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Title: Management of wastes from the processing of rare earth minerals
Authors: Hart, KP
Levins, DM
Keywords: Australia
Internal conversion radioisotopes
Lead 210
Ore processing
Radioactive waste processing
Rare earths
Issue Date: 28-Aug-1988
Publisher: Institution of Engineers Australia
Citation: Hart, K. P., & Levins, D. M. (1988). Management of wastes from the processing of rare earth minerals. Paper presented to Chemeca '88 : Australia's Bicentennial International Conference for the Process Industries, Sydney, 28-31 August 1988, (pp. 82-88).
Abstract: Australia is the leading producer and exporter of the rare earth mineral, monazite, but currently does not process it beyond the physical beneficiation stage. Recent discoveries of new uses for rare earth has renewed interest in monazite processing in Australia. Two proposals of rare earth processing plants have been announced and a number of other companies are engaged in feasibility studies. Chemical processing of monazite involves digestion in caustic soda to 'crack' the phosphate matrix, dissolution of the rare earths in acid and their separation by multi-stage solvent extraction usually in mixer-settlers. The processing is complicated by the presence of 4-8 wt% thorium and 0.1-0.3 wt% uranium in the monazite. Experiments have shown that lead-210 and uranium are partially solubilized in the caustic digestion stage and radium is dissolved along with the rare earths. Over 99.5% of the radium can be precipitated as barium/radium sulphate by the addition of barium chloride and soluble sulphate. This radium-bearing solid waste can be combined with the uranium/thorium residue so that essentially all the radionuclides are contained in the one waste stream. The volume of this waste stream is not large and it is feasible to store it on-site in an engineered facility. The safe disposal of this waste would be facilitated by the establishment of a national facility for radioactive and other toxic wastes.
Description: Physical copy held by ANSTO Library at DDC 660.20994/7
ISBN: 0858254093
Appears in Collections:Conference Publications

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