论文部分内容阅读
研究了LiF-LaF3体系下,以La-Ni合金和La金属作可溶性阳极,以Ta为阴极,熔盐电解精炼镧过程中不同工艺条件对槽电压、沉积物形貌、产物杂质含量的影响。采用扫描电镜(SEM)对电解精炼所得La沉积物形貌进行观察,采用电感耦合等离子体质谱法(ICP-MS),辉光放电质谱法(GD-MS),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:槽压与电流之间的线性关系受到接触压降、熔盐性质等因素的影响,控制较高电解温度、使用La-Ni合金代替金属La作阳极时槽压较低;沉积物均为枝晶形貌,电流密度增大导致沉积物的形貌由三维多面体转变为二维片状,电解温度升高导致颗粒几何规则性减弱,低电流密度下沉积物生长机制应为阶梯状生长;金属杂质中W,Ta可由50~100μg·g-1降至2~3μg·g-1,使用La阳极的实验所得精炼产物金属镧纯度为99.867%(分析77个杂质元素)。
The effects of different process conditions, such as La-Ni alloy and La metal as soluble anode, Ta as cathode and molten salt for electrolytic refining of lanthanum on the cell voltage, the morphology of the deposit and the content of impurities in LiF-LaF3 system were investigated. Scanning electron microscopy (SEM) was used to observe the morphology of La deposit obtained by electrolytic refining. The surface morphology of La deposit was analyzed by inductively coupled plasma mass spectrometry (ICP-MS), glow discharge mass spectrometry (GD-MS), high frequency combustion-infrared Gas pulse - infrared thermal conductivity method for the final product composition analysis of metal La. The results show that the linear relationship between cell pressure and current is influenced by the contact pressure drop, the nature of molten salt and other factors, and the higher electrolysis temperature is controlled. When La-Ni alloy is used instead of metal La as anode, the cell pressure is lower. Dendritic morphology and current density lead to the change of the morphology of the deposit from three-dimensional polyhedron to two-dimensional sheet. The increase of the electrolysis temperature leads to the weakened regularity of the particles. The growth mechanism of sediment should be step-shaped growth under low current density . The W and Ta contents of metallic impurities decreased from 50-100μg · g-1 to 2-3μg · g-1. The purity of the obtained lanthanum was 99.867% (analysis of 77 impurity elements).