Characterization of the expandable clays formed from kaolinite at 200°C

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doi: 10.1180/0009855033840108
Authors:Ventabol, M.; Ruiz, M. D.; Huertas, F. J.; Linares, J.
Author Affiliations:Primary:
Universidad de Mélaga, Departamento de Química Inorgánica, Cristalografia y Mineralogía, Malaga, Spain
Volume Title:Clay Minerals
Source:Clay Minerals, 38(4), p.445-458. Publisher: Mineralogical Society, London, United Kingdom. ISSN: 0009-8558
Publication Date:2003
Note:In English. 26 refs.; illus., incl. 5 tables
Summary:The hydrothermal reaction of kaolinite in the system Na2O - K2O - MgO - Al2O3 - SiO2 - H2O - HCl, at near-neutral pH conditions, has been investigated at 200°C, for times from 12 h to 180 days. X-ray diffraction (XRD) study of the solid products indicates that the phases formed from 15 days' reaction time are randomly ordered mixed-layer chlorite-smectite, dioctahedral on average, with a chlorite:smectite ratio of ∼1:2. No structural evolution was observed with increasing reaction time. Investigation by transmission electron microscopy revealed, on the contrary, that very thin packets with basal spacing of either 10 Å (smectite) or 14 Å (chlorite) are dominant. In addition, packets with periodicities of 12-13 Å are also observed. Only rarely, randomly to ordered sequences of 10 and 14 Å are observed in the packets. These observations indicate that the mixture of these phases behaves in XRD as randomly ordered mixed-layer chlorite-smectite. Chemical analysis of the solutions suggests that the neo-formed phases are metastable and would evolve, at longer reaction times, toward ordered mixed-layer chlorite-smectite or to clinochlore. [G.C.]
Sections:Clay minerals; Experimental mineralogy
Subsections:Specific structures: silicates; Techniques; structure; properties
Mineral Groups:Sheet silicates
Subjects:Chemical properties; Clay mineralogy; Clay minerals; Expansive materials; Experimental studies; Geochemistry; Hydrothermal conditions; Kaolinite; Mixed-layer minerals; Sheet silicates; Silicates; Smectite; Vermiculite
Abstract Numbers:04M/3983
Record ID:2004083652
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute.
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