Alcan International Limited

Rio Tinto Alcan International Limited

Renald Dufour

Guy Peloquin

Andrew N Carruthers

Alain Boivin

Guy Simard

Donald L Puxley

Rock Lemyre

Donald Puxley

Method and apparatus for separating components of slurries by gravity settling thereby forming a thickened slurry and a clarified liquid. The apparatus comprises a vessel for decanting a volume of slurry, the vessel having a top and an interior formed by a side wall and a bottom wall for holding the slurry, a slurry inlet means, an outlet for the clarified liquid near the top of the vessel, and a slurry withdrawal apparatus for removal of the thickened slurry from the vessel at or near the bottom wall thereof. The slurry withdrawal apparatus physically engages a portion of the slurry within the vessel interior and transports it through a vessel outlet. The apparatus may include an elongated, rotatable, open spiral-shaped element extending a distance into the vessel from outside near the bottom wall of the vessel, the open spiral-shaped element being in direct and open communication with the interior of the vessel over at least a significant portion of the distance, and a rotational drive mechanism for rotating the open spiral-shaped element, at least intermittently.

Apparatus for production, withdrawal and transfer of highly viscous slurry

The invention relates to a settler for decanting mineral slurries and a method thereof. The settler comprises a tank for holding and decanting a body of slurry to form a thickened slurry as a lower layer and a clarified liquid as an upper layer, the tank having a side wall, a bottom and a top, an outlet for the thickened slurry at the bottom of the tank, an outlet for the clarified liquid layer near the top of the tank, a slurry inlet means near the top of the tank for introducing fresh slurry into the tank, the slurry inlet means having a slurry opening through which fresh slurry joins the body of slurry in the tank, and a stirrer having a generally vertical axis around which the stirrer rotates or reciprocates. The slurry opening is displaced laterally relative to the generally vertical axis of the stirrer and the slurry inlet means is configured to allow the fresh slurry to enter the slurry body without accumulating solids from the fresh slurry at the slurry opening.

Apparatus for and method of settling of mineral slurries

A process is described for removing dissolved silica from an alkaline solution containing sodium aluminate, e.g. a Bayer process solution. The process comprises contacting the alkaline solution with a slowly stirred bed of particles comprising coarse silica sand or a mixture of coarse silica sand and particles of sodalite, whereby the dissolved silica is precipitated out of solution to form a precipitation of desilication product dispersed in the solution and separating the desilication product solids from the alkaline solution to obtain a desilicated alkaline solution.

Process for the removal of silica from an alkaline solution containing

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Jonquière, Canada

Renald Dufour