Sodium sulfate is the crystalline white solid of formula Na2SO4. It can be naturally found in the form of sulphide minerals and in dissolved form in salt lakes. It can also be artificially produced as the by-product of chemical processes.
Generally, half of the world’s production of this sulfate is from its natural mineral form, known as Glauber’s salt, while the other half comes from chemically produced by-products. The by-products come mainly from the Mannheim process and the Hargreaves process, which produce hydrochloric acid.
This is a highly water-soluble solid that can be used to make a variety of things, including soaps, detergents, glasses and heat storages. The boiling point of the decahydrate is 884 degrees Celsius, making it very useful in passive solar heating systems.
When compared to other acid salts, it has unusual solubility characteristics in water. It can be soluble in water at temperatures as low as 0 degrees, but this solubility drops dramatically as the temperature rises.
It is a very popular ingredient in in-home laundry detergent. It also dissolves organic liquids, and is used in the Kraft process for the manufacture of paper pulp.
Anhydrous sodium sulfate is a white powder with an orthorhombic or hexagonal structure, hygroscopic and has refractive index 1.468. It melts at 884 degrees Celsius and has a density of 2.664 g/cm3. It is soluble in water, insoluble in ethanol. It is odorless and has a bitter and salty taste.