Sulfamic Acid

About This Product

Sulfamic acid, amidosulfonic acid, has the formula H3NSO3 and CAS number 5329-14-6. It is supplied as white, odourless, non-hygroscopic crystals that dissolve readily in water to give a strongly acidic solution. Its commercial position comes from what it lets a plant avoid. Descaling with hydrochloric acid is effective and cheap, but it introduces chloride ions, and chloride is the specific agent responsible for pitting and stress corrosion cracking in austenitic stainless steel. A single aggressive clean can initiate cracking that fails months later, which is why chloride-free descaling is mandated in many stainless and food-contact installations. Sulfamic acid dissolves calcium carbonate, rust and beerstone effectively while introducing no chloride at all. Being a stable, non-volatile, non-fuming solid, it also avoids the fume hazard and the transport and storage burden of a concentrated liquid acid. Two cautions apply: it hydrolyses slowly in hot solution, so hot baths should be made up fresh, and it must not be mixed with hypochlorite, which liberates chlorine gas. It is used in descaling heat exchangers and boilers, dairy and brewery cleaning, cooling tower cleaning, metal pickling, sulfamate electroplating and as a chlorine stabiliser. Bio Green Chem supplies sulfamic acid to specification on assay, moisture, iron, sulfate, insolubles and heavy metals.