What Is Sulfamic Acid?
Sulfamic acid, also called amidosulfonic acid or amidosulfuric acid, is a white, crystalline, non-volatile solid with the formula H3NSO3 (often written NH2SO3H) and a molecular weight of 97.09 g/mol (CAS 5329-14-6). It dissolves readily in water to form a strongly acidic solution, and it is one of the few strong mineral-type acids that is a solid at room temperature, non-hygroscopic and practically odorless. It is stable for years when stored dry, and its aqueous solutions are much less corrosive to metals than hydrochloric or sulfuric acid of equivalent strength, which is why it is a preferred descaling and cleaning agent in industry.
Is Sulfamic Acid Safe for Humans?
No. Sulfamic acid is a corrosive substance and must never be ingested, inhaled as dust or allowed to contact skin or eyes. It is classified as a dangerous good for transport (UN 2967, Class 8 corrosive, Packing Group III) and carries the GHS hazard statement H314, severe skin burns and eye damage. Inhaling the powder irritates the nose, throat and lungs. Ingestion of the material can cause serious gastrointestinal distress and, in severe cases, circulatory collapse and damage to the kidneys, liver and heart, so any suspected ingestion requires immediate medical attention. Sulfamic acid is a powerful industrial chemical for trained personnel, not a household-safe product.
Sulfamic Acid Specifications (CAS 5329-14-6)
| Parameter | Value |
|---|---|
| CAS number | 5329-14-6 |
| Molecular formula | H3NSO3 (NH2SO3H) |
| Molecular weight | 97.09 g/mol |
| Appearance | White orthorhombic crystals |
| Melting point | About 205 °C (decomposes on further heating) |
| Density | About 2.15 g/cm³ |
| Solubility | Freely soluble in water and liquid ammonia; slightly soluble in methanol; insoluble in ethanol and ether |
| UN number / class | UN 2967, Class 8, Packing Group III |
| HS code | 2811199090 |
Safe Handling and First Aid
Always wear goggles or a face shield, chemically resistant gloves and protective clothing when handling sulfamic acid, and use dust control or respiratory protection where powder is generated. Work in a well-ventilated area and keep the product away from incompatible materials, especially strong oxidizers, bases and metals such as aluminum in confined systems.
Skin contact: remove contaminated clothing and rinse the skin with plenty of water for at least 15 minutes.
Eye contact: rinse with water for at least 15 minutes, lifting the eyelids, and seek medical attention.
Inhalation: move to fresh air and get medical help if symptoms persist.
Ingestion: do not induce vomiting; rinse the mouth and contact a poison center or physician immediately.
Main Industrial Uses of Sulfamic Acid
Descaling and cleaning: removal of limescale, rust and mineral deposits from boilers, heat exchangers, cooling towers, evaporators and dairy and brewery equipment, with lower metal corrosion than many strong acids.
pH adjustment: a safe-to-handle solid acid for neutralizing alkaline systems and for pH control in swimming pools and industrial baths.
Chemical synthesis: a raw material for sulfamate esters, sulfamates and sweetener intermediates such as acesulfame-type compounds, and a catalyst in esterification and nitrite reactions.
Other applications: dye and pigment processing, electroplating baths, paper and textile finishing, and cleaning formulations for ceramics, tiles and metals.
Frequently Asked Questions
Is sulfamic acid safe to touch? No. It is corrosive (H314) and will burn skin and eyes on contact. Always wear gloves and goggles when handling the powder or its solutions.
What is sulfamic acid used for? It is mainly used for descaling boilers, heat exchangers and industrial equipment, for pH adjustment, and as a chemical intermediate in sulfamate and sweetener production.
Is sulfamic acid the same as sulfuric acid? No. Sulfamic acid is a solid, less corrosive amide of sulfuric acid. Its solutions are milder on metals, which is why it is preferred for cleaning equipment that sulfuric acid would attack.
Can sulfamic acid be used in food? Sulfamic acid itself is not a food additive; it is an industrial cleaning and synthesis chemical. Food-contact use is limited to cleaning agents that are thoroughly rinsed and meet applicable residue regulations.
How is sulfamic acid packaged for export? Typical packaging is 25 kg woven bags with inner liners, or drums, on pallets, shipped under UN 2967 Class 8 rules with SDS and COA documentation.
What should I do if someone ingests sulfamic acid? Do not induce vomiting. Rinse the mouth, give water if the person is conscious, and contact emergency medical services immediately with the SDS in hand.