VERFAHREN ZUR HERSTELLUNG VON CHROM(III)OXID
    3.
    发明公开
    VERFAHREN ZUR HERSTELLUNG VON CHROM(III)OXID 有权
    用于生产铬(III),氧化

    公开(公告)号:EP2516332A1

    公开(公告)日:2012-10-31

    申请号:EP10790552.3

    申请日:2010-12-08

    IPC分类号: C01G37/00 C01G37/02 C01G37/14

    摘要: Producing chromium(III) oxide, comprises: (a) decomposing an alkali-metal-ammonium chromate double salt at 200-650[deg] C, preferably 250-55O[deg] C; (b) washing the decomposition product obtained in the step (a); and (c) calcining the product obtained in the step (b) at 700-1400[deg] C, preferably 800-1300[deg] C. The alkali metal ammonium chromate double salt comprises sodium-ammonium chromate double salt, which exhibits a molar ratio of ammonia to sodium of greater than 2. An independent claim is also included for producing the alkali-metal-ammonium chromate double salt of formula (M x(NH 4) yCrO 4) (I) or its hydrate, comprising adding ammonia at 55-95[deg] C to an aqueous solution of alkali dichromate of formula (M 2Cr 2O 7) (II). x : 0.1-0.9, preferably 0.4-0.7; and y : 1.1-1.9, preferably 1.3-1.6; or x+y : 2; and M : Na or K.

    VERFAHREN ZUR HERSTELLUNG VON AMMONIUMDICHROMAT
    8.
    发明公开
    VERFAHREN ZUR HERSTELLUNG VON AMMONIUMDICHROMAT 审中-公开
    用于生产重铬酸铵

    公开(公告)号:EP2516331A1

    公开(公告)日:2012-10-31

    申请号:EP10787480.2

    申请日:2010-12-08

    IPC分类号: C01G37/00 C01G37/02 C01G37/14

    CPC分类号: C01G37/14

    摘要: The invention relates to a method for producing ammonium dichromate, comprising the following steps: c) thermal decomposition of an alkali metal-ammonium chromate double salt, especially a sodium-ammonium chromate double salt or the hydrates thereof, at a temperature of up to 200°C, especially between 75 and 190°C, forming ammonium dichromate, and d) separation of the ammonium dichromate from the decomposition product obtained in step c), by crystallisation. Said method is characterised in that the alkali metal-ammonium chromate double salt corresponds to formula Mx (NH
    4 )
    y CrO
    4 or the hydrates thereof, wherein M is Na or K, especially preferably Na, x is a number between 0.1 and 0.9, preferably between 0.4 and 0.7, y is a number between 1.1 and 1.9, preferably between 1.3 and 1.6, and the sum of x and y is 2.