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Oxidation of pyroaurite-like Ni-Fe hydroxychlorides studied by Mössbauer spectroscopy at 16 K

Published online by Cambridge University Press:  09 July 2018

Ph. Refait
Affiliation:
Laboratoire de Chimie Physique pour l'Environnement, UMR 7564 CNRS, Université Henri Poincar6 Nancy 1, France
M. Abdelmoula
Affiliation:
Laboratoire de Chimie Physique pour l'Environnement, UMR 7564 CNRS, Université Henri Poincar6 Nancy 1, France
J.-M. R. Génin
Affiliation:
405 rue de Vandoeuvre, F-54600 Villers-lés-Nancy, France

Extract

A recent article by Refait & Génin (1997) was devoted to Ni(II)-Fe(II)-Fe(III) pyroaurite-like hydroxychlorides obtained by aerial oxidation of mixed Ni(II)-Fe(II) hydroxides with various P = Fe/Ni ratios in chloride-containing aqueous solutions. Corresponding to the ideal composition Ni3-xIIFexIIFeIII(OH)8Cl.nH2O , the Fe(III)/[Ni(II)+Fe(II)] ratio is 1/3 when P is >1/3. These hydroxyehlorides oxidize quickly and the final product depends on P. In the absence of nickel, P = ∞, FeII3FeIII(OH)8Cl.nH2O, known as Green Rust one (Bemal et al, 1959) oxidizes into γ-FeOOH. When P is >5/3, the X-ray diffraction (XRD) analyses of the end-product reveal lepidocrocite and some Ni(II)-Fe(III) hydroxychloride.

Type
Notes
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1998

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