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    Process for the preparation of chromic acid
    11.
    发明授权
    Process for the preparation of chromic acid 失效
    制备色素的方法

    公开(公告)号：US5096548A

    公开(公告)日：1992-03-17

    申请号：US626076

    申请日：1990-12-11

    申请人： Norbert Lonhoff ,  Ludwig Schmidt ,  Hans-Dieter Block ,  Rainer Weber

    发明人： Norbert Lonhoff ,  Ludwig Schmidt ,  Hans-Dieter Block ,  Rainer Weber

    IPC分类号： C25B1/00 ,  B01J47/12 ,  C01G37/033 ,  C25B1/22 ,  C25B15/08 ,  C25C1/10

    CPC分类号： C01G37/033 ,  C25B1/22 ,  C25C1/10

    摘要： A process for the production of chromic acid, comprising(a) dissolving ferrochrome in sulphuric acid and mother liquor from the subsequent crystallization of ammonium chrome alum, optionally with the addition of at least one of catholyte and anolyte overflow from the subsequent electrolysis,(b) removing undissolved constituents by filtration,(c) removing dissolved iron by the addition of at least one of ammonia and ammonium sulphate to the filtrate obtained, crystallizing iron ammonium sulphate and filtering,(d) crystallizing and filtering ammonium chrome alum from the remaining solution and returning the filtrate for dissolving ferrochrome in step (a),(e) dissolving the ammonium chrome alum in water,(f) precipitating and separating chromium-(III) hydroxide from the resulting solution by adding a base, optionally under reducing conditions,(g) dissolving the separated chromium hydroxide in chromic acid and optionally sulphuric acid so that either a single solution in chromic acid is obtained or two solutions are obtained, one in chromic acid and another in sulphuric acid,(h) separating the solution(s) from undissolved constituents, and(i) utilizing the solution of chromium hydroxide in chromic acid as anolyte in the electrolytic production of chromic acid in an electrolytic cell divided by a membrane, and either utilizing the same solution as catholyte in the above mentioned electrolytic cell divided by a membrane or utilizing the solution of chromium hydroxide in sulphuric acid as catholyte in the above mentioned electrolytic cell divided by a membrane, hydrogen and metallic chromium being deposited electrolytically at the cathode and/or chromium (II) ions being produced electrolytically at the cathode.

    摘要翻译： 一种生产铬酸的方法，包括（a）将铬铁铬酸盐和母液从随后的铵铬明矾结晶中溶解，任选地从随后的电解中加入至少一种阴极电解液和阳极电解液溢出物（b ）通过过滤除去未溶解的组分，（c）通过向所得滤液中加入至少一种氨和硫酸铵除去溶解的铁，结晶硫酸铁铵并过滤，（d）从剩余溶液中结晶并过滤铵铬明矾 并在步骤（a）中返回用于溶解铬铁的滤液，（e）将铵铬明矾溶解在水中，（f）通过加入碱（任选在还原条件下）将所得溶液中的铬 - （III） （g）将分离的氢氧化铬溶解在铬酸和任选的硫酸中，使得单一的铬酸溶液 得到两种溶液，一种在铬酸中，另一种在硫酸中，（h）将溶液与未溶解的组分分离，和（i）在电解生产中利用铬酸中的铬酸溶液作为阳极电解液 在由电解槽中分离的膜中的铬酸，或者利用与上述电解槽中的阴极电解液相同的溶液，或者利用氢氧化铬溶液作为阴极电解液，除去上述电解槽 在阴极处电解沉积的阴极和/或铬（II）离子沉积的膜，氢和金属铬。

    Processes for the preparation of alkali metal dichromates and chromic acid
    14.
    发明授权
    Processes for the preparation of alkali metal dichromates and chromic acid 失效
    制备碱金属二铬酸盐和铬酸的方法

    公开(公告)号：US5094729A

    公开(公告)日：1992-03-10

    申请号：US659435

    申请日：1991-02-22

    申请人： Helmut Klotz ,  Hans D. Pinter ,  Rainer Weber ,  Hans-Dieter Block ,  Norbert Lonhoff

    发明人： Helmut Klotz ,  Hans D. Pinter ,  Rainer Weber ,  Hans-Dieter Block ,  Norbert Lonhoff

    IPC分类号： C01G37/14 ,  C25B1/14 ,  C25B1/22

    CPC分类号： C25B1/22

    摘要： A process for the preparation of alkali metal dichromates and chromic acid by the electrolysis of monochromate and/or dichromate solutions in an electrolytic cell in which the anode and cathode chamber are separated by a cation exchanger membrane anolyte fluid containing dichromate and/or chromic acid being formed in the anode chamber and alkaline catholyte fluid containing alkali metal ions being formed in the cathode chamber, the improvement wherein the catholyte fluids are periodically replaced by a solution which is at a pH below 6.

