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The reductive dissolution of synthetic goethite and hematite in dithionite

Published online by Cambridge University Press:  09 July 2018

J. Torrent
Affiliation:
Departamento de Ciencias y Recursos Agricolas, Escuela Técnica Superior de Ingenieros Agrónomos, Apdo. 3048, 14080 Córdoba, Spain
U. Schwertmann
Affiliation:
Institut für Bodenkunde, Technische Universität München, 8050 Freising-Weihenstephan, Federal Republic of Germany
V. Barron
Affiliation:
Departamento de Ciencias y Recursos Agricolas, Escuela Técnica Superior de Ingenieros Agrónomos, Apdo. 3048, 14080 Córdoba, Spain

Abstract

The reductive dissolution by Na-dithionite of 28 synthetic goethites and 26 hematites having widely different crystal morphologies, specific surfaces and aluminium substitution levels has been investigated. For both minerals the initial dissolution rate per unit of surface area decreased with aluminium substitution. At similar aluminium substitution and specific surface, goethites and hematites showed similar dissolution rates. These results suggest that preferential, reductive dissolution of hematite in some natural environments, such as soils or sediments, might be due to the generally lower aluminium substitution of this mineral compared to goethite.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1987

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