Sodium sulfate, a common salt, is a crystalline white ionic substance with a high melting point. It is used as a drying agent in glass manufacturing and organic synthesis, as a chemical analysis reagent and in dyeing textiles.
Sodium sulfate is a natural substance that is present in nature in several forms. Among them are Glauber’s salt (named after Johann Rudolf Glauber, who discovered it in the seventeenth century) and thenardite. These two salts are both soluble in water.
The most common form of sodium sulfate is decahydrate. However, there are also several related hydrates. Sodium sulfate in this form has a melting point of 888degC.
A rarer form is heptahydrate. This has an extremely low BCF value.
Sodium sulfate can be produced from sulfuric acid and sodium chloride. Sulfuric acid is often neutralized by sodium hydroxide. Other methods of production include the Leblanc process, the Hargreaves process, and the Mannheim process. Almost all of the world’s production is natural, though half of it is chemically produced. In 1990, Spain was the largest producer of natural sodium sulfate. During 2006, however, production was estimated to have decreased to 1.5 to 2 million tonnes per year.
Sodium sulfate has a high affinity for various organic compounds. Hence it is a common component in household detergents for textile laundering. Some household detergents contain concentrations of 20.8% to 56.7 percent. While this is a small percentage, it still means that a significant proportion of the domestic consumer population is exposed to sodium sulfate.