Dissolution and Online Monitoring of Nd and Pr Oxides in NdF3–PrF3–LiF Electrolytes

Concentrations of dissolved rare earth metal oxides, Nd2O3, and Pr2O3 or their mixtures in different fluoride electrolytes composed of NdF3, PrF3, and LiF at ca. 1040 °C were monitored using a graphite probe inserted into the electrolyte during the dissolution process. Fast voltage sweeps of 100 V/s were applied to the graphite probe, and the current response was measured. As the oxide concentration in the diffusion layer towards the electrode depletes, a passive layer is, at a certain point, formed on the probe, resulting in a current drop. The magnitude of the peak current attained before the formation of the passive layer reflects the concentration of the dissolved oxide and, thus, is applied to determine the oxide concentration. The oxide concentration in the electrolyte samples determined using the inert gas fusion technique showed a good correlation to the peak current determined by the probe.

Synthesis of Rare Earth Metal Oxides Based on Monasite Sand with pH Variations

In the island of Bangka Belitung, the presence of monazite is quite abundant, monazite minerals contain rare earth metals. Rare Earth Metals are groups of elements that have similar properties, for example neodymium, cerium, lanthanum, and others. Rare earth metal applications are very potential in various fields. In this research, the synthesis of rare earth metals by sol gel method at pH variations of 5.5, 6.5 and 7.5 was carried out. In this case, only changes in the levels of P2O5, La2O3, CeO2, and Nd2O3 compounds were observed. The results showed an increase in levels of rare earth metals. This is indicated by the increase in La2O3 levels by 4,421% from the initial level at pH 7.5 CeO2 which has increased levels by 7,166% at pH 7.5, and Nd2O3 which has increased levels of 5.116% at pH 6.5. On the other hand, of P2O5 has decreased significantly (22.037%) Keyword: Monasite, Rare Earth, Sol Gel, pH