PROPER CHARACTERIZATION OF THE REE MINERALOGY AND IMPLICATIONS IN
MINERAL PROCESSING
ABSTRACT
Exploration activity for rare earth element (REE) deposits (i.e., alkaline complexes, carbonatites) has
increased significantly in the last decade. A number of deposits have been evaluated around the globe.
However, no new operations are commenced except for re-openings in Western Australia and USA.
Resource estimation of REE can follow similar guidelines to other metal projects.
However, the inherent mineralogical characteristics of the REE deposits, despite their complex nature,
have been overlooked by many exploration companies. Each deposit appears to be different in terms of
matrix and REM (rare earth minerals). Light REE bearing minerals such as allanite, monazite, bastnäsite,
synchysite, and HREE such as fergusonite, xenotime can vary widely in chemistry, grain size and
association (e.g., carbonates or hard silicates). On the other hand, although not really REM, zircon, Zrsilicates, titanite, fluorite, apatite, and in some cases common silicate minerals can carry trace to significant
concentrations of REE.
An evaluation of REE deposits should include a proper mineralogical characterization including the
quantification of REM, distribution, liberation and association e.g., by quantitative mineralogical
techniques such as the QEMSCAN, chemistry of the REM by electron probe micro analysis and Laser
Ablation ICP-MS.
These techniques provide valuable data for geological purposes, i.e., define quantitatively the variability
and distribution of the REM; differentiate between LREE and HREE zones to delineate the ore; and
metallurgical purposes to predict minerals/REE behaviour during processing.
The lack of proper mineralogical characterization often leads to the wrong mineral recovery and processing
path and is extremely costly.
KEYWORDS
Rare Earth Elements, QEMSCAN, mineral processing