Industrial production sulfate decomposition

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. 

Effect of sulfides. Sulfides are present in polluted water either as industrial effluent or when water conditions support the growth of sulfate-reducing bacteria. They can also occur in stagnant seawater by decomposition of organic matter to sulfides and ammonia. Sulfides form a black corrosion product that is less adherent and protective than the normal oxide film. Under susceptible conditions, unwanted pitting or accelerated general corrosion may occur. 

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