Abstract
Simultaneous DTA-TG has been carried out on a set of natural vermiculite samples. Based on their dehydration behaviour the samples can be divided in two groups: (a) those with DTA endothermic peak temperatures at 140°–150°C and 240°–270°C (pure vermiculties) and (b) those with peak temperatures at 95°–115°C (vermiculite with mica or mica-vermiculite interstratifications). The low temperature at which the endothermic effect in group (b) appears is discussed on the basis of dilution due to the inert layers of mica, differences in chemical composition, and lowering of interlamellar water bond energy.
Zusammenfassung
An einer Reihe von natürlichen Vermikulitproben wurde simultane DTA-TG durchgeführt. Anhand ihres Dehydrationsverhaltens können diese Proben zwei Gruppen zugeordnet werden: (a) jene mit endothermen DTA-Peaktemperaturen von 140°–150°C und 240°–270°C (reine Vermikulite) und (b) jene mit Peaktemperaturen von 95°–115°C (Vermikulit mit Glimmer oder Glimmer-Vermikulit Zwischenlagerungen.). Die niedrige Temperatur, bei der in Gruppe (b) der endotherme Effekt auftritt, wird anhand der Verdünnung durch inerte Glimmerschichten, den Unterschieden der chemischen Zusammensetzung und der Erniedrigung der interlamellaren Wasserbindungsenergic besprochen.
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Justo, A., Pérez-Rodríguez, J.L. & Sánchez-Soto, P.J. Thermal study of vermiculites and mica-vermiculite interstratifications. Journal of Thermal Analysis 40, 59–65 (1993). https://doi.org/10.1007/BF02546555
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DOI: https://doi.org/10.1007/BF02546555