Purification of yttrium metal by plasma arc melting

Abstract

Yttrium possesses unique physical-chemical properties and electronic structure, making high purity yttrium metal highly coveted for various applications. Nevertheless, the application of commercial yttrium metal is seriously restricted by the relatively low purity level. Considering the direct purification of commercial yttrium metal, plasma arc melting for decreasing impurity content is proposed. The purification of yttrium metal has been characterized and assessed by 68 impure elements. Experimental results show that plasma arc melting effectively removes impurities, resulting in an increase in the absolute purity of yttrium metal from 97.39 wt % to 99.10 wt %, with a reduction in the presence of 38 impure elements. The vapor pressure, metal separation factor, and mean free path of metallic impurities were calculated and categorized into high volatility, medial volatility, low volatility groups under the experimental conditions. Furthermore, plasma arc melting exhibits significant efficiency in removing nonmetallic impurities, and purification principle and migration mechanism are discussed in this work．The investigation of plasma arc melting proposes a new research direction for the preparation of high purity yttrium, and will promote the application of high purity yttrium in metal materials.