高纯稀土金属Sm、Yb和Tm的制备

采用镧热还原蒸馏法对蒸气压较高的稀土元素Sm、Yb和Tm的制备进行了研究，制得了纯度达4N级的稀土金属Sm和Yb，其纯度分别为99.99%和99.993%（质量分数，相对75种杂质元素）；对于稀土金属Tm，由于还原温度较高，还原蒸馏产物中La的含量偏高，需要对其进行低温、高真空升华提纯，提纯后纯度达到99.995%（同上）；实验结果表明，高纯度还原剂La的制备，尤其是La中金属杂质总量的控制，是获得4N级Sm、Yb和Tm的关键步骤。

Preparation of high purity rare earth metals of samarium, ytterbium and thulium

High purity rare earth metals, such as samarium, ytterbium and thulium, have been prepared by vacuum reduction-distillation of each rare earth oxide with lanthanum metal. The rare earth metals of samarium and ytterbium with 4N-purity are prepared by direct vacuum reduction-distillation, and the purity of above metals is 99.99 wt.% and 99.993 wt.% respectively with respect to 75 impurities; there is a high concentration of reductant in thulium metal due to the higher reaction temperature and lower distillation velocity ratio of metallic thulium to lanthanum, so that the sublimation purification with lower temperature and high vacuum has been conducted, the purified thulium can be reach a high purity of 99.995 wt.% with respect to 75 impurities; the experimental results indicates that, the preparation of high purity reductant of lanthanum metal, especially of total amount control of metallic impurities, is the key step to obtain 4N-purity rare earth metallic samarium, ytterbium and thulium.