The dehydration processes of calcium sulfate dihydrate have been studied isothermally under the partial pressures of water vapor between about 0.2 and 187.5 mmHg.
At the region of the partial pressures of water vapor in the present experiment, the rate-controlled steps of the dehydration of calcium sulfate dihydrate proceed according to the following process as the temperature increases ;
Nucleation control → Phase boundary control → Diffusion control
The activation energies of dehydration of 3/2 H
2O in each rate-cotrolled steps are found that the nucleation control has energies between 30.8 and 43.1, the phase boundary control between 22.0 and 34.1 and the diffusion control between 12.3 and 25.2 kcal/mol.
抄録全体を表示