Process for the exhaustive removal of chromium totalen wastewater of dye baths with mordant dyestuffs tes

摘要

In the process of dyeing with mordant dyes and a chromating agent, soluble thiosulphate is incorporated at the same time as, or after, the addition of the chromating agent, at pH 3-4 to leave the eventual spent bath depleted in chromium, and substantially free from Cr6+. The soluble thiosulphate may be an alkali metal or ammonium thiosulphate.