Integrated purification of gadolinium and preparation of Gd2O3 nanoparticles by DC arc plasma

The rare-earth metal Gd plays an important role in the energy, information, and national defence fields due to its special optical, electrical, magnetic, and catalytic properties. In this study, Gd was purified by direct current (DC) arc plasma, and Gd2O3 nanoparticles were prepared via an integration method using purified Gd. The effects of arc current, melting time, gas pressure, and atmosphere on the purification of Gd by DC arc plasma were investigated. With an increase in the arc current and melting time, the rate of removal of impurities from Gd enhances. Moreover, Gd melting was conducted by H2–Ar arc plasma, which improves the impurity removal rate by increasing the H2 content. High thermal conductivity and chemical activity of the activated H atoms generated by the dissociation of H2 are the main reasons for the significant improvement in the impurity removal rate. The mechanism of Gd purification was analysed based on the above-mentioned experimental results. The as-synthesised Gd2O3 nanoparticles have a uniform spherical structure (average diameter of 32.7 nm), appropriate dispersibility, and high purity. This study provides a new strategy for the integrated purification of metals and preparation of metal/metal-based nanomaterials by DC arc plasma.