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    Extraction of phosphoric acid at saline solutions state
    4.
    发明授权
    Extraction of phosphoric acid at saline solutions state 失效
    在海水溶液状态下提取磷酸

    公开(公告)号：US3767769A

    公开(公告)日：1973-10-23

    申请号：US3767769D

    申请日：1971-07-07

    Applicant: PECHINEY SAINT GOBAIN ,  UCB SA

    Inventor： WINAND L ,  GORET J

    IPC: C01B25/30 ,  C01B25/28 ,  C01B25/40 ,  C01B25/46 ,  C01B15/16 ,  C01B25/26

    CPC classification number: C01B25/46 ,  C01B25/28 ,  C01B25/405

    Abstract: A CONTINUOUS PROCESS FOR EXTRACTING ALKALI PHOSPHATES AS CONCENTRATED, PURE SOLUTIONSDERVIED FROM THE ACIDIC ATTACK ON NATURAL ROCK COMPRISING IN T HAT IN A FIRST SERIES OF COUNTERCURRENT FLOW EXTRACTORS IMPURE SOLUTIONS OF PHOSPHORIC ACID ARE TREATED WITH A SOLVENT WHILE A STRONG ACID IS INTRODUCED AT ONE OR MORE POINTS IN THE FIRST SERIES OF EXTRACTORS, EXTRACTING THE SOLUTION OF PHOSPHORIC ACID IN SAID SOLVENT IN COUNTERCURRENT FLOW WITH AQUEOUS SOLUTIONS C ONTAINING PHOSPHATE IONS AND ALKALI IONS WITHIN A SECOND SERIES OF COUNTERCURRENT FLOW EXTRACTORS, FIRST WASHING AND PARTIALLY EXTRACTING THE SOLUTION OF PHOSPHORIC ACID IN SAID SOLVENT WITH A STREAM OF PURE WATER IN A THIRD SERIES OF COUNTERCURRENT FLOW EXTRACTORS, ADDING THE WATER STREAM LOADED WITH PHOSPHORIC ACID TO THE STARTING IMPURE SOLUTIONS OF PHOSPHORIC ACID IN THE FIRST SERIES OF EXTRACTORS, RECYCLING THE SOLVENT LEAVING THE SECOND SERIES OF EXTRACTORS TO THE FIRST SERIES OF EXTRACTORS, COLLECTING EXHAUSTED SOLUTIONS OF PHOSPHORIC ACID CONTAINING THE STRONG ACID WHICH HAS BEEN ADDED AT THE OUTLET OF THE FIRST SERIES OF EXTRACTORS, AND COLLECTING PURE ALKALI PHOSPHATES AS CONCENTRATED SOLUTIONS AT THE OUTLET OF THE SECOND SERIES OF EXTRACTORS.

    Continuous process for the preparation of maleic anhydride from an aqueous solution of maleic acid by distillation
    5.
    发明授权
    Continuous process for the preparation of maleic anhydride from an aqueous solution of maleic acid by distillation 失效
    通过蒸馏从马来酸的水溶液中制备马来酸酐的连续方法

    公开(公告)号：US3642829A

    公开(公告)日：1972-02-15

    申请号：US3642829D

    申请日：1970-01-27

    Applicant: UCB SA

    Inventor： WEYENS ERNEST

    IPC: C07D307/60 ,  C07C51/31 ,  C07C51/56 ,  B01D3/34 ,  C07C57/14

    CPC classification number: C07C51/313 ,  C07C51/56 ,  C07C57/145

    Abstract: CONTINUOUS PROCESS FOR THE PREPARATION OF MALEIC ANHYDRIDE WHICH COMPRISES: (A) CONCENTRATING A MALEIC ACID SOLUTION (E.G. FROM WASHING EFFUENT OF CATALYTIC OXIDATION OF BENZENE) AT 100-150*C. AND 400-760 MM. HG; (B) CONVERTIG THE DEHYDRATED MALEIC ACID FROM (A) AT 150-200*C. AND 40-300 MM. HG INTO A LIQUID PHASE OF IMPURE MALEIC ACID AND A PURIFIED GASEOUS PHASE OF MALEIC ANHYDRIDE AND WATER VAPOUR; (C) TREATING THE LIQUID PHASE FROM (B) WITH MALEIC ACID, FILTERING OFF THE IMPURITIES INCLUDING ANY FUMARIC ACID AND EITHER RECYCLING THE PURIFIED MALEIC ACID FILTRATE PARTLY TO (A) AND PARTLY TO (B) OR REMOVING SAID FILTRATE FORM THE SYSTEM; (D) CONDENSING THE GASEOUS PHASE FORM (B) AT A TEMPERATURE ABOVE THE DEWPOINT OF WATER GIVING SUBSTANTIALLY PURE MALEIC ANHYDRIDE AND WASHING THE RESIDUAL VAPOUR WITH WATER AND EVENTUALLY RECYCLING THE SOLUTION CONTAINING MALEIC ACID TO (A).

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