Calcium sulfate dihydrate CAS 10101-41-4

Calcium sulfate is also known as "natural anhydrous gypsum". Chemical formula CaSO4. Molecular weight 136.14. Rhombohedral crystal. Relative density of 2.960, refractive indices of 1.569, 1.575, and 1.613. Another type of soluble anhydrous gypsum: melting point 1450 ℃, relative density 2.89, refractive indices 1.505 and 1.548, decomposes at white heat. Its hemihydrate, commonly known as "burnt gypsum" or "matured gypsum", mostly exists in the form of white amorphous powder with a relative density of 2.75. Dihydrate, commonly known as "gypsum", is a white crystal or powder with a relative density of 2.32 and refractive indices of 1.521, 1.523, and 1.530. It loses all crystalline water when heated to 163 ℃. Chemicalbook is slightly soluble in water, hydrochloric acid, and nitric acid, soluble in hot sulfuric acid, and insoluble in alcohol. Natural substances dissolve in alkaline sulfate, sodium thiosulfate, and ammonium salt aqueous solutions. Method: Natural anhydrous gypsum is obtained by reacting CaO and SO3 under red heat. Soluble anhydrous gypsum is obtained by heating CaSO4 · 2H2O to a constant amount at 200 ℃. Half hydrate is obtained by calcining and dehydrating gypsum. Dihydrate is obtained by reacting calcium chloride with ammonium sulfate. The main uses of calcium sulfate: natural anhydrous gypsum is mostly used in medicine; Soluble anhydrous gypsum can be used as indoor decoration, as well as for the production of chemicals, beverages, etc; Hemihydrates are commonly used in building materials and can also be used as gypsum sculptures and ceramic materials; Dihydrate is used to produce hemihydrates, fillers, etc.