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Re-examination of the kinetics of the thermal dehydroxylation of kaolinite

Published online by Cambridge University Press:  09 July 2018

J. M. Criado ,
A. Ortega ,
C. Real  and
E. Torres De Torres
J. M. Criado
Affiliation:
Departamento de Quimica Inorganica, Facultad de Quimica de la Universidad de Sevilla y Departamento de Investigaciones Fisicas y Quimicas, Centro Coordinado del CSIC, Sevilla, Spain
A. Ortega
Affiliation:
Departamento de Quimica Inorganica, Facultad de Quimica de la Universidad de Sevilla y Departamento de Investigaciones Fisicas y Quimicas, Centro Coordinado del CSIC, Sevilla, Spain
C. Real
Affiliation:
Departamento de Quimica Inorganica, Facultad de Quimica de la Universidad de Sevilla y Departamento de Investigaciones Fisicas y Quimicas, Centro Coordinado del CSIC, Sevilla, Spain
E. Torres De Torres
Affiliation:
Departamento de Quimica Inorganica, Facultad de Quimica de la Universidad de Sevilla y Departamento de Investigaciones Fisicas y Quimicas, Centro Coordinado del CSIC, Sevilla, Spain
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Abstract

The results obtained from this study of kaolinite dehydroxylation explain why different investigators have ascribed both first-order kinetics and a diffusion mechanism to this reaction. The fact that activation energies reported by these workers agree well, in spite of the different kinetics assumed when performing the calculations, is also explained. From a comparison of the results obtained by isothermal and non-isothermal methods it is concluded that, for reacted fractions, α, <0·6, kaolinite dehydroxylation is controlled by a diffusion process. A reaction mechanism explaining this behaviour is proposed.

Type
Research Article
Information
Clay Minerals , Volume 19 , Issue 4 , September 1984 , pp. 653 - 661
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1984

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