Process of preparing oxalic acid by calcium sulfate cycle method

Process of preparing oxalic acid by calcium sulfate cycle method

  • CN 101,012,165 B
  • Filed: 02/09/2007
  • Issued: 07/18/2012
  • Est. Priority Date: 02/09/2007
  • Status: Active Grant
First Claim
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1. the technology of a preparing oxalic acid by calcium sulfate cycle method is characterized in that:

  • (1), in the sodium oxalate aqueous solution, add excess sulfuric acid calcium makes itself and sodium oxalate reaction back generate calcium oxalate precipitation and aqueous sodium persulfate solution, at this moment the excessive 200-1000% of calcium sulfate;

    (2), with said mixture through liquid-solid separation, aqueous sodium persulfate solution after concentrating the sodium sulfate industrial goods;

    (3), with the caoxalate that obtains after the above-mentioned separation and calcium sulphate solid mixture after washing, drop in the acidolysis still, add water and fully stir, form suspension-s;

    (4), in the above-mentioned aaerosol solution that contains caoxalate and calcium sulfate, add the normal vitriol oil, generate oxalic acid aqueous solution and calcium sulfate precipitation;

    (5), with the liquid-solid separation of said mixture, liquid phase draws finished product oxalic acid crystal through evaporation concentration, crystallization, drying, still contains a small amount of oxalic acid in the calcium sulphate solid, but need not washing, directly returns in the above-mentioned steps (1) and recycles.

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