Clays and Clay Minerals, Vol. 54, No. 6, 667–677, 2006.
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Authors
Bentabol, Maria
Cruz, Maria Dolores Ruiz
Huertas, Francisco Javier
Linares, Jose
Issue Date
2006-11
Type
Article
Language
en_US
Keywords
Periodicals , Geology , Al-rich Serpentine , FTIR , Hydrothermal Synthesis , Mg-rich Kaolinite , TEM/AEM , XRD
Alternative Title
Hydrothermal Synthesis of MG-Rich And Mg-NI-Rich Kaolinite
Abstract
Mg-rich kaolinite and Mg+Ni-rich kaolinite have been synthesized in hydrothermal experiments (200 and 400ºC) from poorly crystalline kaolinite and Mg- and Mg+Ni-bearing solutions. Al-rich serpentine and Al-rich chlorite were obtained as sub-products of the reactions. The formation of these phases occurred through a dissolution-precipitation mechanism that led to spherical kaolinite after short reaction times. A morphological evolution towards platy particles and stacks occurred at increasing run times. Identification of the several phases was carried out using a combination of X-ray diffraction and transmission/analytical electron microscopy. Analytical data indicate that the Mg content in kaolinite increased as a function of the reaction time and temperature, reaching up to 0.46 atoms per half formula unit (a.p.h.f.u.). The measured (Mg+Ni) content reached up to 0.56 a.p.h.f.u.. Both the gradual increase of the b-cell parameter of kaolinite at increasing Mg contents and the presence of new bands on the FTIR spectra of the synthesized kaolinite point to a Mg-for-Al replacement in the octahedral sheet rather than to the presence of serpentine-like layers interstratified in the kaolinite structure.
Description
Citation
Clays and Clay Minerals, Vol. 54, No. 6, 667–677, 2006.
Publisher
The Clay Minerals Society
License
Copyright © 2006-2018.