| 摘要 |
A process for precipitating alumina trihydrate from a pregnant caustic liquor comprising supplying the pregnant caustic liquor (10) to a precipitation stage of a Bayer plant. The precipitation stage includes an agglomeration stage (A1, A2) and a growth stage (G1, G2... Glast). Precipitation of alumina trihydrate takes place in the precipitation stage to form a slurry of precipitated alumina trihydrate in caustic liquor. During the precipitation process, the slurry is diluted by addition of an aqueous stream (115). This dilutes the caustic concentration of the liquor in the slurry, which increases the driving force for precipitation, thereby increasing yields from the precipitation process. The dilution stream may be added to the slurry as a single stream or a plurality of streams.
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