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采用固态电迁移法对金属镨进行了提纯研究。在1×10~(-6)Pa真空环境下,分别在790,810和890℃下对工业纯电解镨进行固态电迁移处理85 h,对金属镨中主要杂质O,C,Fe,Cu,Al等元素含量进行测试,采用电感耦合等离子体质谱法(ICP-MS),辉光放电质谱法(GDMS),高频燃烧-红外法与惰气脉冲-红外热导法进行最终产品金属La的成分分析。结果表明:主要杂质O,C,Fe沿料棒向阳极迁移,Cu,Al向阴极迁移;镨的晶型转变对主要杂质O,C的迁移速率有很大影响,当电迁移温度超过镨的晶型转变点795℃,镨由dhcp结构转变为bcc结构后,表现为O,C在镨中的残余率迅速下降,且温度越高,O,C残余率越低。并以钙热还原制得金属镨为原料,经真空蒸馏提纯后,在890℃温度下进行电迁移处理216 h,在料棒阴极端区域B取样分析了78个杂质元素,金属镨纯度达到99.9929%,在国内首次制得绝对纯度高于4N的金属镨。
Solid state electrometallurgy was used to purify metal praseodymium. Under the vacuum atmosphere of 1 × 10 -6 Pa, the industrial pure electrolytic praseodymium was subjected to solid state electromigration for 85 h at 790, 810 and 890 ℃, respectively. The main impurities such as O, C, Fe, Cu and Al in the metal praseodymium Elemental content was tested and the composition of metal La in the final product was analyzed by inductively coupled plasma mass spectrometry (ICP-MS), glow discharge mass spectrometry (GDMS), high frequency combustion-infrared spectroscopy and inert gas pulse-infrared thermal conductivity . The results showed that the main impurities such as O, C and Fe migrated to the anode and Cu and Al migrated to the cathode along the material rod. The crystal transition of praseodymium had a great effect on the migration rate of major impurities O and C. When the electromigration temperature exceeded praseodymium The transition point of the crystal form is 795 ℃. After the praseodymium is changed from dhcp structure to bcc structure, the residual rate of O and C decreases rapidly in praseodymium, and the higher the temperature, the lower the O and C residual rate. Praseodymium as raw material was prepared by calcium thermal reduction. After vacuum distillation and purification, electromigration was carried out at 890 ℃ for 216 h, and 78 impurity elements were sampled and analyzed in the cathode end region B of the rod. The purity of the metal praseodymium reached 99.9929 %, The first time in China for the absolute purity of more than 4N metal praseodymium.