Abstract
The formation of hematite from amorphous Fe(III)hydroxide in aqueous systems at pH 6 and 70°C, both with and without oxalate, was followed by kinetic measurements, electron microscopy, i.r. spectroscopy and thermal analysis.
In the absence of oxalate, small amorphous particles coalesce into aggregates which eventually become single crystals of hematite. When oxalate is present, crystal growth is much faster and does not proceed through the intermediate stage of aggregation. Aggregates, when formed, consist of groups of single crystals. It is suggested that oxalate accelerates the nucleation of hematite crystals by acting as a template, the Fe-Fe distance in Fe-oxalate ions being similar to that in hematite.
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References
Afremow, L. C., and Vandeberg, J. T., (1966) High resolution spectra of inorganic pigments and extenders in the mid-i.r. region from 1500cm-1-200cm-1: J. Paint Techn. 38, 169–201.
Chukhrov, F. V., Zvyagin, B. B., Ermilova, L. P., and Gorsh-kov, A. I., (1972) New data on iron oxides in the weathering zone: Proc. Intern. Clay Conf. Madrid 1, 333–342.
Farmer, V. C., and Mitchell, B. D., (1963) Occurrence of oxalates in soil clays following hydrogen peroxide treatment: Soil Sci. 96, 221–229.
Feitknecht, W. and Michaelis, W. (1962) Über die Hydrolyse von Eisen(III)-perchlorat-Lösungen: Helv. Chim. Acta 45, 212–224.
Fischer, W. R., (1971) Modellversuche zur Bildung und Auflösung von Goethit und amorphen Eisenoxiden im Boden. Diss. T. U. München.
Garavelli, C. (1957) La struttura della oxalite FeC2O4.2H2O. Period. Min: 26, 269–303.
Langmuir, D. (1971) Particle size effect on the reaction goethite = hematite + water: Am. J. Sci. 271, 147–156.
Mackay, A. L., (1960) Some aspects of the topochemistry of the iron oxides and hydroxides: 4th Int. Symp. Reactivity of Solids, Amsterdam 571–583.
Mohr, E. C. J., v. Baren, F. A., and v. Schuylenborgh, J. (1972) Tropical Soils, 3rd Edition, pp. 433–450, Den Haag.
Schmelz, M. J., et al. (1957) I.r. absorption spectra of inorganic coordination complexes, IX. I.r. spectra of oxalato complexes: Spectrochim. Acta 9, 51–58.
Schwertmann, U. (1964) Differenzierung der Eisenoxide des Bodens durch photochemische Extraktion mit saurer Ammoniumoxalat-Lösung: Z. Pflanzenernähr. Düng. Bodenkunde 105, 194–202.
Schwertmann, U. (1969) Die Bildung von Eisenoxidmineralen: Fortschr. Min. 46, 274–285.
Schwertmann, U. (1969/70) Der Einfluß einfacher organischer Anionen auf die Bildung von Goethit und Hämatit aus amorphem Eisen(III)-hydroxid: Geoderma 3, 207–214.
Schwertmann, U., and Fischer, W. R., (1966) Zur Bildung von α-Fe(OH) und α-Fe2O3 aus amorphem Eisen(III)-hy-droxid: Z. anorg. allg. Chem. 346, 137–142.
Schwertmann, U. and Fischer, W. R., (1973) Natural ‘amorphous’ ferric hydroxide: Geoderma 10, 237–247.
Schwertmann, U. and Taylor, R. M., (1972) The transformation of lepidodocrocite to goethite: Clavs and Clay Minerals 20, 151–158.
Towe, K. M., and Bradley, W. F., (1967) Mineralogical constitution of colloidal ‘hydrous ferric oxides’: J. Colloid. Interface Sci. 24, 384–392.
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Fischer, W.R., Schwertmann, U. The Formation of Hematite from Amorphous Iron(III)Hydroxide. Clays Clay Miner. 23, 33–37 (1975). https://doi.org/10.1346/CCMN.1975.0230105
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DOI: https://doi.org/10.1346/CCMN.1975.0230105