Abstract
Monazite , a rare earth and thorium phosphate mineral, is one of the major minerals processed for extraction of rare earths . Industry practice for treating monazite concentrates is to use either a sulfuric acid bake or caustic conversion route. In the sulfuric acid bake, monazite concentrate is mixed with concentrated sulfuric acid and roasted. The rare earth phosphate mineral is converted to rare earth sulfate which dissolves in a subsequent water leach . As the bake temperature increases above 300 °C, thorium becomes less soluble. Although acid baking is practised in industry, the bake reactions are not well understood. A combination of chemical analysis, XRD and SEM -EDS was used to identify reaction processes occurring during sulfuric acid baking of a 93 wt% monazite concentrate between 200 °C and 800 °C. The effects of these reactions on the leachability of the rare earths , thorium and phosphate were also examined.
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Acknowledgements
This work was funded by an Australian Government Research Training Program (RTP) scholarship to John Demol for PhD research through Murdoch University and by ANSTO Minerals , and conducted at ANSTO.
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Demol, J., Ho, E., Senanayake, G. (2018). Sulfuric Acid Baking and Leaching of Rare Earth Elements, Thorium and Phosphate from a Monazite Concentrate. In: Davis, B., et al. Extraction 2018. The Minerals, Metals & Materials Series. Springer, Cham. https://doi.org/10.1007/978-3-319-95022-8_197
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DOI: https://doi.org/10.1007/978-3-319-95022-8_197
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