The Ageing of Sesquioxide Gels II. Alumina Gels

R. C. Mackenzie, R. Meldau and J. A. Gard
The Macaulay Institute for Soil Research, Aberdeen, Scotland
Carl-Bertelsmannstrasse 4, Gütersloh, Germany
Department of Chemistry, University of Aberdeen, Scotland.

Summary: Aluminium oxides occur widely in soils and are of considerable pedological significance. The ageing of alumina gels, prepared from aluminium chloride and ammonia, into crystalline hydroxides has been investigated using thermal, X-ray, infra-red, and electron-microscope techniques. At room temperature ageing is more rapid at high pH values. The structure of the original gel particles appears to resemble boehmite and ageing causes the formation of bayerite with small amounts of gibbsite. The morphology of the various mineral types is considered and a mechanism of ageing suggested.

Mineralogical Magazine; June 1962 v. 33; no. 257; p. 145-157; DOI: 10.1180/minmag.1962.033.257.08
© 1962, The Mineralogical Society
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