Hostname: page-component-78c5997874-ndw9j Total loading time: 0 Render date: 2024-11-15T11:15:47.286Z Has data issue: false hasContentIssue false
  • English
  • Français

Oxidation and Reduction of Structural Iron in Chlorite at 480°C

Published online by Cambridge University Press:  02 April 2024

Ole K. Borggaard ,
Holger B. Lindgreen  and
Steen Mørup
Ole K. Borggaard
Affiliation:
Chemistry Department, Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK-1871, Copenhagen V, Denmark
Holger B. Lindgreen
Affiliation:
Geochemistry Department, Danish Geological Survey, Thoravej 31, DK-2400 Copenhagen NV, Denmark
Steen Mørup
Affiliation:
Laboratory of Applied Physics II, Technical University of Denmark, DK-2800 Lyngby, Denmark
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

An iron-rich chlorite, ripidolite, was oxidized by air-heating at 480°C, i.e., below the dehydroxylation temperature and subsequently reduced in hydrogen at the same temperature. On the basis of chemical, differential thermal, infrared, Mössbauer, and X-ray powder diffraction analyses, Fe(II) seems to be present only in the 2:1 layer of the original chlorite in a type of site similar to that of Fe(II) in biotite, with OH in cis-positions. These data also suggest that octahedral Al and Fe(III) are located in the hydroxide sheet of the original chlorite. The structural changes of the mineral due to the oxidation and the subsequent reduction appear limited to minor structural rearrangements and, perhaps, to the introduction of OH in both cis- and trans-positions. The results of the investigation are in agreement with a reaction of the form: [Fe(II)OH]+ ⇋ [Fe(III)O]+ + H(H+ + e−).

Резюме

Резюме

Резюме—Хлорит богатый в железо, рипидолит, был окислен путем нагрева в воздухе при 480°С, то есть ниже температуры дегидроксиляции. Окисленный хлорит был последовательно восстанов-лен в водороде при такой же температуре. По данным химического, термодифференциального, инфракрасного, Мессбауеровского, и рентгеновского анализов кажется, что Fe(II) существует только в 2:1 слоях исходного хлорита в местах, похожих на те, которые Fe(II) занимает в биотите, с группами OH в положениях cis. Эти данные указывают также на то, что октаэдрические А1 и Fe(III) расположены в гидроокисных пластах исходного хлорита. Структурные изменения минерала, возникающие в результате окисления и последовательного восстановления кажутся быть ограниченными до небольших структурных перестроек, и, возможно до введения групп OH в обоих cis и trans положениях. Результаты исследований согласны со следующей формой реак-ции: [Fe(II)OH]+ ⇌ [Fe(III)O]+ + H(H+ + e−). [E.C.]

Resümee

Resümee

Ein eisenreicher Chlorit, Ripidolith, wurde durch Erhitzen auf 480°C an der Luft, (d.h. unter die Dehydratationstemperatur) oxidiert und anschließend im Wasserstoff bei der gleichen Temperatur reduziert. Aufgrund chemischer Analysen, Differentialthermo-, Infrarot-, Mössbauer- und Röntgendiffraktometer-Untersuchungen scheint das Fe2+ nur in der 2:1 Schicht des ursprünglichen Chlorites vorhanden zu sein, wobei die Art des Platzes, den das Fe2+ besetzt, dem des Fe2+ in Biotit ähnelt und das (OH) in cis-Stellung ist. Diese Ergebnisse deuten weiters darauf hin, daß oktaedrisches AI und Fe3+ in den Hydroxidschichten des ursprünglichen Chlorits sind. Die strukturellen Veränderungen des Minerals aufgrund der Oxidation und der darauffolgenden Reduktion scheinen auf geringe strukturelle Neuordnungen und, vielleicht, auf die Einführung von (OH) sowohl in cis-als auch in trans-Stellung beschränkt zu sein. Die Ergebnisse dieser Untersuchung stimmen mit folgender Reaktion überein: [Fe2+OH]+ ⇌ [Fe3+O]+ + H(H+ + e−). [U.W.]

