【摘要】 运用气体分子碰撞模型,研究了实际真空蒸馏金属的蒸发速率,对分子蒸馏状态下导出的金属蒸发速率Langmuir公式进行修正,并用金属镝、铽及铝做蒸馏蒸发速率实验研究,其蒸馏规律与修正后的Langmuir公式相符合,这一结果对蒸馏法制备高纯稀土金属具有实用价值,同时对探索其它金属蒸馏规律具有指导意义。更多还原

【Abstract】 Vacuum evaporation of metals was empirically approximated,mathematically modeled in gas molecule collision theory,theoretically analyzed and experimentally evaluated. The influence of the evaporation conditions,including but not limited to the pressure,temperature,density of residue gases,surface adsorption and desorption,on the evaporation rate of metal was investigated. When it comes to distillation of metal in low vacuum on industrial scale,the realistic collision between all molecules,including the residue gases in low vacuum and metal vapor at high temperature,considerably affects the saturated vapor pressure of metal,P0,in Langnuir formula,which was formulated by assuming an ultrahigh vacuum environment. The evaporation rates of Dy,Tb and Al were calculated with the modified Langmuir formula and experimentally measured,respectively. The calculated and measured results were found to be in fairly good agreement. We suggest that the modified Langmuir formula be of much technological interest in vacuum metallurgy of high purity rare-earth metals.更多还原