Selective Precipitation of Th and Rare-Earth Elements from HCl Leach Liquor

In this study, selective precipitation of thorium and rare-earth elements was investigated. The leach liquor contains Th, Ce, La, Nd, Pr, and Sm. Precipitation process was realized by using oxalic acid and selectivity of process was provided with the addition of oxalic acid at different volumes. The concentration of oxalic acid and settling duration were selected as parameters. The pH change of leach liquor was controlled during the experiments. The precipitation order was identified as Th, Sm, Nd and Pr, Ce, and La due to increasing of the oxalic acid volume. The precipitation efficiencies were calculated with remaining metals in leach liquor. The elemental analysis of solutions was realized with Inductively Coupled Plasma-Optical Emission Spectrometer (ICP-OES), and the phase analysis of the precipitates was realized with X-ray diffractometer (XRD).