Mineralogical characterization of arsenic in uranium mine tailings precipitated from iron-rich hydrometallurgical solutions

Moldovan, B. J., Jiang, D.T. and Hendry, M. J. (2003) Mineralogical characterization of arsenic in uranium mine tailings precipitated from iron-rich hydrometallurgical solutions. Environmental Science and Technology, 37(5), pp. 873-879. (doi: 10.1021/es025947a)

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Abstract

Arsenic-rich uranium mine tailings from the Rabbit Lake in-pit tailings management facility (RLITMF) in northern Saskatchewan, Canada, were investigated to determine the mineralogy and long-term stability of secondary arsenic precipitates formed from iron-rich hydrometallurgical solutions. Total arsenic and iron concentrations in six iron-rich samples of the mine tailings ranged from 56 to 6000 μg/g and from 12 600 to 30 200 μg/g, respectively (Fe/As molar ratios of 5.3−303). On the basis of stability field diagrams generated from pH, Eh, and temperature measurements on tailings samples (mean values of 9.79, +162 mV, and 2.8 °C, respectively), it was concluded that arsenic and iron in the tailings were stable as As5+ and Fe3+. Synchrotron-based X-ray absorption spectroscopic studies of tailings samples, fresh mill precipitates, and reference compounds showed that the arsenic in iron-rich areas of the tailings existed as the stable As5+ and was adsorbed to 2-line ferrihydrite through inner-sphere bidentate linkages. Furthermore, under the conditions in the RLITMF, the 2-line ferrihydrite did not undergo any measurable conversion to more crystalline goethite or hematite, even in tailings discharged to the RLITMF 10 yr prior to sampling.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Hendry, Professor Martin
Authors: Moldovan, B. J., Jiang, D.T., and Hendry, M. J.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Environmental Science and Technology
Journal Abbr.:EST
Publisher:American Chemical Society
ISSN:0013-936X
ISSN (Online):1520-5851
Published Online:05 February 2003

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