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    PROCESS FOR REDUCING RADIOACTIVE CONTAMINATION IN PHOSPHOGYPSUM
    3.
    发明授权
    PROCESS FOR REDUCING RADIOACTIVE CONTAMINATION IN PHOSPHOGYPSUM 失效
    减少磷光体中放射性污染的方法

    公开(公告)号：EP0096718B1

    公开(公告)日：1989-03-15

    申请号：EP83900379.5

    申请日：1982-12-13

    申请人： UNITED STATES GYPSUM COMPANY

    发明人： PALMER, Jay W. ,  GAYNOR, John C.

    IPC分类号： C01F11/46 ,  C01F13/00 ,  C04B11/06

    CPC分类号： C01B25/228 ,  C01B25/2285 ,  C01F11/468 ,  C01P2004/61

    摘要： Process of two crystallization stages for reducing radioactive contamination of phosphogypsum. In the process anhydrite crystals are obtained through dehydration of the radiation containing phosphogypsum in strong sulfuric acid; a portion of the anhydrite crystals containing the radioactive contamination is converted to substantially radiation free gypsum by crystallizing out on a large solids concentration of radiation free gypsum seed crystals; and coarse radiation free gypsum crystals are separated from small anhydrite crystal relics containing substantially all of the radioactive contamination.

    PROCEDE DE PRODUCTION D'ACIDE PHOSPHORIQUE DU TYPE DIHYDRATE/HEMIHYDRATE
    5.
    发明公开
    PROCEDE DE PRODUCTION D'ACIDE PHOSPHORIQUE DU TYPE DIHYDRATE/HEMIHYDRATE 有权
    DIHYDRATE型半水用于生产PHOSPHORIC

    公开(公告)号：EP2714589A1

    公开(公告)日：2014-04-09

    申请号：EP11723949.1

    申请日：2011-06-01

    申请人： Prayon Technologies

    发明人： HOXHA, Antoine ,  FATI, Dorina

    IPC分类号： C01B25/231

    CPC分类号： C01B25/222 ,  C01B25/228 ,  C01B25/231

    摘要： The invention relates to a process for producing phosphoric acid, including etching, in an aqueous medium, phosphate rock using sulfuric acid, resulting in the formation of a first dihydrate slurry, in suspension in an aqueous phase, having a free P
    2 O
    5 content of between 38 and 50% and a free SO
    3 content lower than 0.5%, converting said first slurry by means of heating, resulting in the recrystallization of the solubilized calcium sulfate so as to obtain a second hemihydrate slurry, and separating the second slurry into industrial phosphoric acid and a hemihydrate cake, characterized in that said process includes, during the etching, adding a fluorine source into the first slurry with a content of 1 to 5 wt % of F relative to the P
    2 O
    5 contained in the phosphate rock.

    PROCEDE DE PRODUCTION D'ACIDE PHOSPHORIQUE
    8.
    发明公开
    PROCEDE DE PRODUCTION D'ACIDE PHOSPHORIQUE 有权
    用于生产PHOSPHORIC

    公开(公告)号：EP2507168A1

    公开(公告)日：2012-10-10

    申请号：EP10787103.0

    申请日：2010-12-02

    申请人： Prayon Technologies

    发明人： HOXHA, Antoine ,  FATI, Dorina

    IPC分类号： C01B25/231

    CPC分类号： C01B25/231 ,  C01B25/228

    摘要： The invention relates to a method for producing phosphoric acid, including: attacking phosphate rock by means of sulfuric acid between 70º and 90º C with formation of a first calcium sulfate dihydrate crystal slurry, the aqueous acid phase of said slurry having free P
    2 O
    5 content between 38 and 50 wt% and free SO
    3 content that is less than 0.5 wt% and greater than 0.05 wt%; converting said first slurry by means of heating at a temperature greater than 90º C, thus giving rise to a second slurry formed of calcium sulfate hemihydrate crystals; and, within the second slurry, separating a produced phosphoric acid, having a free SO
    3 content that is less than 2%, and a calcium sulfate hemihydrate filter cake.

    PROCEDE DE PREPARATION D'ACIDE PHOSPHORIQUE ET DE SULFATE DE CALCIUM
    10.
    发明公开
    PROCEDE DE PREPARATION D'ACIDE PHOSPHORIQUE ET DE SULFATE DE CALCIUM 失效
    用于生产磷酸和硫酸钙。

    公开(公告)号：EP0169842A1

    公开(公告)日：1986-02-05

    申请号：EP84900958.0

    申请日：1984-03-13

    申请人： Prayon Développement Société anonyme

    发明人： DAVISTER, Armand, Laurent ,  DUBREUCQ, André, Robert ,  THIRION, Francis, Arthur

    IPC分类号： C01B ,  C01F ,  C01B25 ,  C01F11

    CPC分类号： C01B25/228 ,  C01B25/2295 ,  C01F11/466

    摘要： Procédé de préparation d'acide phosphorique et de sulfate de calcium suivant lequel on soumet du phosphate de calcium à une attaque par un mélange d'acides sulfurique et phosphorique comprenant au moins trois étapes de cristallisation successives: une première étape (1) de réaction entre le phosphate (2) et d'acides phosphorique et sulfurique (3 et 4) formant de l'hémihydrate alpha de sulfate de calcium, une deuxième étape (12) recristallisant l'hémihydrate alpha en dihydrate et une troisième étape (18) transformant ce dernier en hémihydrate alpha, anhydrite II ou un mélange de ces deux, celui-ci étant alors soumis à une opération de séparation (22), l'acide phosphorique de production (10) étant soutiré dans la première étape.