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The thermal decomposition of chrysotile

Published online by Cambridge University Press:  05 July 2018

C. J. Martin
C. J. Martin*
Affiliation:
The Open University, Oxford Research Unit, Foxcombe Hall, Boars' Hill, Oxford1
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Summary

The decomposition of chrysotile fibres heated in air has been studied in the range 100–1400°C by electron microscopy and infra-red absorption. The first observable change in the structure occurred at 580°C, where cavities started to open up between the (001) layers of chrysotile as the fibres were dehydrated, giving rise to strong low-angle diffraction. There was no evidence of any structure in the remaining material but some degree of the original atomic arrangement was preserved for the magnesium silicates, forsterite, and enstatite, later developed in certain preferred orientations. The manner of this crystallization was determined by the thermal treatment, for in samples held between 600°C and 800°C forsterite developed slowly with little further disruption of the fibre while above 800°C the remaining amorphous areas rapidly recrystallized to a mixture of forsterite and enstatite. It is suggested that the mechanisms described by other investigators to explain the development of forsterite in preferred orientations may serve simply to nucleate the crystallization and a similar mechanism to account for the nucleation of the enstatite crystallization is considered. At high temperatures a possible doubling of some of the lattice parameters of the silicates was observed.

Type
Research Article
Information
Mineralogical Magazine , Volume 41 , Issue 320 , December 1977 , pp. 453 - 459
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1977

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Footnotes

1

Present address: Department of Medical Physics, University of Aberdeen, AB9 2ZD.

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