Study of gypsum by PDSC
Calcium sulfate dihydrate has been widely characterized by both differential scanning calorimetry and thermogravimetry (TG). Two dehydration processes were reported to be partially overlapping. High resolution TG and water vapor self generated atmosphere pin-hole lid strategies were used to increase the resolution of both dehydration processes. In this study, isobaric experiments were carried out in a pressure differential scanning calorimetry cell. The approach consisted in combining the pin-hole lid with different pressures with nitrogen atmosphere. Resolution was improved at moderately low pressures. At higher pressures other processes were observed.
KeywordsGypsum PDSC Pressure Crystallization Vapor Water
This study was partially funded by the Spanish Ministerio de Educacion y Ciencia MTM2008-00166 and MAT2010-21342-C02-01.
- 1.Groves AW. Gypsum and anhydrite. London: Her Majesty’s Stationery Office; 1958. p. 108.Google Scholar
- 2.Taylor HFW. Cement chemistry. London: Academic Press; 1990. p. 233.Google Scholar
- 4.Ramachandran VS. Applications of differential thermal analysis in cement chemistry. New York: Chemical Publishing Co Inc.; 1969. p. 251–270.Google Scholar
- 11.Lehman H, Rieke K. Investigations of the system CaSO4–H2O under special considerations of material and experimental parameters by differential thermal analysis. Proceedings of the 4th international conference on thermal analysis. Budapest; 1975;1:573–83.Google Scholar
- 13.Tydlitát V, Medveď I, Černý R. Determination of a partial phase composition in calcined gypsum by calorimetric analysis of hydration kinetics. J Therm Anal Calorim. 2011. doi: 10.1007/s10973-011-1334-y.
- 15.Comodi P, Kurnosov A, Nazzareni S, Dubrovinsky L. The dehydration process of gypsum under high pressure. Phys Chem Miner. 2012;39:65–71.Google Scholar
- 16.Ramachandran VS. Concrete admixtures handbook. New Delhi: Standard Publishers; 2002.Google Scholar
- 17.Ramachandran VS. Handbook of thermal analysis of construction materials. Norwich: Noyes Publications/William Andrew Pub; 2003.Google Scholar
- 19.Elliot C. Plaster of Paris technology. Chem Trade J. 1923;72:725–6.Google Scholar