Sulphamic Acid (Sulfamic) - Descaler / Rust Remover


SKU: RD11263

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Technical grade

Descaler, Cleaner, Rust & Limescale Remover

Sulphamic acid also called sulfamic acid is a white crystalline solid which is stable and non-hygroscopic. It is soluble in water and formamide and slightly soluble in methanol, ether, acetone and concentrated sulphuric acid. It is classified as a strong inorganic acid and is commercially produced from urea and fuming sulphuric acid. At room temperature, dilute aqueous sulphamic acid solution is stable for a long time but rapid hydrolysis occurs at elevated temperatures. It's solution is less corrosive toward metals than other mineral acids like hydrochloric acid. Sulfamic acid possesses a scale solubilising capacity which makes it ideal for removal of scale from boilers, cooling towers, coils, heat exchangers, condensers and a wide range of heating and cooling systems thereby increasing the efficiency of plant and equipment.

Sulphamic acid is used as an acidic cleaning agent, typically for metals and ceramics. It is a replacement for hydrochloric acid for the removal of rust. In households, it is often found as a descaling agent in detergents, cleaners and toilet cleaners for the removal of limescale.

Properties of Sulphamic acid

  • Synonyms: sulfamic acid; Amidosulfonic acid; Amidosulphonic acid; sulphamidic acid;
  • CAS No: 5329-14-6
  • EINECS No: 226-218-8
  • Appearance: white crystalline solid
  • Molecular formula: NH2SO3H
  • Molar mass: 97.09 g/mol
  • Density: 2.15g/cm3
  • Solubility in water: 213 g/L (20C)
  • Melting point: 190 - 225 C
  • Boiling point: decomposes
  • pH: 1.2 (1% solution @ 20C)
  • Refractive index: 1.553


  • Descaler, Cleaner & Rust Remover
  • removing excess grout on tiles, efflorescence and other mineral deposits
  • Cleaner & descaler for Dairy equipment (pipeline milkers, milk evaporators)
  • Cleaner & descaler for Brewery equipment (pipelines, Vats, etc)
  • Catalyst for esterfication process process
  • Used in dye and pigment manufacture
  • Used as a herbicide
  • Effecticve against Foot and Mouth (approved bty Defra)
  • Ingredient in Denture Tablets
  • Coagulator for urea-formaldehyde resins
  • Ingredient in fire extinguishing media
  • Pulp and paper industry as a chloride stabilizer
  • Synthesis of nitrous oxide by reaction with nitric acid

Sulphamic acid in descaling

Sulfamic Acid is super efficient descaling agent and is used for cleaning a variety of industrial equipment and domestic appliances. It is used for cleaning boilers, heat exchangers, condensers, jackets and coils, descaling toilets, removing excess grout on tiles, efflorescence and other mineral deposits etc (See below for details on how to use). It helps remove hard water scale, protein deposits, beer and milk stone, light rust and copper corrosion

Sulphamic acid in paper & pulp Industry

Sulphamic Acid prevents pulp degradation due to temperature at the chlorination and hydrochloride stage. It permits bleaching at higher temperature and lower pH without loss of strength.

Sulphamic acid is used in manufacturing of Dyes, Pigments and in the dyeing of leather

Sulfamic Acid removes excess of nitrides used in the diazotization reactions in the manufacturing of dye stuffs and pigments. Nitrides if present in process water of effluents can also be removed by using Sulphamic Acid

Sulphamic acid in Chlorine Stabilization

Sulphamic Acid is used for stabilizing chlorine in swimming pools and cooling towers.

Sulphamic acid in Electroplating and Electro-refining


Sulphamic acid in Sulphation and Sulphamation

Sulfamic acid is used for sulphation and sulphamation of many organic compounds.


How to use Sulphamic Acid for cleaning & descaling:

For removing excess grout from tiling or dissolving efflorescence from walls, floors etc: Make up a solution of sulphamic acid by dissolving 80-100g per litre of warm water. Apply to surface using a cloth or brush and allow to work for a few minutes. Agitate with brush if necessary and rinse with clean water. Please Note: if using around coloured grout use a weaker solution of approx 2% (20g per litre of water) to reduce the risk of leaching out any colour from the grout.

For descaling equipment use a 10% solution. Sulphamic acid is safe for steel, iron, glass and wood equipment, and may be used with caution on copper, aluminium, and galvanized metal surfaces. Clean in a soak tank or by circulation. For surfaces, apply to surface using a cloth or brush and allow to work for a few minutes. Agitate with brush if necessary and rinse thoroughly with clean water.

For Boiler systems & Cooling Towers use a circulation treatment of a 10% to 15% solution depending on how bad the system is. Before applying flush out system and refill with clean water. Determine the volume of water and mix in the sulphamic acid at a rate of 100g to 150g per litre of water. It may be necessary to add a corrosion inhibitor to help protect mild steel, brass, copper and stainless steel from acid attack. Circulate the solution at room temperature or heated to a maximum of 60C for heavier cleaning for several hours until desired results are achieved. Note: Do not use at boiling point or product will undergo hydrolysis and will not work. Do not use on galvanised materials, zinc or aluminium. Sulphamic acid will not remove silica or calcium phosphate scales. After cleaning rinse thoroughly and check system. Neutralise with 1 to 2% sodium carbonate solution (soda ash) with a target pH of 6 to 8 or whatever discharge pH range applies.

Repeat applications may be necessary for heavily soiled systems. After cleaning Periodic flushing of the system to remove loosened scale and contaminants will be necessary.

For rust removal use a solution of 10%-20%.

Health & Safety

R-phrase(s): R36/38 Irritating to eyes and skin. R52/53 Harmful to aquatic organisms, may cause long-term adverse effects in the aquatic environment.

S-phrase(s): S26 In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S28 After contact with skin, wash immediately with plenty of soap and water. S61 Avoid release to the environment. Refer to special instructions/ Safety data sheets.

Click here to view MSDS

Click here for Sales Specification sheet


 PLEASE NOTE: This product is not for human or animal consumption.