Purification of yttrium to 4N5+ purity

• The average distillation rate of Y was found to be ∼2.144 × 10−4 g cm−2 s−1 at the distillation temperature of 1800 °C.
• The relation between the contents of non-metallic impurities and atomic voids was studied.
• Detailed evaluation of overall purity of yttrium was analysed by GDMS and IGA.

Purification of yttrium by vacuum distillation was carried out and the purification process of yttrium was studied. More than 60 metallic impurity elements of input as well as purified Y were analysed using glow discharge mass spectrometry (GDMS) and C, N, O, and S were analysed by interstitial gas analysis (IGA). The analysis confirmed the reduction of total impurity content from <10,202.96 ppmw to <27.45 ppmw. High volatile impurities such as Mg, Ca, Ti, Mn, Zn, Dy, Ho Er and Tm were reduced effectively after the first step carried out at ∼1600 °C for 4–6 h. The crucible impurity W and Ta was drastically reduced in the distilled yttrium at a distillation temperature of ∼1800 °C under a dynamic vacuum of ∼1.5 × 10−4 Pa; meanwhile, C, N, O, and S were decreased to low content, in which O was 75 ppmw. The evaporation rate and mean free path were calculated under the experimental conditions in this paper.