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Effect of Impurities on Kaolinite Transformations as Examined by High-Temperature X-Ray Diffraction

Published online by Cambridge University Press:  06 March 2019

F.M. Wahl*
Affiliation:
University of Illinois, Urbana, Illinois
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Abstract

The high-temperature continuous X-ray diffraction technique has been used at the University of Illinois for several years in our investigation of structural transformations and the development of phase minerals as natural materials are heated. Of particular interest are the effects which chemical impurities have on predicted structural transformations at elevated temperatures.

The formation of mullite and beta-cristobalite as they develop from the clay mineral kaolinite is examined by continuous X-ray diffraction up to 1450°C, and the influence of added impurities either to enhance or to retard nucleation of these phase minerals is shown. The 2θ range containing diagnostic peaks of both the initial material and of the transition and phase minerals which develop on heating was continually traversed, thus providing a constant record for comparing structural changes vs. temperature.

The furnace used is described in detail, and the effects of added impurities on kaolinite transformations are evaluated to show their importance in controlling the thermal history of a natural material under nonequilibrium conditions.

Type
Research Article
Copyright
Copyright © International Centre for Diffraction Data 1961

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