Hélène Gailhanou
Centre national de la recherche scientifique
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Featured researches published by Hélène Gailhanou.
American Journal of Science | 2015
Philippe Blanc; Philippe Vieillard; Hélène Gailhanou; Stéphane Gaboreau; Eric C. Gaucher; Claire I. Fialips; Benoît Madé; Eric Giffaut
A set of models for estimating the enthalpy of formation, the entropy, the heat capacity and the volume of dehydrated phyllosilicates is presented. The model for entropy and heat capacity estimation is essentially based on a method of decomposition into polyhedral units, similar to that published by Holland (1989). The model for predicting the enthalpy of formation is based on the electronegativity scale, as previously developed by Vieillard (1994a, 1994b). For the sake of consistency, the models are parameterized using the same critical selection of thermodynamic properties from the literature. This includes a set of direct measurements especially dedicated to clay minerals that had not been taken into account in previous calculation methods. The accuracy of the predictions is tested for each property. The verification tests are also carried out for minerals that include different chemical elements than the phases used to derive the model constants, especially lithium-bearing micas. Verification tests also concern the Gibbs energy function that combines contributions from both models. Finally, the models are used in order to propose a complete thermodynamic database for clay mineral end-members. The consistency of the stability domains calculated on the basis of these thermodynamic properties is investigated by drawing relevant predominance diagrams for some chemical systems of interest. The models proposed represent a significant improvement with respect to previous works as regards the global accuracy of the estimates and because the developments were realized and tested using the same set of minerals, whose properties had been collected through a critical selection of the literature.
American Mineralogist | 2013
Hélène Gailhanou; Philippe Blanc; Jacques Rogez; G. Mikaelian; Katsuya Horiuchi; Yasuhisa Yamamura; Kazuya Saito; Hitoshi Kawaji; Fabienne Warmont; Jean-Marc Greneche; Philippe Vieillard; Claire I. Fialips; Eric Giffaut; Eric C. Gaucher
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.
Applied Geochemistry | 2014
Eric Giffaut; Mireia Grivé; Philippe Blanc; Philippe Vieillard; Elisenda Colàs; Hélène Gailhanou; Stéphane Gaboreau; Nicolas C.M. Marty; Benoît Madé; Lara Duro
Geotextiles and Geomembranes | 2009
Dominique Guyonnet; Nathalie Touze-Foltz; Véronique Norotte; Catherine Pothier; Gérard Didier; Hélène Gailhanou; Philippe Blanc; Fabienne Warmont
Soil Science Society of America Journal | 2009
Christophe Tournassat; Hélène Gailhanou; Catherine Crouzet; Gilles Braibant; Anne Gautier; Eric C. Gaucher
Geochimica et Cosmochimica Acta | 2007
Hélène Gailhanou; J.C. van Miltenburg; J. Rogez; Juan Olives; Marc Amouric; Eric C. Gaucher; Philippe Blanc
Geochimica et Cosmochimica Acta | 2012
Hélène Gailhanou; Philippe Blanc; Jacques Rogez; G. Mikaelian; Hitoshi Kawaji; Juan Olives; Marc Amouric; Renaud Denoyel; S. Bourrelly; Valérie Montouillout; Philippe Vieillard; Claire I. Fialips; Nicolas Michau; Eric C. Gaucher
Geochimica et Cosmochimica Acta | 2007
Christophe Tournassat; Hélène Gailhanou; Catherine Crouzet; Gilles Braibant; Anne Gautier; Arnault Lassin; Philippe Blanc; Eric C. Gaucher
Geochimica et Cosmochimica Acta | 2009
Hélène Gailhanou; J. Rogez; J.C. van Miltenburg; A.C.G. van Genderen; Jean Marc Greneche; C. Gilles; D. Jalabert; Nicolas Michau; Eric C. Gaucher; Philippe Blanc
Geochimica et Cosmochimica Acta | 2011
Philippe Vieillard; Philippe Blanc; Claire I. Fialips; Hélène Gailhanou; Stéphane Gaboreau