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    2.
    发明专利
    未知

    公开(公告)号：DE1592778A1

    公开(公告)日：1971-02-18

    申请号：DEST022812

    申请日：1964-10-13

    Applicant: STAMICARBON

    Inventor： DINGEMANS SIMON ,  SLOT WILEM

    IPC: C05B7/00 ,  C05B11/06

    Abstract: In a process for the preparation of fertilizers containing ammonium phosphate, a calcium nitrate solution produced by the action of a nitric acid containing solution on rock phosphate is reacted in a first reaction zone with a solution containing ammonium and/or potassium sulphate the reactants being in a ratio such that more than 0.8 mol of soluble calcium salt is present per mol of sulphate, holding the precipitate formed in suspension in the mother liquor in a second reaction zone for at least 10 minutes while a filterable gypsum ppt. forms, removing the ppt. and adding ammonia to the mother liquor to reduce its acidity and further processing the mother liquor in known fashion by removal of water and, if desired, addition of other substances, to produce the ammonium phosphate product. The residence time in first reaction zone and the second reaction zone are preferably at least 5 and 15 minutes respectively, and the preferred ratio of Ca/SO4 in the first reaction zone is between 1 and 1.1. The temperature of the two zones is kept between 15 DEG and 60 DEG C., preferably 25 DEG and 35 DEG C., and part of the gypsum suspension produced, e.g. 1 to 1.5% by weight, is fed back to the sulphate solution.

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