Leaching behaviour and particle interactions in uranium laterite dispersions: effect of ore mineralogy and temperature
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(Published version)
Date
2012
Authors
Nosrati, A.
Maccarthy, J.
Skinner, W.M.
Addai Mensah, J.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Conference paper
Citation
Proceedings of the international mineral processing congress, 2012, iss.192, pp.3882-3892
Statement of Responsibility
Conference Name
26th International Mineral Processing Congress, IMPC 2012 (24 Sep 2012 - 28 Sep 2012 : New Delhi, India)
Abstract
Due to complex mineralogical and chemical interactions of the value and gangue mineral phases present in uranium-containing lateritic ores, deleterious pulp gelation which impacts on value metal recovery sometimes occur during atmospheric leaching. In this study, the leaching behavior and particle interactions of selected oxide (hematite, quartz) and clay minerals (muscovite, chlorite), which constitute predominant host gangue phases of typical lateritic uranium ores are investigated to provide basic, mechanistic understanding of temporal pulp gelation phenomenon. Isothermal, batch leaching with H 2SO4 was carried out on concentrated dispersions (30 - 57 wt.%) of single minerals at pH 1 and 25 or 70 °C and their concomitant solution, speciation and rheology (shear yield stress, viscosity) were characterized. It is clearly shown that despite the high oxide content of lateritic ores, the pulp chemistry and rheology is largely affected by the incongruent leaching behavior of more reactive, acid-consuming aluminosilicate clays. Furthermore, time- and temperature-dependent alumino-silicate species polycondensation interfacial reactions are shown to be responsible for the enhanced particle interactions, reflecting strong pulp rheology in agitation and pumping. If not properly mitigated, high pulp shear yield stress and viscosity have a striking impact on processability and hence, value metal recovery.