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Structural and Textural Modifications of Palygorskite and Sepiolite Under Acid Treatment

Published online by Cambridge University Press:  28 February 2024

M. Myriam ,
M. Suárez  and
J. M. Martín-Pozas
M. Myriam
Affiliation:
Area de Cristalografía y Mineralogía, Departamento de Geología, Universidad de Salamanca, Plaza de la Merced s/n, Salamanca, 37008, Spain
M. Suárez
Affiliation:
Area de Cristalografía y Mineralogía, Departamento de Geología, Universidad de Salamanca, Plaza de la Merced s/n, Salamanca, 37008, Spain
J. M. Martín-Pozas
Affiliation:
Area de Cristalografía y Mineralogía, Departamento de Geología, Universidad de Salamanca, Plaza de la Merced s/n, Salamanca, 37008, Spain
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Abstract

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Sepiolite from Mara (Zaragoza, Spain) and palygorskite from Attapulgus (Georgia, USA) were activated by treatment at different concentrations with solutions of boiling HCl under reflux conditions. The natural and treated solids were characterized by mineralogical, chemical and textural analyses.

Acid attack resulted in a progressive dissolution of the octahedral layer of these silicates. Silica contents increased and octahedral cations (Al, Mg and Fe) decreased with the intensity of the acid attack. In both cases, fibrous free silica was obtained.

The sepiolite was destroyed more rapidly than palygorskite under the conditions used because of its magnesic composition and the larger size of its structural microchannels. The maximum increase in specific surface area was obtained for sepiolite at 3 N and for palygorskite at 9 N. Cleaning and disaggregation of the particles and the increase in the number of micropores were responsible for this increase in specific surface area.

Keywords

Acid AttackActivation of ClaysFibrous SilicaPalygorskiteSepiolite
Type
Research Article
Information
Clays and Clay Minerals , Volume 46 , Issue 3 , June 1998 , pp. 225 - 231
Copyright
Copyright © 1998, The Clay Minerals Society

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