The Impact of Electron Beam Melting on the Purification of Recycled Zirconium

Zirconium belongs to the group of critical rare metals and is primarily used in industry. Its most important application, as the basis for specialized alloys, is in nuclear reactors, owing to its exceptionally very low thermal neutron absorption cross-section. Based on theoretical and experimental investigation, the potential for removing metallic (Al, Ti, Hf, V, Fe, Cr, Cu, Ni) and non-metallic (O, C) impurities from technogenic zirconium during electron beam melting (EBM) was assessed. The influence of temperature (ranging from 2350 K to 2750 K) and refining duration (10, 15, and 20 min) under vacuum conditions (1 × 10−3 Pa) was investigated concerning the degree of impurity removal, the microstructure, and the micro-hardness of the resulting ingots. It was established that under optimal EBM conditions for technogenic zirconium (T = 2750 K, τ = 20 min), the total refining efficiency reached approximately 87%, and the achieved Zr purity was 99.756%. Among the impurities present in the technogenic zirconium, the lowest removal efficiencies were recorded for Al (54.90%) and Cr (88.89%), with the lower refining efficiency for Al influencing the microstructure and micro-hardness of the ingots produced after EBM.