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A Kinetic Study of the Dehydroxylation of Kaolinite

Published online by Cambridge University Press:  01 January 2024

G. W. Brindley  and
M. Nakahira
G. W. Brindley
Affiliation:
Department of Ceramic Technology, The Pennsylvania State University, University Park, Pennsylvania, USA
M. Nakahira
Affiliation:
Department of Ceramic Technology, The Pennsylvania State University, University Park, Pennsylvania, USA
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Abstract

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When dehydroxylation of kaolinite powder is carried out in the usual way, the linear relations anticipated for first-order kinetics and for the Arrhenius plot of log k versus 1/T are satisfied only very approximately. Factors relating to the form of the specimen, (shape, size, compaction, container, etc.) are shown to be very important. A method is developed for obtaining data for a specimen in the form of an infinitely thin disc. The first-order kinetic relation and the Arrhenius relation are then linear, and the latter gives an activation energy of 65 K cal./mol. The dehydroxylation process is shown by x-ray analysis to proceed crystal by crystal and this leads to an interpretation of the first-order kinetics. The x-ray method is used to study the distribution of reacted and unreacted material throughout a disc of material. Although isothermal conditions are employed, large differences are found between the interior and exterior of a partially dehydroxylated disc. These effects are attributed to the influence of a water vapor atmosphere within the heated disc.

Type
Article
Information
Clays and Clay Minerals (National Conference on Clays and Clay Minerals) , Volume 5 , February 1956 , pp. 266 - 278
Copyright
Copyright © Clay Minerals Society 1956

Footnotes

Contribution no. 56-35 from the College of Mineral Industries, The Pennsylvania State University, University Park, Pennsylvania.

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