Abstract
The kinetics of gypsum dehydration in non-isothermal conditions with constant heating rate as well in quasi-isotherm, quasi-isobar regime, was investigated. The latter ones of these methods allowed putting in evidence the autocatalytic character of the dehydration, as well as the change of the activation energy with the conversion.
The activation energy change was explained by the crystal growth and sample compaction observed by optical microscopy.
Microscopic observations show that at higher conversions a compaction occur. This process is probably favoured by the accumulation of the water vapour from the dehydration (autogenerate atmosphere). These are the reason for step III characterised by higher activation.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
L. Erdey, F. Paulik and J. Paulik, Hungarian Patent No. 152197, 1962.
F. Paulik, 'Special trends in thermal analysis' John Wiley & Sons, Chichester, New York 1995, p. 177.
J. Rouquerol, Thermochim. Acta, 144 (1980) 31.
E. Segal and D. Fatu, 'Introduction to Non-isothermal Kinetics', Ed. Academiei Romane, Bucharest 1983, p. 64.
M. Avrami, J. Chem. Phys., 7 (1939) 1103; 8 (1940) 212.
B. V. Erofeev, Dokl. Akad. Nauk, SSSR, 52 (1946) 511.
A. W. Coats and P. J. Redfern, Nature, 21 (1964) 68.
J. H. Flynn and L. A. Wall, Polym. Lett., 4 (1966) 323.
E. Urbanovici and E. Segal, Thermochim. Acta, 80 (1984) 379.
D. Fatu and E. Segal, Thermochim. Acta, 61 (1983) 215.
D. Fatu and N. Dragoe, The 11th International Congress on Thermal Analysis and Calorimetry, Philadelphia, USA 1996, Program Book, p. 218.
N. Dragoe, D. Fatu and E. Segal, J. Therm. Anal. Cal., 56 (1999) 793.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Fatu, D. Kinetics of Gypsum Dehydration. Journal of Thermal Analysis and Calorimetry 65, 213–220 (2001). https://doi.org/10.1023/A:1011597106589
Issue Date:
DOI: https://doi.org/10.1023/A:1011597106589