Sodium sulphate occurs in nature as Glauber’s salt which exists as the mineral mirabilite and the anhydrous form is from the mineral thenardite. It is named after Johann Glauber, who discovered it in the 17th century.

Properties of Sodium sulphate:

  • Sodium sulphate is a white, crystalline solid at room temperature.
  • Sodium sulphate is a stable inorganic salt chemical compound.
  • Sodium sulphate is not decomposes under heating.
  • Sodium sulphate is not reacts with oxidising or reducing agents in normal conditions.
  • Sodium Sulphate is a neutral salt with a pH of 7 as it is derived from strong acid and a strong base.

Production of Sodium Sulphate:

Sodium sulphate anhydrous, is obtained from Thenardite. It occurs naturally over millions of years through the erosion of igneous rocks. When the igneous rocks are eroded by friction, the sodium in the rocks is carried by water, and then deposited in natural basins. They slowly react with sulphur present in the atmosphere to give rise to a sodium sulphate precipitate. It was initially isolated from spring water in 1604, by Glauber. It was initially used as a laxative as it had excellent applications as a laxative.

Sodium sulphate has many uses as it is inexpensive and easily available. Some of the different applications of the salt are:

Detergent Industry
Sodium sulphate is majorly used as a filler in powdered laundry detergents.

Paper Industry
Sodium sulphate is utilized in the Kraft process for the manufacture of wood pulp. The wood chips loaded by sodium sulphate are heated, that breaks the bond in cellulose of the wood, therefore the wood chips become soft and easily form into wood pulp.

Glass Industry
Sodium sulphate is used in the glass industry. It is used as a fining agent, to help remove small air bubbles from molten glass. Apart from that, it also fluxes the glass and prevents scum formation of the glass melt, during refining.

Textile Industry
Glaubler salt is used in the textile industry for the manufacturing of textiles as it helps in leveling, reducing negative charges on fibres and ensure that the dyes penetrate evenly. It is preferred over its alternatives as it does not corrode the stainless steel vessels used in dyeing.

Other applications
Glauber salt is now being proposed for providing heat storage in passive solar heating systems because of its exceptional solubility properties and its high heat of crystallisation. Sodium sulphate is used in the laboratory, as a drying agent for organic solutions. The salt is added to the organic solutions until the crystals stop clumping together.It is also used in frosting windows, in carpet fresheners, the manufacture of starch and as an additive to cattle feed.

CAS No. 7757-82-6
Molecular Formula Na2SO4
Synonyms Disodium sulphate, salt cake
Physical State Crystal or powder
Color White
Odor Odorless
Soluble Water
Specific Gravity (Water = 1) 2.68
Melting Point, °C 888
Boiling point, °C 1700
Sodium sulphate(Na2SO4), % by wt Min. 99.0
Water-indissoluble, % by wt Max. 0.05
Calcium magnesium (count Mg), % by wt Max. 0.15
Chloride(count Cl), % by wt Max. 0.35
(Fe), % by wt Max. 0.002
Water, % by wt Max. 0.20