What is Calcium Sulphate?

Calcium Sulphate: Poorly Soluble Powder

Calcium sulphate is a naturally occurring compound from the minerals anhydrite and gypsum.

Anhydrite can be found in several locations. Gypsum, which slowly dissolves in water, is commonly found in sedimentary rocks.

Angelite is a trade name for blue anhydrite from Peru. 

Calcium sulphate occurs naturally in two forms: a hydrated form, which contains water, and an anhydrous form, which does not. The anhydrous form is known as anhydrite, while the hydrated form is gypsum.

When gypsum is mixed with water and allowed to dry, it hardens to form a solid structure that resists cracking. Because of this property, calcium sulphate is widely used in construction and manufacturing.

Calcium sulphate can occur as a white, odourless powder or as crystals, which can sometimes be tinged with colour due to impurities.

This poorly soluble compound is used extensively in industry, including:

• The production of plaster of Paris

• As a food additive

• In dentistry, particularly for moulds and casts 

• In the building trade for plaster and cement

• In agriculture as a soil improver

• In pharmaceuticals as a calcium supplement

• To increase brightness and whiteness in paper products