Calcium Sulphate Hemihydrate 96%

Calcium sulphate (or calcium sulfate) is a common laboratory and industrial chemical. In the form of gamma-anhydrite (the nearly anhydrous form), it is used as a desiccant. It is also used as a coagulant in products like tofu. In the natural state, unrefined calcium sulphate is a translucent, crystalline white rock. When sold as a colour-indicating variant under the name Drierite, it appears blue or pink due to impregnation with Cobalt(II) chloride, which functions as a moisture indicator. The hemihydrate (CaSO4.~0.5H2O) is better known as plaster of Paris, while the dihydrate (CaSO4.2H2O) occurs naturally as gypsum. The anhydrous form occurs naturally as beta-anhydrite. Depending on the method of calcination of calcium sulphate dihydrate, specific hemihydrates are sometimes distinguished: alpha-hemihydrate and beta-hemihydrate. They appear to differ only in crystal shape. Alpha-hemihydrate crystals are more prismatic than beta-hemihydrate crystals and, when mixed with water, form a much stronger and harder superstructure.

Calcium Sulphate Hemihydrate 96%

• Used as a common component of fouling deposits in industrial heat exchangers

Minimum Assay: <96%
Molecular Weight: 136.14 g/mol
Melting Point: 1450 °C
Plaster to water ratio (by weight): 1.47:1
Water to plaster ratio (by weight): 68%
Plaster to water mix ratio (by weight): 100/68
Chemical composition: CaSO_4.1/2H₂O
Colour: Off white
Vicat ring fluidity (cm): 19
Initial setting time (minutes): 9
Final setting time (minutes): 13
Linear Expansion (%): 0.26
Brinell hardness (MPa): 20
Dry compressive strength (MPa): 16
Wet compressive strength (MPa): 7
Pore volume (%):  44%
Particle size (% weight retained) -
5% at 150 µm
18% at 90 µm
33% at 63 µm
50% at 32 µm
Loose bulk density (kg/m₃): 900
Compacted bulk density (kg/m₃): 1300

Cas Number: 7778-18-9

Einecs Number: 231-900-3

HS Code / Commodity Code: 2520100000

Hazard Phrases: H0001