Abstract: A process for decolorizing a cellulose textile bearing oxidized vat dye comprising contacting the cellulose textile with an aqueous solution of hydrogen peroxide containing an amount of a hydrogen peroxide catalyst sufficient to oxidize vat dye in the fabric until the dye is decolorized by oxidation. Then the cellulose textile is separated from the aqueous solution. The hydrogen peroxide catalyst can be a water-soluble lower alkyl quaternary amine salt such as a dihydroxypropyltrimethylammonium halide, chlorohydroxypropyltrimethylammonium halide or epoxypropyltrimethylammonium halide, or it can be a transition metal ion such as a cupric or stannous metal ion present in an amount of from 0.1 to 2 ppm. The process is suitable for decolorizing denim bearing vat dyes such as indigo, and is particularly suitable for decolorizing denim scrap.

Abstract: A process for recovering a vat dye from a textile using a heated organic solvent. The textile is contacted with a heated organic solvent in which the dye is soluble until dye is extracted from the textile into the solvent to produce a dye-containing solvent solution. The dye is then recovered from the organic solvent by evaporation of the solvent leaving a dye residue, cooling and precipitation of the dye, or extraction of the dye by contacting the dye-containing solvent solution with an aqueous solution containing a reducing agent for the dye. When dye is extracted from the dye-containing solvent solution by contacting it with an aqueous solution containing a reducing agent, the dye is subsequently insolubilized by oxidation, and the dye is recovered from the aqueous dye solution. This process is particularly advantageous for recovering indigo dye from denim scrap.