Characterization of Malaysian Monazite Concentrate for the Recovery of Thorium Dioxide

Abstract

Malaysia has many potential mineral resources including some heavy and light rare earth element (HREE and LREE's) minerals, such as Monazite and Xenotime. Their occurrence is in association with ores containing phosphates and oxides of Cerium (Ce), Lanthanum (La), Neodymium (Nd) and Thorium (Th). Mineralogical characterization of Malaysian Monazite concentrate for the recovery of Thorium dioxide (ThO2) has been carried out in this study. Scanning Electron Microscope (SEM) equipped with an Energy Dispersive X-ray Analyser (EDX) was used to assess the morphology and elemental composition of the mineral. The latter analysis showed that EDX surface analysis detected P-Kα Th-Mα, La-Lα, Ce-Lα and Nd-Lα as the major elements. The SEM micrographs with the EDX analysis revealed the morphological characteristics of Monazite which showed angled and irregular structures with dark coloured patches of Al, Si and Mn based inclusions. XRF analysis confirmed the presence of Th (8.52 wt.%) and U (0.25 wt.%). XRF also showed that the major rare earth elements (REE) of interest (> 5 wt.%) such as Ce, Nd and La were abundant in the mineral. XRD analysis identified LaPO4, CePO4 and NdPO4 as the major phases. Thorium phosphate (Th4(PO4)4) phase was not detected via XRD due to stronger X-ray reflection from the rare earth phosphates. The information collected from this study will help in developing a suitable process of treatment for the local Monazite, thereby facilitating the mineral to be used a domestic source of Th and other associated REE's.