a wall bounding an inner chamber which forms different upper, middle and lower treatment zones arranged to accommodate a solution with relatively low, medium and large solid contents, respectively;
- a rotatable shaft in said chamber which is radially inwardly spaced from said wall, and centered on and rotatable about an upright axis;
- a plurality of radially extending arms on said shaft for joint rotation with the latter and including at least one upper, middle and lower arm vertically spaced from each other and each located in a respective one of said different treatment zones;
- and a plurality of paddles arranged so that each of said arms is provided with at least one of said paddles for joint rotation therewith and the paddles of different arms are located in said different treatment zones, each of said paddles located in one of said zones being constructed differently than any of said paddles located in the other of said zones so that said paddles differently act on the solution, in dependence upon the solids content in each of said different treatment zones during rotation of said shaft, with relatively low, medium and high intensity in said upper, middle and lower treatment zones, respectively, said plurality of paddles including at least one lower paddle on said lower arm and extending in radial direction substantially from said shaft up to said wall of said vessel by a predetermined distance, said plurality of paddles further including at least one middle paddle on said middle arm, said middle paddle having inner and outer segments spaced from one another in said radial direction, said segments being inclined at different angles to an axial plane, said plurality of paddles further including at least one upper paddle on said upper arm and located adjacent to said wall and extending in said radial direction by a distance which is smaller than the distance by which said lower paddle extends.
Dependencies are inferred from the claim text.