Thermal study of unaltered and altered dolomitic rock samples from ancient monuments
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In this study, the decomposition behaviour of unaltered and altered dolomitic rock samples used in Cultural Heritage buildings was studied by simultaneous TG–DTA experiments at different atmospheres, X-ray diffraction in a high-temperature chamber, and evolved gas analysis. The components of dolomite rock samples and hydrated calcium oxalate formed during the alteration processes of the rocks were characterized, and the decomposition mechanisms of these components were determined. The TG–DTA experiments carried out at CO2 atmosphere were used to determine the carbonate compounds in the rock samples. The TG–DTA study characterized the presence of organic compounds formed during the biological degradation of the rock samples, possibly responsible of the hydrated calcium oxalate formation.
KeywordsCultural Heritage Oxalates Dolomite Calcite Alteration
The authors gratefully acknowledge Prof. M. D. Robador (University of Seville) for providing the samples. A.D. is indebted to the CSIC (MICINN) of Spain for the “Junta de Ampliacion de Estudios” contract (JAE Doc 088). We thank M. C. Jimenez de Haro for her help in SEM measurements. Financial support from projects TEP-03002 from Junta de Andalucía and MAT 2008-06619/MAT from the Spanish Ministerio de Ciencia e Innovación is acknowledged.
- 1.Maniatis Y, Herz N, Basiakos Y, editors. The study of marble and other stones used in antiquity. Los Angeles: J.G. Publications; 1995.Google Scholar
- 13.Avila I, Crnkovic PM, Milioli FE. Thermogravimetric study of the effect of temperature and atmosphere on sulfur dioxide absorption by limestone. Quim Nova. 2006;29:1244–9.Google Scholar
- 15.Webb TL, Krüger JE. Carbonates. In: Mackenzie RC, editor. Differential thermal analysis, vol. 1. New York: Academic Press; 1970.Google Scholar
- 20.Bradley WF, Burst JF, Graf DL. Crystal chemistry and differential thermal effects of dolomite. Am Miner. 1953;38:207–17.Google Scholar
- 31.Carrasco F. Kinetic-study of the thermal decomposition of monohydrate calcium oxalate by thermogravimetric analysis. Afinidad. 1991;48:19–24.Google Scholar
- 44.Beck CW. Differential thermal analysis curves of carbonate minerals. Am Mineral. 1950;35:985–1013.Google Scholar