Product Name: Calcium sulfate dihydrate
Synonyms: GYPSUM;c.i. 77231;CALCIUM SULFATE-2-HYDRATE;CALCIUM SULFATE SOLUTION R;CALCIUM SULFATE DIHYDRATE;CALCIUM SULPHATE 2H2O;CALCIUM SULPHATE 2-HYDRATE;CALCIUM SULPHATE DIHYDRATE
CAS: 10101-41-4
MF: CaH4O6S
MW: 172.17
EINECS: 231-900-3
Calcium sulfate dehydrate is also known as "natural anhydrite". Chemical formula is CaSO4. The molecular weight is 136.14. It is rhombic system crystal. The relative density is 2.960, refractive index is 1.569,1.575,1.613. Another is soluble anhydrite: melting point is 1450℃, the relative density is 2.89, refractive index is 1.505,1.548, When be incandescent, it can decompose. Its hemihydrate is commonly known as "plaster of Paris", "plaster", it is white amorphous powder, relative density is 2.75. Its dehydrate is commonly known as "gypsum", as a white crystal or powder, relative density is 2.32, refractive index is 1.521,1.523,1.530, when be heated to 163℃, it can lose all crystal water. It is slightly soluble in water, hydrochloric acid, nitric acid, it is soluble in hot sulfuric acid, it is insoluble in alcohol. Natural product is soluble in alkaline sulphates, sodium thiosulfate, aqueous solution of ammonium salt. Method: natural anhydrite is derived by the reaction of CaO with SO3 under red-hot. Soluble anhydrous gypsum is derived by CaSO4·2H2O which heated at 200℃ to constant. Hemihydrate gypsum is derived by the calcination dehydration. Dihydrate is reacted by calcium chloride and ammonium sulfate. The main purpose of calcium sulphate: natural anhydrite is used for medicine; soluble anhydrite can be used for interior decoration, it can also be used to prepare chemicals, beverages, etc; hemihydrate is used for construction materials, but also can be used in plaster statues, ceramics material; its dihydrate is used to product hemihydrate, fillers, etc.