Impurity distribution in metallic dysprosium during distillation purification

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• 作者：Xiaowei ZHANG (张小伟)^a ; ^{04202095@163.com" class="auth_mail" title="E-mail the corresponding author} ; Ruiying MIAO (苗睿瑛)^a ; Chuanjun LI (李传军)^b ; Daogao WU (吴道高)^a ; Huan YAN (闫 缓)^a ; Zhiqiang WANG (王志强)^a ; Dehong CHEN (陈德宏)^a ; Shihong YAN (颜世宏)^a ; Zongan LI (李宗安)^a
• 关键词：vacuum distillation purification ; distilled dysprosium ; impurity distribution ; modified separation coefficient ; rare earths
• 刊名：Journal of Rare Earths
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：34
• 期：9
• 页码：924-930
• 全文大小：988 K

文摘

The distribution rules of impurities contents in distilled metallic dysprosium were researched, and a theoretical analysis was carried out. The research results indicated that, the content of impurity in distilled metal, such as Al and Fe, was lower in the initial stage, increased slowly in the middle stage, and increased rapidly in the last stage during the process of distillation purification. The calculated method of separation coefficient of impurity in crude metal by content of impurity in distilled metal was not suitable for high pure metals, and the modified separation coefficient was proposed, and it equaled 1/6.1 and 1/16.9 for impurity Al and Fe. The physical process of distillation was coincident with that of solidification essentially, and solute re-distribution theory in solidifying front could be used to describe the impurity distribution near evaporating surface. In the former stage of distillation purification, the diffusion of impurity in liquid metal could reach a quasi-equilibrium state, the calculated result of impurity content in distilled metal agreed well with experiments. In the latter stage of distillation process, the diffusion rate of impurity in liquid metal decreased, and the content in distilled metal was larger than the calculated result.