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Quantitative determination of goethite and hematite in kaolinitic soils by X-ray diffraction

Published online by Cambridge University Press:  09 July 2018

N. Kämpf  and
N. Schwertmann
N. Kämpf
Affiliation:
Institut für Bodenkunde, Technische Universität München, 8050 Freising-Weihenstephan, FRG
N. Schwertmann
Affiliation:
Institut für Bodenkunde, Technische Universität München, 8050 Freising-Weihenstephan, FRG
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Extract

In the past, two factors have impeded the quantitative estimate of Fe-oxides in soils by X-ray diffraction. First, Fe-oxides are still quite often considered X-ray amorphous, although numerous results, e.g. a low ratio of oxalate- to dithionite-soluble Fe, have indicated the opposite. Second, even if crystalline, the cocentration of Fe-oxides in many soils is low, thereby complicating their identification by XRD. Recently, however, more sensitive methods such as Mössbauer spectroscopy and Differential-XRD (Schulze, 1981) have been introduced, which substantially reduce the lower limit of detection. Because these two methods are not generally available and, especially in the case of M&oum;ssbauer spectroscopy, are rather time consuming, ordinary XRD should be adapted for quantitative estimation of Fe-oxides.

Determination can be facilitated by using samples in which the Fe-oxides are concentrated by particle-size separation and a 5 M NaOH boiling treatment (Norrish & Taylor, 1961). The latter treatment is particularly suitable for kaolinitic soils as the Fe-oxides are unaffected―provided certain precautions are taken (Käimpf & Schwertmann, 1982a). This paper gives details of a procedure for the quantitative estimation of goethite (Gt) and hematite (Hm) by XRD.

Type
Notes
Information
Clay Minerals , Volume 17 , Issue 3 , September 1982 , pp. 359 - 363
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1982

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References

Kämpf, N. (1981) Die Eisenoxidmineralogie einer Klimasequenz von Böden aus Eruptiva in Rio Grande do Sul, Brasilien. Dissertation Techn. Univ. München.Google Scholar
Kämpf, N. & Schwertmann, U. (1982a) The 5 M NaOH concentration method for iron oxides in soils. Clays Clay Min. (in press).CrossRefGoogle Scholar
Kämpf, N. & Schwertmann, U. (1982b) Goethite and hematite in a soil climosequence from volcanic rocks in southern Brazil and its usefulness for differentiating kaolinitic soils. Geoderma, (in press).Google Scholar
Klug, H.P. & Alexander, L.E. (1974) X-ray diffraction procedures. Wiley, New York.Google Scholar
Mehra, O.P. & Jackson, M.L. (1960) Iron oxide removal from soils and clays by a dithionite-citrate system buffered with sodium bicarbonate. Clays Clay Miner. 7, 317–327.Google Scholar
Norrisk, K. & Taylor, R.M. (1961) The isomorphous replacement of iron by aluminium in soil goethites. J. Soil Sci. 12, 294–306.CrossRefGoogle Scholar
Schulze, D.G. (1981) Identification of soil iron oxide minerals by differential X-ray diffraction. Soil Sci. Soc. Am. J. 45, 437–440.Google Scholar
Schwertmann, U. & Fitzpatrick, R.W. (1977) Occurrence of lepidocrocite and its association with goethite in Natal soils. Soil Sci. Soc. Am. J. 41, 1013–1018.CrossRefGoogle Scholar
Steinwehr, H.E.V. (1967) Gitterkonstanten im System α-(Al,Fe,Cr)2O3 und ihr Abweichen von der Vegardregel. Z. Kristallogr. Mineral. 125, 377–403.Google Scholar
Thiel, R. (1963) Zum System α-FeOOH-α-AlOOH. Z. anorg. allg. Chem. 326, 70–78.Google Scholar
Torrent, J., Schwertmann, U. & Schulze, D.G. (1980) Iron oxide mineralogy of some soils of two river terrace sequences in Spain. Geoderma 23, 191–208.CrossRefGoogle Scholar