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Determination of porosity of platy materials using slit-shaped and bevelled pores

Published online by Cambridge University Press:  09 July 2018

J. F. Delon
Affiliation:
Centre de Recherche sur la Valorisation des Minerais de l'ENSG et UA 235 du CNRS, B.P. 40, 54501 Vandoeuvre Cédex, France
O. Lietard
Affiliation:
Centre de Recherche sur la Valorisation des Minerais de l'ENSG et UA 235 du CNRS, B.P. 40, 54501 Vandoeuvre Cédex, France
J. M. Cases
Affiliation:
Centre de Recherche sur la Valorisation des Minerais de l'ENSG et UA 235 du CNRS, B.P. 40, 54501 Vandoeuvre Cédex, France
J. Yvon
Affiliation:
Centre de Recherche sur la Valorisation des Minerais de l'ENSG et UA 235 du CNRS, B.P. 40, 54501 Vandoeuvre Cédex, France

Abstract

The pore-size distribution of kaolinite has been studied by nitrogen desorption isotherms. A new method is proposed which takes account of the fact that the intraparticle or ‘internal’ area is small in comparison with the total surface area. The crystals form dihedral angles with one another, and the irregularities of the crystal edges form a slit-shaped internal pore system. When the nitrogen pressure increases, the condensed volume in the pores grows by an amount greater than predicted by de Boer's law. This excess is shown to result from capillary condensation in bevelled pores and this accounts for the main part of the intercrystalline or ‘external’ porosity. A model of condensation in bevelled capillaries has been developed and its range of validity determined.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1986

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