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On Dehydration of Bound Water of Sepiolite

Published online by Cambridge University Press:  01 July 2024

Hiroshi Nagata ,
Susumu Shimoda  and
Toshio Sudo
Hiroshi Nagata
Affiliation:
Geological and Mineralogical Institute, Faculty of Science, Tokyo University of Education, Tokyo, Japan
Susumu Shimoda
Affiliation:
Geological and Mineralogical Institute, Faculty of Science, Tokyo University of Education, Tokyo, Japan
Toshio Sudo
Affiliation:
Geological and Mineralogical Institute, Faculty of Science, Tokyo University of Education, Tokyo, Japan
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Abstract

Bound water of sepiolite dehydrates in two steps in the temperature range of 250-650°C, as shown in the TG-curve. These steps are described here as steps II and III. At step II, half of the bound water is removed; other half at step III. From step II to III, discontinuous changes are confirmed in such properties as activation energy of dehydration, a-dimension, axial ratio, and intensities and spacings of X-ray powder reflections. A structural state at step II may be recognized as a distinct phase in the dehydration process.

Résumé

Résumé

L’eau liée de la sépiolite part en deux stades dans le domaine de températures de 250-650°C, comme le montrent les courbes d’ATG. Les étapes sont décrites ici comme les stades II et III. Au stade II. la moitié de l’eau liée est éliminée; l’autre moitié est éliminée au stade III. Du stade II au stade III, des changements discontinus sont confirmés dans des propriétés telles que l’énergie d’activation de la déshydratation, la dimension a. le rapport axial, les intensités et les espacements des diagrammes de diffraction X de poudre. Un état structural au stade II peut être reconnu comme une phase distincte au cours du processus de déshydratation.

Kurzreferat

Kurzreferat

Gebundenes Wasser wird von Sepiolit in zwei Stufen im Temperaturbereich von 250-600°C abgegeben, wie an TG-Kurven gezeigt wird. Diese Stufen werden hier als Stufen II und III bezeichnet. Bei Stufe II wird die Hälfte des gebundenen Wassers entfernt, die andere Hälfte bei Stufe III. Zwischen Stufe II und III werden diskontinuierliche Veränderungen in solchen Eigenschaften wie Aktivierungsenergie der Dehydratisierung, a-Dimension, Achsenverhältnis und den Intensitäten und Abständen der Röntgenpulverreflexe festgestellt. Der Strukturzustand bei Stufe II kann als eine bestimmte Phase im Entwäasserungsprozeß angesehen werden.

Резюме

Резюме

Связанная вода сепиолитов дегидратируется по двум этапам в пределах температур от 250 до 650°С, как показано на кривой TG. Эти этапы мы называем ступенями II и III. На II ступени удаляется половина связанной воды, а другая половина на III. От II ступени до III, подтверждаются прерывистые изменения в таких свойствах как: энергия активации дегидратирования, я-размер, отношение осей и интенсивности и расстояние между рентгеновскими отражениями на порошкограммах. Структурное состояние на ступени II можно считать определенной фазой процесса дегидратирования.

Type
Research Article
Information
Clays and Clay Minerals , Volume 22 , Issue 3 , June 1974 , pp. 285 - 291
Copyright
Copyright © Clay Minerals Society 1974

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