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Open AccessArticle

Automated SEM Mineral Liberation Analysis (MLA) with Generically Labelled EDX Spectra in the Mineral Processing of Rare Earth Element Ores

1
Institut für Mineralogie, Lagerstättenlehre und Petrologie, TU Bergakademie Freiberg, Brennhausgasse 14, D-09596 Freiberg/Sachsen, Germany
2
Merker Mineral Processing, Oertenroeder Str. 21, D-35329 Gemuenden, Germany
3
Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz-Institut Freiberg für Ressourcentechnologie, Chemnitzer Str. 40, D-09599 Freiberg/Sachsen, Germany
*
Author to whom correspondence should be addressed.
Minerals 2019, 9(9), 527; https://doi.org/10.3390/min9090527
Received: 9 August 2019 / Revised: 28 August 2019 / Accepted: 29 August 2019 / Published: 30 August 2019
Many rare earth element (REE) deposits have experienced multistage geological enrichment processes resulting in REE bearing mineral assemblages of considerable complexity and variability. Automated scanning electron microscopy (SEM) mineral liberation analysis of such REE ores is confronted by the difficult assignment of energy-dispersive X-ray (EDX) spectra to REE mineral names. To overcome and bypass this problem, a generic and reliable labelling of EDX reference spectra obtained from REE-bearing minerals based on their contents of Si, Ca, F and P in a bulk normalised analysis is proposed. The labelled spectra are then combined into groups of REE-P (~monazite), REE-Ca-Si-P (~britholite), REE-Ca-F (~synchysite) and REE-F (~bastnaesite, parisite, fluocerite). Mixed spectra with low counts for REE from minute REE mineral grains are combined into a separate group. This classification scheme is applied to automated SEM mineral liberation analysis (MLA) data from beneficiation products by comminution and multistage flotation of REE carbonatite ores. Mineral modes, mineral grain size distribution, mineral liberation, mineral locking and mineral grade versus recovery curves based on the analysis of >200,000 particles in a sample can be recognised and interpreted in virtual grain size fractions. The approach as proposed here will allow future process mineralogical studies of REE deposits to be robust and comparable. View Full-Text
Keywords: REE minerals; REE carbonatite ore; comminution; multi-stage flotation; EDX spectra REE minerals; REE carbonatite ore; comminution; multi-stage flotation; EDX spectra
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MDPI and ACS Style

Schulz, B.; Merker, G.; Gutzmer, J. Automated SEM Mineral Liberation Analysis (MLA) with Generically Labelled EDX Spectra in the Mineral Processing of Rare Earth Element Ores. Minerals 2019, 9, 527.

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