Zirconium and hafnium are critical transition metals for nuclear and aerospace applications. To ensure a sustainable supply, the successful refining of technogenic zirconium scrap and primary hafnium sponge is essential. Our study investigates the high-efficiency purification of these materials using Electron Beam Melting (EBM) method at operating temperatures of 2350 K and 2550 K for the zirconium specimens, and 2700 K and 2900 K for the hafnium material. These temperatures correspond to overheating above the respective melting points of both metals (Tm,Zr = 2125 K, Tm,Hf = 2506 K) by approximately 200 K and 400 K. Based on conducted thermodynamic and experimental studies, results were obtained for the quality of the metals and correlations between EBM technological parameters (overheating melting temperature and refining time) and impurity removal degree were established. The obtained results prove that by overheating both refractory materials by 200 K and 400 K (above their melting points), high-vapor-pressure metallic impurities and specific oxides (such as NiO, FeO, TiO₂, Cr₂O₃) are effectively removed by evaporation and distillation. Despite the significant difference in the melting points of the studied metals (Zr and Hf), at both degrees of overheating, a substantial difference in the removal rate of metallic impurities was observed only for aluminum. To compare the behaviors of Hf as an impurity in Zr material and Zr as an impurity in hafnium, the relative volatilities were also calculated, revealing that hafnium impurity cannot be degassed from zirconium base metal, while separating zirconium impurity from hafnium base material risks base-metal loss. Experimental study and metallographic observations confirm the thermodynamically proposed removal mechanisms, showing that higher overheating leads to highly effective EBM refining in the resulting ingots that is essential for producing pure zirconium and hafnium materials for advanced high-technology industries.