Résumé

Résumé

Une chlorite riche en fer, la ripidolite, a été oxidée par échauffement à l'air à 480°C, c'est à dire sous la température de déshydroxylation, et la chlorite oxidée a subséquemment été réduite dans l'hydrogène à la même température. Basé sur des analyses chimiques, thermales différentielles, infrarouges, de Mössbauer, et de diffraction poudrée aux rayons-X, Fe(II) ne semble être présent que dans la couche 2:1 de la chlorite originale, dans un genre de site semblable à celui de Fe(II) dans la biotite, avec OH dans les positions-cis. Ces données suggèrent aussi qu'Al octaèdral et Fe(III) sont situés dans la feuille hydroxide de la chlorite originale. Les changements structuraux du minéral causés par T oxidation et la réduction subséquente semblent limités à des réarrangements mineurs, et peut-être à l'introduction d'OH dans les positions -cis et -trans. Les résultats de l'investigation s'accordent avec une réaction de la forme: [Fe(II)OH]+ ⇌ [Fe(III)O]++H(H+ + e−]. [D.J.]

Keywords

ChloriteInfrared spectroscopyIronMössbauer spectroscopyOxidationReduction
Type
Research Article
Information
Clays and Clay Minerals , Volume 30 , Issue 5 , October 1982 , pp. 353 - 363
Copyright
Copyright © 1982, The Clay Minerals Society

