The transformation of synthetic hectorite in the presence of Cu(II)
Fischer, Hakon (ETH Zurich. Institute of Geophysics)
Weidler, Peter G. (Institute for Technical Chemistry. Water- and Geotechnology. Forschungszentrum Karlsruhe)
Grobéty, Bernard (Université de Fribourg. Institut de Minéralogie)
Luster, Jörg (Swiss Federal Institute for Forest. Snow and Landscape Research)
Gehring, Andreas U. (ETH Zurich. Institute of Geophysics)

Date:	2009
Abstract:	The influence of Cu(II) on the hydrothermal and thermal transformations of a synthetic hectorite was investigated by a combined approach using mainly X-ray diffraction, thermal analyses, and electron paramagnetic resonance spectroscopy. The presence of Cu(II) during hydrothermal treatment increased the crystallite size. Copper (II) was both structure-bound and associated with the inner surfaces of the particles. Upon heating, structural destabilization of the hectorite began at ~400°C as indicated by the formation of free radicals. Between 600 and 700°C, the hectorite converted to enstatite, and in the presence of Cu(II), to enstatite and richterite. The formation of richterite as an additional conversion product is explained by the creation of structural weakness due to structure-bound Cu(II) in F-containing hectorite. Our results suggest that traces of Cu(II), typical of natural environments, may influence the conversion products in high-temperature geochemical systems.
Rights:	Tots els drets reservats.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Cu(II) ; DSC ; EPR ; Hectorite ; Hydrothermal treatment ; TG ; XRD
Published in:	Clays and Clay Minerals, Vol. 57, Núm. 2 (2009) , p. 139-149, ISSN 1552-8367

DOI: 10.1346/CCMN.2009.0570201

11 p, 1.2 MB  UAB restricted access

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