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American Mineralogist

Journal of Earth and Planetary Materials

Ed. by Baker, Don / Xu, Hongwu / Swainson, Ian


IMPACT FACTOR 2018: 2.631

CiteScore 2018: 2.55

SCImago Journal Rank (SJR) 2018: 1.355
Source Normalized Impact per Paper (SNIP) 2018: 1.103

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1945-3027
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Volume 98, Issue 10

Issues

Thermodynamic properties of saponite, nontronite, and vermiculite derived from calorimetric measurements

Hélène Gailhanou / Philippe Blanc / Jacques Rogez / Georges Mikaelian / Katsuya Horiuchi
  • Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8571, Japan
  • Other articles by this author:
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/ Yasuhisa Yamamura
  • Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8571, Japan
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/ Kazuya Saito
  • Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8571, Japan
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/ Hitoshi Kawaji / Fabienne Warmont / Jean-Marc Grenèche
  • LUNAM, Université du Maine, Institut des Molécules et Matériaux du Mans, UMR CNRS 6283, F-72085 Le Mans Cedex 9, France
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/ Philippe Vieillard / Claire I. Fialips / Eric Giffaut / Eric C. Gaucher
Published Online: 2015-03-07 | DOI: https://doi.org/10.2138/am.2013.4344

Abstract

The stability of clay minerals is an important factor in assessing the durability of containment barriers for deep waste storage. In that context, the complete thermodynamic data set of three 2:1 ferro-magnesian clay minerals have been determined at 1 bar and from 2 to 520 K, using calorimetric methods. The studied clay samples were, respectively, the Na-saturated saponite Sap-Ca-1, Na0.394 K0.021Ca0.038(Si3.569Al0.397Fe3+0.034)(Mg2.948Fe2+0.021Mn0.001)O10(OH)2, the Ca-saturated nontronite NAu-1, Ca0.247K0.020(Si3.458Al0.542)(Mg0.066Fe3+1.688Al0.268Ti0.007)O10(OH)2, and the Ca-saturated Santa Olalla vermiculite, Ca0.445(Si2.778Al1.222)(Al0.192Mg2.468Fe3+0.226Fe2+0.028Ti0.018Mn0.007)O10(OH)2. The standard enthalpies of formation were obtained by solution-reaction calorimetry at 298.15 K. The heat capacities were measured between 2 and 520 K, using low-temperature adiabatic calorimetry, heat-pulse calorimetry, and differential scanning calorimetry. The standard entropies and the Gibbs free energies of formation at 298.15 K have been calculated from these values. Finally, the equilibrium constants at 298.15 K have been determined.

A comparison between these experimental data and estimated values obtained from prediction models available in the literature enabled the most usual calculation methods available to date to be assessed for each thermodynamic property.

Keywords : Clay mineral; saponite; nontronite; vermiculite; thermodynamic data; enthalpy; Gibbs free energy; entropy; calorimetry; dissolution

About the article

Received: 2012-09-10

Accepted: 2013-06-15

Published Online: 2015-03-07

Published in Print: 2013-10-01


Citation Information: American Mineralogist, Volume 98, Issue 10, Pages 1834–1847, ISSN (Online) 1945-3027, ISSN (Print) 0003-004X, DOI: https://doi.org/10.2138/am.2013.4344.

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© 2015 by Walter de Gruyter Berlin/Boston.

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