Clays and Clay Minerals, Vol. 55, No. 6, 572–582, 2007.
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Authors
Bentabol, Maria
Cruz, Maria Dolores Ruiz
Huertas, F. Javier
Issue Date
2007
Type
Article
Language
Keywords
Periodicals , Geology , Al-Ni-serpentine , FTIR , Hydrothermal Synthesis , Ni-kaolinite , TEM/AEM , XRD
Alternative Title
Synthesis Of Ni-rich 1:1 Phyllosilicates
Abstract
Rapid dissolution of partly amorphized kaolinite in the systems kaolinite + NiCl2, kaolinite + Ni(OH)2, and kaolinite + NiCl2 + Ni(OH)2, at a temperature of 200ºC and at pH between 5.3 and 7.4, leads to the precipitation of Ni-poor kaolinite, Ni-rich kaolinite and Al-Ni-serpentine. Identification of the phases was carried out using a combination of X-ray diffraction and transmission/analytical electron microscopy. Ni-bearing kaolinite shows variable morphologies in the systems studied: stacks of kaolinite with relatively small Ni contents and fine-grained curved particles of Ni-rich kaolinite dominate in the Cl-bearing system; spherical particles with a disordered structure and relatively uniform Ni contents (in the order of 0.15 atoms per formula unit (a.p.f.u.)) and platy particles of Al-Ni-serpentine characterize the products formed in the Ni(OH)2-richest systems. The presence of Ni(OH)2 in the systems (with and without Cl) favors the dissolution process as well as rapid precipitation of spherical particles, and the formation of serpentine. A difference from Mg systems studied previously is a well defined phase intermediate in composition between kaolinite and serpentine which originated in the Ni-bearing systems. Increasing Ni content is clearly reflected in the parallel increase in the b cell parameter of kaolinite. The average composition of the coexisting Al-Ni-serpentine is: (Al1.24Ti0.01Fe0.02Ni1.31) (Si1.58Al0.42)O5(OH,Cl)2.
Description
Clays and Clay Minerals, Vol. 55, No. 6, 572–582, 2007. Synthesis Of Ni-rich 1:1 Phyllosilicates. Maria Bentabol; Maria Dolores Ruiz Cruz; F. Javier Huertas. DOI: 10.1346/CCMN.2007.0550604. Copyright © 2007, The Clay Minerals Society
Citation
Clays and Clay Minerals, Vol. 55, No. 6, 572–582, 2007.
Publisher
The Clay Minerals Society
License
Copyright © 2006-2018, The Clay Minerals Society