| 摘要 |
PROBLEM TO BE SOLVED: To reduce a calcium content in aluminium hydroxide by controlling calcium concentration in the manufacturing process of aluminium hydroxide by Bayer's method. SOLUTION: A separation process comprises the steps: an alumina containing ore and an alkali solution is mixed; the mixture is heated to dissolve an alumina portion in the ore into the alkali solution to be an aluminate alkali solution; a coagulant is added to the mixture to precipitate non-dissolved portion; the aluminate alkali solution is filter by adding a filter aid to the aluminate alkali solution before a process of extracting aluminium hydroxide after the separation process are contained; aluminium hydroxide is to extracted from the filtered aluminate alkali solution; calcium aluminate is added to the coagulant in the separation process; and calcium aluminate is added to the filter aid in the filtering process. COPYRIGHT: (C)2003,JPO
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