Green and short preparation of CeO₂ nanoparticles with large specific surface area from rare earth extraction (CeCl₃) was successfully achieved by spray pyrolysis (SP). In this method, a precursor solution is first prepared by mixing CeCl₃, C₆H₈O, and H₂O in the requisite quantities. Subsequently, the precursor consisting of a mixture of CeO₂ and C was obtained by SP method by using the precursor solution. Finally, the calcination at 500 °C~800 °C in air for two hours to transform the precursor to CeO₂ nanoparticles. Thermodynamic analysis and experimental studies were performed to determine the optimal SP temperature and citric acid amount. The results indicated that the maximum specific surface area (59.72 m²/g) of CeO₂ nanoparticles were obtained when the SP temperature was 650 °C and the molar ratio of citric acid to CeCl₃ was 1.5.

Yttrium–magnesium alloys are commonly employed as processing additives in magnesium alloy materials. Incorporating yttrium into magnesium alloys via Y-Mg intermediate alloys not only minimizes oxidation and burn-off loss but also simplifies operational procedures. Utilizing yttrium–magnesium alloys ensures a stable composition and reliable quality of magnesium alloy products, while contributing to reduced production costs and minimized environmental pollution. In this study, a molten salt co-reduction method was developed for the preparation Y-Mg intermediate alloys. The electrochemical co-reduction behaviors of Y(III) and Mg(II), as well as the transient states of Y-Mg intermediate alloys, were systematically investigated by transient electrochemical techniques. Results indicated that the reduction of Y(III) at the molybdenum (Mo) cathode is a reversible electrochemical process, whereas the reduction of Mg(II) is irreversible and diffusion-controlled. The diffusion coefficient of Y(III) and Mg(II) in the fluoride salt at 1000 °C were determined to be 3.98 × 10⁻⁵ cm²/s and 1.16 × 10⁻³ cm²/s, respectively. Electrochemical calculations revealed that the reduction of Y(III) involves a single-step transfer of three electrons, while Mg(II) involves a single-step transfer of two electrons. The corresponding electrode reactions are Y(III) + 3e⁻→Y and Mg(II) + 2e⁻→Mg, respectively. A Y-Mg alloy sample prepared by constant-current molten salt electrolysis primarily consists of the MgY phase with a composition of 88.38 wt% yttrium and 11.62 wt% magnesium.

Iron beneficiation tailings from the Bayan Obo West Mine constitute a low-grade secondary rare-earth resource in which rare-earth minerals are finely disseminated and intricately intergrown with gangue. This study quantified the modes of occurrence of rare-earth minerals and assessed an integrated flowsheet comprising screening, magnetic separation, and flotation. The feed contained 1.32 wt.% rare-earth oxides (REOs), as determined by X-ray fluorescence spectrometry (XRF) and inductively coupled plasma optical emission spectrometry (ICP-OES). X-ray diffraction (XRD), scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS), and automated mineralogy (AMICS) further showed that monazite and bastnäsite hosted 47.39% and 39.19% of the total REOs, respectively. Screening at 74 μm rejected 32.60% of the feed as a coarse fraction containing 0.65 wt.% REOs. Subsequent wet high-intensity magnetic separation reduced the mass entering flotation to 54.35% of the original feed while retaining 74.94% of the feed REOs and increasing the REO grade to 1.82 wt.%. Closed-circuit flotation with one rougher and three cleaner stages yielded a concentrate containing 51.99 wt.% REOs at an overall recovery of 52.38%. Rare-earth minerals accounted for 82.55 wt.% of the concentrate, including 41.65 wt.% monazite and 33.96 wt.% bastnäsite. This study thus demonstrated the feasibility of producing a high-grade rare-earth concentrate from the low-grade, fine-grained iron beneficiation tailings of the Bayan Obo West Mine characterized by complex mineral intergrowths, providing a practical basis for further rare-earth beneficiation and flowsheet optimization.

Molten salt electrolysis stands as an indispensable technique for the production of rare earth metals, where the judicious distribution of the electric field within the electrolytic cell is paramount for ensuring the seamless operation of the electrolysis process. This study introduces a pioneering approach by integrating the Nernst-Planck equation with the Butler-Volmer equation, thereby devising a holographic electric field model tailored for the electrolysis of the NdF3-LiF molten salt system. The paper presents pioneering experimental measurements concerning the potential distribution and voltage drop characteristics within a 6kA rare earth electrolytic cell, elucidating the interplay between decomposition voltage and current density, which substantiates the model's precision. Our findings unveil that, under operational conditions of 4010 amperes, the 6kA electrolytic cell incurs a total voltage drop of 6.3 volts, delineating a melt voltage drop of 4.43 volts, an ohmic voltage drop of 0.248 volts, and an interfacial voltage drop of 1.622 volts at the electrode-electrolyte junction. The discrepancy in error is confined to within 0.3% of the actual measured voltage of 6.28 volts.The simulation outcomes from the holographic electric field model have been confirmed to precisely and comprehensively reflect the characteristics of the electric field distribution during the rare earth molten salt electrolysis process, offering valuable theoretical insights for practical manufacturing applications.