Comparative analysis of impurity removal in aluminum, copper, and nickel by hydrogen refining

This study investigates the effects of vacuum and hydrogen atmospheres on the removal of metallic and nonmetallic impurities during zone melting of Al, Cu, and Ni. The results show that while hydrogen had minimal impact on metallic impurity removal, it significantly enhanced the elimination of non-metallic impurities, particularly oxygen, in Cu and Ni. The introduction of hydrogen reduced oxygen levels by over 95 % in Ni and 44 % in Cu, and also improved the removal of carbon and sulfur. However, in Al, hydrogen refining proved less effective due to the stability of Al2O3 and the tendency of Al to form hydrides.