Development of A Novel Production Process of High Purity Niobium for Electron Particle Accelerator

采用熔盐电解和电子束熔融法制备了电子粒子加速器材料中的粗铌。在氩气气氛下，用氟立克液（质量为26.3质量% liff -10.5质量%NaF-47.0质量%KF-16.2质量%K_2NbF_7）在963 K条件下进行了恒流电精炼熔盐。经过熔盐电子精炼和电子束熔化，用ICP发射光谱法测定了纯化铌中金属杂质组分的含量。采用熔盐电精炼的方法可以去除粗铌中的钽、钨、钼等难熔金属。特别是采用熔盐电精炼法对粗铌中金属钽的脱除效果显著。电子束熔炼也可去除氧、氮等非金属杂质成分。用此工艺可制得纯度为99.8质量%的粗铌，达到99.99质量%。

Crude niobium has been purified by a refining process consistiong of molten salt electrolysis and electron beam melting for materials of electron particle accelerator. The molten salt electronrefining was carried out galvanostatically using a FLINAK bath (26.3 mass% Lif-10.5 mass%NaF-47.0 mass%KF-16.2 mass%K_2NbF_7 at 963 K under Ar atmosphere. After the molten salt electronrefining and the electron beam melting, the contents of metallic impurity components in the purified niobium were determined by ICP emission spectrography analysis. Refractory metals such as tantalum, tungsten and molybdenum in crude niobium could be eliminated by means of molten salt electrorefining. Especially, the molten salt electrorefining method using fluoride bath was remarkably effective for the removal of merallic tantalum in crude niobium. Nonmetallic impurity components such as oxygen and nitrogen could be also remove by electron beam melting.Crude niobium of 99.8 mass% purity was found to be to 99.99 mass% by this process.