Formation of Quartz-Type Phases During High-Temperature Reactions of Montmorillonites
Yasuaki Uno, Norihiko Kohyama, Mitsuo Sato, Hideo Takeshi, 1985. "Formation of Quartz-Type Phases During High-Temperature Reactions of Montmorillonites", Proceedings of the International Clay Conference Denver, 1985, Leonard G. Schultz, H. van Olphen, Frederick A. Mumpton
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The phase transformations of homoionic montmorillonites and the compositions of high-temperature products have been studied by X-ray powder diffraction and electron microscopy. Quartz-type phases crystallized as high-quartz-like phases that were metastable because of their conversion into other compounds, such as cristobalite, spinel, and cordierite, on prolonged heating. Using the analytical electron microscope, the composition of high-quartz-type phases was found not to be pure Si02, but instead showed a structural formula close to MgAl2Si5014. Cristobalite-type phases were also noted and contained Mg and Al, although the amount was less than in the high-quartz-type phases. The mode of formation and decomposition of high-temperature products was affected by bulk chemical compositions, especially the Mg/Al ratio of the original montmorillonites.
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Proceedings of the International Clay Conference Denver, 1985
The papers included in this proceedings volume are representative of the research on clays being conducted in all parts of the world at the time of publication. Many of the subjects treated are controversial, and although some ideas expressed may not necessarily represent the views of the editors, the referees, or the publisher, they deserve to be brought to the attention of the international clay community.