Sodium sulfate (also known as sodium sulphate or sulfate of soda) is the inorganic compound with formula Na2SO4 as well as several related hydrates. All forms are white solids that are highly soluble in water. It is mainly used for the manufacture of detergents and in the kraft process of paper pulping.

It serves as the filled material in composing the cleaner. In paper making industry, it serves as atmometer when it used to make sulfate paper pulp. In glasses industry, it usually replaces for pure alkali. In chemical industry, it used to make sodium sulfate, sodium silicate and other chemical raw material. In weaving industry, it used to prepare concreting of Wei Ni Lun Silk. In medicine industry, it serves as delayed evacuant. It also used in metallurgy and leather industry.