    摘要翻译： 通过在电解池中电解单色和/或重铬酸盐溶液来制备碱金属重铬酸盐和铬酸的方法，其中阳极室和阴极室由含有重铬酸盐和/或铬酸的阳离子交换膜阳极电解液分离， 形成在阳极室中，并且在阴极室中形成含有碱金属离子的碱性阴极电解液，其中阴极电解液周期性地被pH低于6的溶液所取代。

    Process for the preparation of chromic acid
    15.
    发明授权
    Process for the preparation of chromic acid 失效
    制备色素的方法

    公开(公告)号：US5181994A

    公开(公告)日：1993-01-26

    申请号：US625715

    申请日：1990-12-11

    申请人： Norbert Lonhoff ,  Ludwig Schmidt ,  Hans-Dieter Block ,  Rainer Weber

    发明人： Norbert Lonhoff ,  Ludwig Schmidt ,  Hans-Dieter Block ,  Rainer Weber

    IPC分类号： C25B1/00 ,  B01J47/12 ,  C01G37/033 ,  C25B1/22 ,  C25B15/08 ,  C25C1/10

    CPC分类号： C25C1/10 ,  C01G37/033 ,  C25B1/22

    摘要： A process for the production of chromic acid, comprisinga) dissolving ferrochrome in sulphuric acid, optionally with the addition of catholyte and/or anolyte overflow from the electrolysis,b) removing undissolved constituents by filtration,c) adding a reducing agent in a quantity more than equivalent to the quantity of iron(III) and chromium(IV) in the solution,d) precipitating chromium(III) hydroxide by raising the pH to about 4-6 by the addition of a base while maintaining the reducing conditions in the solution,e) separating the precipitated chromium hydroxide while maintaining the reducing conditions,f) working up the aqueous solution containing iron by oxidation; precipitating iron(III) hydroxide or iron(III) oxide and optionally isolating the sulphate in the solution as sodium sulphate, ammonium sulphate or calcium sulphate,g) dissolving the separated chromium hydroxide in chromic acid and optionally sulphuric acid where either a single solution in chromic acid is produced or two solutions are produced, one in chromic acid and another in sulphuric acid,h) separating the solution(s) from undissolved constituents andi) employing the chromium hydroxide solution in chromic acid as anolyte in the electrolytic production of chromic acid in an electrolytic cell divided by a membrane, and either using the same solution as catholyte in the electrolytic cell divided by a membrane or using the chromium hydroxide solution in sulphuric acid as catholyte in the electrolytic cell divided by a membrane, hydrogen and/or metallic chromium being deposited electrolytically at the cathode and/or chromium(II) ions being produced electrolytically.

    摘要翻译： 一种生产铬酸的方法，包括：a）将铬铁溶解在硫酸中，任选地从电解中加入阴极电解液和/或阳极电解液溢出物，b）通过过滤除去未溶解的组分，c）加入一定量的还原剂 大于等于溶液中铁（III）和铬（IV）的量，d）通过加入碱将pH升高至约4-6，沉淀出氢氧化铬（III），同时保持其中的还原条件 e）在保持还原条件的同时分离沉淀的氢氧化铬，f）通过氧化处理含铁的水溶液; 沉淀氧化铁（III）或氧化铁（III），并任选地将溶液中的硫酸盐分离为硫酸钠，硫酸铵或硫酸钙，g）将分离的氢氧化铬溶解在铬酸和任选的硫酸中， 产生铬酸或产生两种溶液，一种在铬酸中，另一种在硫酸中，h）将溶液与未溶解的组分分离，以及i）在铬酸的电解生产中使用铬酸中的氢氧化铬溶液作为阳极电解液 在电解槽中除以膜，在电解槽中用阴离子电解液分隔膜或使用硫酸中的氢氧化铬溶液作为阴极电解液，在电解槽中被膜，氢和/或 阴极电解沉积的金属铬和/或电解产生的铬（II）离子。