Sulphamic Acid

Sulfamic acid is a molecular compound. This colorless, water-soluble compound has many applications. Sulfamic Acid is produced industrially by treating urea with a mixture of Sulfur Trioxide and Sulphuric Acid (or oleum).

Synonyms: Amidosulfonsäure, Sulfaminsäure, Amidosulfonic Acid, Amidosulfuric Acid, Amiosulfonic Acid, Sulfamic Acid, Sulfamidic Acid
Chemical Formula: H3NSO3
CAS Number: 5329-14-6

Characteristics

Molar Weight: 97.10 g/mol

Melting Point: 205 °C

Density: 2.15 g/cc

Forms: Powder, White, Crystalline

Uses and Applications

Key applications

Plating
Cleaning products
Corrosion inhibitor and anti-scaling agent
Pulp and paper
Bleaching agent
Electroplating

Industries

General information about sulphamic acid

Sulphamic acid, also known as amidosulphonic acid or amidosulphuric acid, is an inorganic compound that does not occur in nature and is only synthesised industrially. It is used in various industries for surface preparation and is mainly used as a descaling agent.

Properties of sulphamic acid

Amidosulfonic acid is a colourless to whitish-yellow, odourless crystalline compound. It is not hygroscopic, i.e. it does not bind moisture from the environment. It is the monoamide of sulphuric acid. The salts of amidosulfonic acid are called amidosulfonates or sulfamates.

Amidosulfonic acid melts at 205 °C with incipient decomposition and heavy smoke development. The substance is poorly soluble in most organic solvents, but readily soluble in water. The dissolved crystals react acidically.

Amidosulfonic acid (+H3N-SO3-) is a zwitterion, i.e. a compound that has two or more functional groups. The charge of one functional group is positive and the charge of the other is negative.

Amidosulphonic acid is produced from urea, sulphuric acid and disulphuric acid.

Amidosulfonic acid in the construction industry

Amidosulfonic acid is used in the construction industry to clean concrete mixers, concrete pumps and other concrete processing equipment. It efficiently removes concrete and limescale deposits and is popular due to its comparatively low corrosiveness towards metals compared to other strong acids, as it does not damage the equipment used.

Amidosulfonic acid is also used for surface preparation. Before applying coatings such as paints or varnishes, the substance is used to remove impurities, rust and limescale deposits from the surface and to etch it. This ensures better adhesion of the coatings. The acid is also used to clean masonry.

In water-bearing systems and heating systems installed in buildings, amidosulfonic acid is used to remove limescale deposits. This improves the efficiency and service life of the systems.

Layers of various colored papers in stack close-up view

Amidosulfonic acid in the paper industry

In the paper industry, amidosulfonic acid removes limescale deposits and other residues from boilers, evaporators, water treatment systems and other machinery in paper mills. It is also used as a bleaching agent for paper and in some paper manufacturing processes to regulate the pH value.

Other areas of application for amidosulfonic acid

Alongside phosphoric and citric acid, amidosulfonic acid is an important component of descaling agents and sanitary cleaners in the cleaning industry.

Amidosulfonic acid is also relevant in the automotive and metalworking industries. It ensures the effective cleaning (especially the removal of limescale and rust) and preparation of surfaces, thus ensuring that coatings adhere optimally and can fulfil their protective function. The acid is also used to clean coating systems and equipment.

In laboratories, amidosulfonic acid is used as a primary titer substance and to destroy nitrite; in electroplating, it is used to adjust the pH value of nickel sulfamate baths. In addition, a solution of amidosulphonic acid with sodium lauryl sulphate is used to activate a nickel layer.