Kinetics of the calcination of calcium sulphate dihydrate

The kinetics of calcination of calcium sulphate dihydrate were studied at 100° at air pressures from 760 to less than 10^?5 mm Hg. Any reduction in air pressure below atmospheric caused an increase in reaction rate. Water vapour removal initially facilitated the dehydration at higher pressures, but began to impede the reaction at low pressures.