| 摘要 |
1,240,354. Dehydrating aluminium hydroxide. KLOCKNER - HUMBOLDT - DEUTZ A.G. 5 Sept., 1968 [6 Oct., 1967], No. 42344/68. Heading C1A. In a method of dehydrating aluminium hydroxide, the aluminium hydroxide is held in suspension in a hot gas stream in dehydration apparatus comprising a series of cyclone separators (1, 2, 3, 4) and a part of the hot aluminium hydroxide is withdrawn from the apparatus and mixed with the damp hydroxide before it is supplied to the apparatus. In the described embodiment the raw material containing surface moisture, produced by the Bayer process, is passed via conveyer 17 to pipe 5 where it is entrained in a hot gas stream and carried into cyclone separator 1, where the solid is separated and passes into cyclones 2, 3 and 4 via pipes 6, 7 and 8. At 19 some of the hot product is returned to 16 where it is mixed with the raw material. Dust may be separated from the gas from cyclone separator 1 in electrostatic precipitator 14 and also added to the raw material. y- Al 2 O 3 from 13 may be converted to stableα- Al 2 O 3 in fluidized bed furnace 9.
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