References

Addison, C. C., Addison, W. E., Neal, G. H. and Sharp, J. H., 1962 Amphiboles. Parti. The oxidation of crocidolite J. Chem. Soc 1468–1471.CrossRefGoogle Scholar
Bagin, V. I., Gengler, T. S., Dainyak, L. G. and Kuz’min, R. N., 1980 Mössbauer, thermomagnetic, and X-ray study of cation ordering and high-temperature decomposition in biotite Clays & Clay Mineral. 28 188–196.CrossRefGoogle Scholar
Bailey, S. W. and Gieseking, J. E., 1975 Chlorites Soil Components, Vol. 2, Inorganic Components New York Springer-Verlag 191–263.CrossRefGoogle Scholar
Bailey, S. W., Brindley, G. W. and Brown, G., 1980 Structure of layer silicates Crystal Structures of Clay Minerals and their X-ray Identification London Mineralogical Society 86–98.Google Scholar
Bernas, B., 1968 A new method for decomposition and comprehensive analysis of silicates by atomic absorption spectrometry Anal. Chem. 40 1682–1686.CrossRefGoogle Scholar
Blaauw, C., Stroink, G., and Leiper, W. (1980) Mössbauer analysis of talc and chlorite: J. Phys. 41, C1-411-412.Google Scholar
Borggaard, O. K., 1976 Selective extraction of amorphous iron oxide by EDTA from a mixture of amorphous iron oxide, goethite, hematite J. Soil Sci. 27 478–486.CrossRefGoogle Scholar
Borggaard, O. K., 1979 Selective extraction of amorphous iron oxides by EDTA from a Danish sandy loam J. Soil Sci. 30 727–734.CrossRefGoogle Scholar
Caillère, S., Hénin, S. and Mackenzie, R. C., 1957 The chlorite and serpentine minerals The Differential Thermal Investigation of Clays London Mineralogical Society 207–230.Google Scholar
Ericsson, T. and Wäppling, R. (1976) On texture effects in M1 3/2-1/2 Mössbauer spectra: J. Phys. 37, C6-719-723.Google Scholar
Ericsson, T., Wäppling, R. and Punakivi, K., 1977 Mössbauer spectroscopy applied to clay and related minerals Geol. Foren. Stockholm Förh. 99 229–244.CrossRefGoogle Scholar
Farmer, V. C. and Farmer, V. C., 1974 The layer silicates The Infrared Spectra of Minerals London Mineralogical Society 331–363.CrossRefGoogle Scholar
Farmer, V. C., Russell, J. D., McHardy, W. J., Newman, A. C. D., Ahlrichs, J. L. and Rimsaite, J. Y. H., 1971 Evidence for loss of protons and octahedral iron from oxidized biotites and vermiculites Mineral. Mag. 38 121–137.CrossRefGoogle Scholar
Gilkes, R. J., Young, R. C. and Quirk, J. P., 1972 The oxidation of octahedral iron in biotite Clays & Clay Mineral. 20 303–315.CrossRefGoogle Scholar
Goodman, B. A., Bain, D. C., Mortland, M. M. and Farmer, V. C., 1979 Mössbauer spectra of chlorites and their decomposition products Proc. Int. Clay Conference, Oxford, 1978 Amsterdam Elsevier 65–74.Google Scholar
Hayashi, H. and Oinuma, K., 1965 Relationship between infrared absorption spectra in the region of 450–900 cm−1 and chemical composition of chlorite Amer. Mineral. 50 476–483.Google Scholar
Hayashi, H. and Oinuma, K., 1967 Si-O absorption band near 1000 cm−1 and OH absorption bands of chlorite Amer. Mineral. 52 1206–1210.Google Scholar
Hayashi, H., Sano, H. and Shirozu, H., 1972 Mössbauer spectra of chlorites in natural and heated state Kobutsugaku Zassh. 10 507–516.Google Scholar
Hogg, C. S. and Meads, R. E., 1975 A Mössbauer study of the thermal decomposition of biotites Mineral. Mag. 40 79–88.CrossRefGoogle Scholar
Ingalls, R., 1964 Electric-field gradient tensor in ferrous compounds Phys. Rev. 133 787–795.CrossRefGoogle Scholar
Klug, H. P. and Alexander, L. E., 1974 X-ray Identification Procedures for Polycrystalline and Amorphous Materials. New York Wiley 356.Google Scholar
Makumbi, L. and Herbillon, A. J., 1972 Vermiculitisation expérimentale d’une chlorite Bull. Groupe Fr. Argile. 24 153–164.CrossRefGoogle Scholar
Post, J. L. and Plummer, C. C., 1972 The chlorite series of Flagstaff Hill Area, California: A preliminary investigation Clays & Clay Mineral. 20 271–283.CrossRefGoogle Scholar
Ross, G. J., 1975 Experimental alteration of chlorites into vermiculites by chemical oxidation Natur. 255 133–134.CrossRefGoogle Scholar
Ross, G. J. and Kodama, H., 1974 Experimental transformation of a chlorite into a vermiculite Clays & Clay Mineral. 22 205–211.CrossRefGoogle Scholar
Ross, G. J. and Kodama, H., 1976 Experimental alteration of a chlorite into a regularly interstratified chlorite-vermiculite by chemical oxidation Clays & Clay Mineral. 24 183–190.CrossRefGoogle Scholar
Rozenson, I. and Heller-Kallai, L., 1976 Reduction and oxidation of Fe3+ in dioctahedral smectites—1: Reduction with hydrazine and dithionite Clays & Clay Mineral. 24 271–282.CrossRefGoogle Scholar
Rozenson, I. and Heller-Kallai, L., 1976 Reduction and oxidation of Fe3+ in dioctahedral smectites—2: Reduction with sodium sulfide solutions Clays & Clay Mineral. 24 283–288.CrossRefGoogle Scholar
Russell, J. D., Goodman, B. A. and Fraser, A. R., 1979 Infrared and Mössbauer studies of reduced nontronites Clays & Clay Mineral. 27 63–71.CrossRefGoogle Scholar
Shirozu, H., 1958 X-ray powder patterns and cell dimensions of some chlorites in Japan, with a note on their interference colors Mineral. J. 2 209–223.CrossRefGoogle Scholar
Steinfink, H., 1958 The crystal structure of chlorite. I. A monoclinic polymorph Acta Crystallogr. 11 191–195.CrossRefGoogle Scholar
Taylor, G. L., Routsala, A. P. and Keeling, R. O., 1968 Analysis of iron in layer silicates by Mössbauer spectroscopy Clays & Clay Mineral. 16 381–391.CrossRefGoogle Scholar
Tripathi, R. P., Chandra, U., Chandra, R. and Lokanathan, S., 1978 A Mössbauer study of the effects of heating biotite, phlogopite and vermiculite J. Inorg. Nucl. Chem. 40 1293–1298.CrossRefGoogle Scholar
Vedder, W. and Wilkins, R. W. T., 1969 Dehydroxylation and rehydroxylation, oxidation, and reduction of micas Amer. Mineral. 54 482–509.Google Scholar
Veith, J. A. and Jackson, M. L., 1974 Iron oxidation and reduction effects on structural hydroxyl and layer charge in aqueous suspensions of micaceous vermiculites Clays & Clay Mineral. 22 345–353.CrossRefGoogle Scholar