Quantification of radionuclide distribution and migration during Cu-(Fe)-sulphide mineral processing by alpha particle autoradiography

Understanding the movement of radionuclides (RNs) between different mineral hosts during processing of base metal ores is critical for accurate modelling of RN deportment and optimisation of processes designed to reduce or eliminate RNs. Here, we demonstrate that spatially resolving quantitative alp...

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Bibliographic Details
Published in:	Journal of environmental radioactivity 2021-03, Vol.228, p.106514, Article 106514
Main Authors:	Kalnins, Christopher A.G., Ottaway, David, Cook, Nigel J., Spooner, Nigel A.
Format:	Article
Language:	eng
Subjects:	Alpha Particles Alpha-particle autoradiography Autoradiography Barite Bornite Copper sulphides Covellite High- resolution mapping Mineral processing Minerals - analysis Radiation Monitoring Radioisotopes Radionuclides Sulfides
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Summary:	Understanding the movement of radionuclides (RNs) between different mineral hosts during processing of base metal ores is critical for accurate modelling of RN deportment and optimisation of processes designed to reduce or eliminate RNs. Here, we demonstrate that spatially resolving quantitative alpha particle autoradiography combined with backscatter electron imaging and energy dispersive X-ray spectroscopy (EDS) can establish the correlation between alpha-emitting RNs (notably 226Ra and 210Po, daughters of the abundant 238U decay series) and certain minerals, in different stages of processing. This is achieved by locating the RNs to a specific mineral grain, the species of which can subsequently be identified using EDS. The mineralogy of RN-associated grains can then be compared with the mineral suite and relative abundances of the species within the sample, by relating how often each mineral is associated with alpha decay-events. In the processing of uranium-bearing copper ores, migration of alpha-emitting RN daughters of the 238U series were observed, and these RNs were demonstrated to correlate strongly with barite, bornite and covellite over other coexisting minerals. •Alpha-particle autoradiography can locate alpha-emitting radionuclide bearing grains at micron-scale spatial resolution.•The associations of radionuclides with specific minerals were quantified.•Radionuclide migration was traced through sequential mineral processing stages.•Alpha-particle emitting radionuclides were incorporated in Cu-(Fe)-sulphides during sulphide leaching.
ISSN:	0265-931X 1879-1700