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The influence of aluminium on iron oxides: IX. Dissolution of Al-goethites in 6 M HCl

Published online by Cambridge University Press:  09 July 2018

U. Schwertmann
U. Schwertmann*
Affiliation:
Institut für Bodenkunde, Technische Universität München, 8050 Freising-Weihenstephan, FRG
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Abstract

The rate of dissolution of synthetic Al-goethites with 0–10 mole% Al in 6 m HCl at 24°C decreases markedly with increasing extent of Al substitution. Most of the dissolution-time curves are S-shaped, suggesting some increase in surface area during the initial stages of dissolution. Based on electron microscopic examination, the increase in surface area is explained by preferential dissolution of less ordered ‘interdomainic’ zones and the consequent production of isolated ‘domains’. Thin sections of crystals provided some support for defect zones oriented parallel to the crystallographic c-direction. Stepwise multiple correlation analysis employing various properties of the goethites was used to investigate the large variation in half-dissolution time (1–96 h). 94% of the variation could be explained by the variation of the mean crystallite dimension perpendicular to the planes (110) and (111) (MCD110, MCD111). Inclusion of Al-substitution increased R2 to only 97%. As shown in a separate experiment, increasing Al concentration in the system retarded crystal growth. It is therefore believed that Al affects the dissolution rate of goethites not directly, but indirectly, by influencing crystal growth rate which, in turn, affects crystal size and order as measured by MCD110 and MCD111.

Type
Research Article
Information
Clay Minerals , Volume 19 , Issue 1 , February 1984 , pp. 9 - 19
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1984

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References

Cornell, R.M., Posner, A.M. & Quirk, J.P. (1974) Crystal morphology and the dissolution of goethite. J. inorg. nucl. Chem. 36, 1937–1946.Google Scholar
Cornell, R.M., Posner, A.M. & Quirk, J.P. (1975) The complete dissolution of goethite. J. appl. Chem. Biotechnol. 25, 701–706.Google Scholar
Correns, C.W. & von Engelhardt, W. (1953) Röntgenographische Untersuchungen über den Mineralbestand sedimentärer Eisenseze. Nachr. Akad. Wiss Göttingen. Math.-Phys. Kl, 213 131–137.Google Scholar
Fitzpatrick, R.W. & Schwertmann, U. (1982) Al-substituted goethite—an indicator of pedogenic and other weathering environments in South Africa. Geoderma 27, 335–347.CrossRefGoogle Scholar
Golden, D.C. (1978) Physical and chemical properties of aluminium-substituted goethite. PhD. thesis, Univ. of North Carolina, U.S.A.Google Scholar
Jayman, T.C.Z. & Sivasubramaniam, S. (1974) The use of ascorbic acid to eliminate interference from iron in the aluminon method for determining aluminium in plant soil extracts. Analyst 99, 296–301.Google Scholar
Jonas, K. & Solymar, K. (1970) Preparation, X-ray, derivatographic and infrared study of aluminiumsubstituted goethites. Acta Chim. Acad. Sci. Hung. 66, 383–394.Google Scholar
Koutler-Anderson, E. (1953) The sulfosalicylic acid method for iron determinations and its use in certain soil analyses. Ann. Roy. Agric. Coll. Sweden 20, 297–299.Google Scholar
Norrish, K. & Taylor, R.M. (1961) The isomorphous replacement of iron by aluminium in soil goethites. J. Soil Sci. 12, 294–306.Google Scholar
Schulze, D.G. (1984) The influence of aluminum on iron oxides. VIII. Unit-cell dimensions of Al-substituted goethites and estimation of Al from them. Clays Clay Miner. 32 (in press).CrossRefGoogle Scholar
Schulze, D.G. & Schwertmann, U. (1984) The influence of aluminum on iron oxides. X. Properties of Al-substituted goethites. Clays Clay Miner. 32 (in press).CrossRefGoogle Scholar
Schwarzmann, E. & Sparr, H. (1969) Die Wasserstoffbrückenbindung in Hydroxiden mit Diasporstruktur. Z. Naturforsch. 24b, 8–11.Google Scholar
Sidhu, P.S., Gilkes, R.J. & Posner, A. (1981) Oxidation and ejection of nickel and zinc from natural and synthetic magnetites. Soil Sci. Soc. Am. J. 45, 641–644.Google Scholar
Thiel, R. (1963) Zum System α-FeOOH-α-AlOOH. Z. anorg. allg. Chem. 326, 70–78.Google Scholar