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Process for recovering organic acids from bleaching liquors

  • US 6,923,888 B2
  • Filed: 02/27/2001
  • Issued: 08/02/2005
  • Est. Priority Date: 02/28/2000
  • Status: Expired due to Term
First Claim
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1. A process for treating bleaching liquors from pulping processes based on organic acids, the process comprising cooking with organic acids and bleaching of pulp, and further comprising(a) adding inorganic acid selected from nitric acid, phosphoric acid and/or sulphuric acid to bleaching liquor obtained as a result of bleaching or a stage closely associated with bleaching;

  • (b) separating the organic acids from the bleaching liquor and recycling the same to cooking to be used as cooking chemicals; and

    (c) recovering the nitrogen-, phosphor- and/or sulphur-containing product thus obtained, from which organic acids have been separated, to be used as a fertilizer or as raw material for a fertilizer.

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