Chromium sulfate, leather processing

EXPOSURE ROUTES wind transport from road dust wood treated with copper dichromate leather tanned with chromic sulfate chromate production stainless-steel production chrome plating working in tanning industries chromium waste disposal sites chromium manufacturing and processing plants consumption of food and drinking water inhalation of air... 

Different trivalent chromium products, chromium oxide, chromium hydroxide and chromium sulfate, are made by reduction of dichromate. Chromium sulfate is used in leather tanning. Skins are mainly derived from animals that are butchered for the food industry. To protect the skin from putrefaction it is transformed to leather by the tanning process. The tanning agent is fixed to the reactive groups of collagen, the protein in the sldn. That stops the spontaneous decomposition of collagen. 

Hydrolysed, polynuclear Cr complexes are of considerable commercial importance in the dying and tanning industries. In the former the role is that of a mordant to the dye. In leather production it is necessai to treat animat hides to prevent putrefaction and to render them supple when dry. Traditionally, tannin was used, hence the name of the process, but this was superseded towards the end of the nineteenth century by solutions of chromium(lil) sulfate. After soaking in sulfuric acid the hides are impregnated with the Cr solution. This is subsequently made alkaline, when the polynuclear complexes form and bridge... 

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