钒合金真空精炼过程杂质元素去除研究

Calculation of Impurities Removal from Vanadium Alloy by Vacuum Refining

核能用钒合金要求纯净度极高,一般都要进行真空熔炼去杂质,但目前对钒合金真空熔炼去杂质的条件和机制还不很清楚。为此,本文对钒合金真空熔炼过程杂质元素的去除机制和热力学条件进行了较全面的理论计算和实验数据对比分析,结果表明:钒合金真空熔炼过程中,Al、Fe、Cr、Cu、Ni、Si、Ca、Ti等金属杂质元素都能以金属蒸汽的形式挥发去除;合金中的氧能够以碳氧化物或低价金属氧化物VO(g)、AlO(g)、Al_2O(g)、TiO(g)、SiO(g))形式除去;合金中氢的除去效果也比较好,但合金中的氮则基本不能通过真空熔炼除去。

The evaporationof the impurities,including Al,Fe,Cr,Cu,Ni,Si,Ca,Ti,as well as H,C,O and N,in vacuum refining of vanadium alloy（ a nuclear-reactor wall material）,was mathematically modeled,theoretically analyzed in thermodynamics and experimentally evaluated. The influence of the refining conditions on V-alloy purification was investigated. The calculated results show that except N,most impurities can be effectively removed by vacuum refining. To be specific,as the temperature increased in electron beam refining,the evaporation rates of the metallic impurities increased. Most metallic impurities were evaporated in the form of metals vapor; and O and C impurities were removed as gas-phased metal oxides and carbides,such as VO（ g）,AlO（ g）,Al_2O（ g）,TiO（ g）,SiO（ g）. H and N were found to be the easiest and the most difficult impurities to remove,respectively,in vacuum refining of V-alloy. The calculated and measured results were in fairly good agreement.