发明申请
US20070178041A1 The bayer process for production of alumina trihydrate by alkaline digestion of bauxite, the process comprising a predesilication step
失效
通过铝土矿的碱性消解生产氧化铝三水合物的拜耳法，该方法包括预消溶步骤
- 专利标题： The bayer process for production of alumina trihydrate by alkaline digestion of bauxite, the process comprising a predesilication step
- 专利标题（中）： 通过铝土矿的碱性消解生产氧化铝三水合物的拜耳法，该方法包括预消溶步骤
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申请号： US11569290申请日： 2005-05-11
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公开(公告)号： US20070178041A1公开(公告)日： 2007-08-02
- 发明人: Eric Tizon , Clotilde Fryns
- 申请人： Eric Tizon , Clotilde Fryns
- 优先权： FR0405405 20040518
- 国际申请： PCT/FR05/01177 WO 20050511
- 主分类号： C01F7/02
- IPC分类号： C01F7/02
摘要：
Bayer process, comprising grinding (L, B) and then digestion (N2, A) of a bauxite by bringing it into contact with a sodium aluminate liquor (20b, 120b). Digestion consists of forming a slurry (3a, 103) that is then treated to separate insoluble residues (5a, 105a) from the sodium aluminate liquor. The liquor is then crystallized (D) and recycled back to green liquor (20, 120) after having been separated from the alumina trihydrate (11, 111) precipitated during crystallization. The process comprises a predesilication treatment (P) during which the ground bauxite is brought before digestion into contact with an aqueous sodic solution that has a content of carbonates, sulphates and possibly chlorides which, expressed as a percentage related to the caustic concentration, is less than half the corresponding impurities content of the spent liquor (8, 108). Preferably, the pure caustic soda used to compensate for caustic soda losses in the Bayer circuit that was previously injected just after evaporation is now added in the aqueous sodic solution for the predesilication treatment.
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