Calcium Sulfate Dihydrate → Calcium Sulfate, Hemihydrate

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Reaction Steps

When calcium sulfate dihydrate is heated sufficiently, a process called calcining, the water of hydration is driven off and there can be formed either calcium sulfate hemihydrate (CaSC4 ·1/2H2O ) or calcium sulfate anhydrite (CaSO4), depending on the temperature and duration of exposure. The term "calcined gypsum," as used herein, refers to both the hemihydrate and anhydrite forms of calcium sulfate.

Provenance & Evidence