sodium sulphate anhydrous for paper production CAS 7757-82-6

Anhydrous sodium sulfate, commonly known as Glauber's salt anhydrous or thenardite, is an inorganic compound with the chemical formula Na₂SO₄ and CAS number 7757-82-6. It typically exists as a white, odorless, crystalline powder or granular solid that is highly soluble in water—its solubility increases significantly with rising temperature, and it absorbs small amounts of moisture from the air without deliquescing.
Industrially, it is produced through two main methods: one is the dehydration of mirabilite (hydrated sodium sulfate, Na₂SO₄·10H₂O) by heating, and the other is the by-product recovery from chemical processes like the production of hydrochloric acid or titanium dioxide.
It has a wide range of applications across sectors:
In the textile and dyeing industry, it acts as a leveling agent to help dyes adhere evenly to fabrics (such as cotton, linen) and improve color fastness;
In the paper industry, it is used in pulp cooking to enhance pulp yield and fiber quality;
In the chemical industry, it serves as a raw material for manufacturing sodium sulfide, sodium silicate, and other chemicals, and also as a drying agent for organic solvents;
In agriculture, it can be used as a trace element fertilizer to supplement sulfur and sodium for certain crops (e.g., sugar beets) in sulfur-deficient soils;
It also finds use in the pharmaceutical, glass, and detergent industries.
Anhydrous sodium sulfate is chemically stable under normal conditions, non-toxic, and non-corrosive, making it easy to store and transport when kept in a dry environment.