Studies in the system calcium sulphate–water. Part II. The kinetics of dehydration of β-CaSO4,½H2O

Abstract

The kinetics of dehydration of β-calcium sulphate hemihydrate have been studied isothermally between 115° and 140°, at constant partial pressures of water vapour between 10^–5mm. and 42 mm. The results are consistent with a diffusion-controlled mechanism having an activation energy varying between 6·4 kcal./mole at a partial pressure of water vapour of 10^–5 and 49 kcal./mole at 42 mm.