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Estimation of iron oxides in soil clays by profile refinement combined with differential X-ray diffraction

Published online by Cambridge University Press:  09 July 2018

G. Brown  and
I. G. Wood
G. Brown
Affiliation:
Soils and Plant Nutrition Department, Rothamsted Experimental Station, Harpenden, Hertfordshire AL5 2JQ
I. G. Wood
Affiliation:
Soils and Plant Nutrition Department, Rothamsted Experimental Station, Harpenden, Hertfordshire AL5 2JQ
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Abstract

A procedure is described for the quantitative estimation of hematite, goethite and lepidocrocite in soil clays by differential X-ray diffraction combined with profile refinement. The method has been applied to clays from 12 palaeosol horizons from south-east England. Samples containing as little as 1% dithionite-extractable iron can be analysed in this way. The hematite: goethite ratio is determined to within ±3% for soil clays having ∼2.5% of each oxide and to within 10% in less favourable cases. The concentration of oxides in the soil determined solely from X-ray diffraction and from a combined chemical analysis/X-ray method are in good agreement. In addition to improving the accuracy and extending the range of iron-oxide concentrations over which analysis can be carried out, the method may, in principle, be used to provide information about the cell parameters and line profiles of each component present.

Type
Research Article
Information
Clay Minerals , Volume 20 , Issue 1 , March 1985 , pp. 15 - 27
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1985

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