Treatment of dye wastes
AssigneeDart Industries Inc.
InventorLeslie Emery Lancy
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Abstract
A process is disclosed for the removal of colorants from industrial dye waste solutions which involves the treatment of the waste with a solution of a Group IA or IIA metal halide or sulfate to precipitate the colorant, which subsequently is removed by common solid separation techniques as a dense material of relatively high solids content. The process is particularly suitable for integration into a dyeing process to increase color fastness of the dyed article.
Claims10
In a dyeing process for the production of color fast dyed textile articles wherein an undyed article is immersed in a dye bath for absorption of dye into its pores, and the dyed article having excess dye solution adhering to its surfaces is removed from said dye bath, the improvement which comprises:
- contacting the removed article and the excess dye solution adhering thereto in a precipitation zone with an aqueous solution of a salt selected from halides or sulfates of metals of Group IA or Group IIA of the Periodic Chart in amounts such that the concentration of salt in the precipitation zone is at least 100 grams per liter of total liquid to precipitate the dye absorbed in the pores, to rinse the excess dye from the article and to precipitate said excess dye;
- separating the precipitated dye from the aqueous salt solution substantially free of color,
- recovering the aqueous salt solution for reuse in the precipitation zone, and
- recovering a color fast dyed textile article.
Dependencies are inferred from the claim text.