What is dihydrate gypsum, what is hemihydrate gypsum, and what is the difference between them?
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In phosphate production, what is dihydrate gypsum, what is hemihydrate gypsum, and what is the difference between them?
Gypsum dihydrate (CaSO4·2H2O), also known as raw gypsum, can be converted into beta-hydrate gypsum (CaSO4·1/2H2O) through calcination and grinding; this latter form is what is used in construction, and is also referred to as plaster or calcined gypsum. Model gypsum can be obtained at a calcination temperature of 190 °C, and its fineness and whiteness are both higher than those of building gypsum. If gypsum is calcined at 400–500 °C or above 800 °C, floor plaster is obtained