Characterization of Uranium, Thorium and Rare Earths in the Decomposition Process of Thai Monazite Ore Samples by X Ray Powder Diffraction and Wavelenght Dispersive X Ray Fluorescence Techniques

Monazite ore found in the tailings from tin mining in southern Thailand has been used as source of REEs, uranium and thorium. The decomposition process using alkali method, solvent extraction and ion exchange techniques were used to separate and purify those elements. XRD and WD-XRF as fast, accurate and nondestructive methods were extremely useful for the determination of REE, uranium, thorium and associated mineral concentrations in the samples obtained during the process. The elemental compositions of all samples measured by WD-XRF agreed well with that determined by the XRD method. In addition, the concentration of uranium oxide in the U₃O₈ cake sample determined by WD-XRF (87.77 wt%) showed very good agreement with that obtained by the XRD method (87.00 wt%). The same result was obtained for the CeO₂ sample, with concentrations of 99. 47 wt% and 99.90 wt% detected by WD-XRF and XRD, respectively.