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Dissolution of Cr2O3(s) and the behavior of chromium in concentrated NaOH solutions

Zydorczak, B., May, P.M., Meyrick, D.P., Bátka, D. and Hefter, G. (2012) Dissolution of Cr2O3(s) and the behavior of chromium in concentrated NaOH solutions. Industrial & Engineering Chemistry Research, 51 (51). pp. 16537-16543.

Link to Published Version: http://dx.doi.org/10.1021/ie302096e
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Abstract

The solubility of Cr2O3(s) in (1 and 6) mol kg -1 sodium hydroxide solutions has been investigated at 25°C. Even after 75 days of solid/solution contact the apparent solubility continued to increase slowly. Analysis of the solution phase by UV-vis spectrophotometry revealed that all of the dissolved chromium was present as Cr(VI), in the form of CrO4 2-(aq); no Cr(III) could be detected. Consistent with this finding, Cr(III) dissolved in 6 mol kg-1 NaOH was found to be oxidized to CrO4 2-(aq) over of period of days. No significant changes to the solid phase, Cr2O3(cr), were found, either by X-ray diffraction or by X-ray photoelectron spectroscopy, as a result of its contact with NaOH(aq). Both CrO4 2- and Cr(III) were found to be unreactive toward a range of organic and inorganic compounds in 6 mol kg-1 NaOH over many days at ambient temperatures. However, CrO4 2- catalyzed the decomposition of L-ascorbate, and was rapidly reduced by elemental Zn to Cr(III) in NaOH(aq).

Publication Type: Journal Article
Murdoch Affiliation: School of Chemical and Mathematical Science
Publisher: American Chemical Society
Copyright: © 2012 American Chemical Society.
URI: http://researchrepository.murdoch.edu.au/id/eprint/12588
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