Resumo

MOILA, A.; CHETTY, D.  e  NDLOVU, S.. The application of process mineralogy on a tailings sample from a beach placer deposit containing rare earth elements. J. S. Afr. Inst. Min. Metall. [online]. 2017, vol.117, n.7, pp.615-621. ISSN 2411-9717.  http://dx.doi.org/10.17159/2411-9717/2017/v117n7a2.

The rare earth elements (REE) are significant in the context of world economic growth and modern technology. This research is aimed at investigating an alternative source of REE by exploring cost-effective ways of processing REE minerals from an existing beach placer deposit operation, currently mined for titanium. In order to recover REE through economically optimum means, upfront mineralogical investigations are a necessity to reduce the ore processing costs. An approach involving mineralogical characterization and hydrometallurgical test work was therefore chosen. The sample for the study - a tailings fraction from a heavy mineral concentration plant in the titanium industry - was screened into four size classes, and each size class was mineralogically characterized. The minerals present in the sample were monazite, zircon, epidote, pyroxene, amphibole, rutile, quartz, leucoxene, titanite, and almandine. The main REE-bearing minerals, monazite and zircon, were preferentially concentrated in the finer (-150 μm) fractions, which constituted about 50 mass % of the sample and which would be amenable to direct leaching without prior upgrading to a concentrate. Leaching test work was carried out on the combined fractions passing 150 μmι. Mineralogical examination of the residues from different leach stages showed that monazite was cracked and the REE released to solution in the final leach stage. Zircon was not as reactive under the conditions used, and REE release was not expected from this mineral. The mineralogical findings were correlated against bulk chemical analyses of the leach products to establish whether a good reconciliation was achieved

Palavras-chave : rare earth elements; beach placer deposit; process mineralogy; leaching.

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