Electrochemical preparation of high purity actinide metals from aqueous solutions

海德、氧化物和碳化物经金属热还原，在熔盐中进行电解，得到了电阳离子。然而，用这些方法生产高放射性金属是一项巨大的任务。汞电极在水溶液中具有约-1.5V的大氢过电位，被广泛用于沉积属于通孔到IVb基团的元素，如铬、锰、铁、钴、镍、铜、锌、镓和锗，这些元素的还原电位比过电位更正。放射极谱是一种有趣的技术，其中水溶液中放射性离子的融合是通过水滴中的放射性来测量的，即使在比氢过电位更负的电位下也可以观察到波。这些事实表明，用汞池电极从水溶液中整体电解制备正极金属是可行的。研究了用汞池电极从水溶液中电化学制备铀、钚、镧和铈金属。铀的熔融速率近似为一级化学反应。另一方面，La和Ce的还原速率表现出与铀不同的动力学。通过气体和金属杂质分析，估计汞齐热分解制备的铀金属的纯度至少为4N。通过对金属镧和金属铈中汞的分析，确定了铍汞齐的加热温度。从醋酸盐缓冲溶液中合成了Ne汞齐，得到了金属Nb的光亮金属纽扣。研究结果表明，所提出的方法比传统的制备方法容易和简单得多，而且所制备的元素具有很好的品质。

Electropositive actinide metals have been prepared by metallothermic reduction of the haide, oxide and carbide and by electrolysis in a molten salt. It, however, is an enormous task to produce highly radioactive metals by these methods. The mercury electrode with a large hydrogen overpotential of ca. -1.5V in an aqueous solution is widely used to deposit elements belonging to the groups form VIa to IVb, such as Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga and Ge, whose reduction potentials are more positive than the overpotential. Radiopolarography is an interesting technique, in which the amalgamation of radioactive ions in aqueous solutions is measured by the radioactivity in the mercury drops and the waves are allowed to be observed even in the more negative potential than the hydrogen overpotential. These facts suggests the feasibility to prepare electropositive metals from the aqueous media by bulk electrolysis using a mercury pool electrode.The electrochemical preparation of uranium, neptunium, lanthanum and cerium metals from the aqueous solution using a mercury pool electrode was investigated. The amalgamation rate of uranium was approximately regarded as a first-order chemical reaction. On the other hand, the reduction rates of lanthanum and cerium showed a different kinetics from uranium. The purity of uranium metals prepared by thermal decompositions of the amalgams were estimated to be 4N at least by the gaseous and metallic impurity analysis. The heating temperature of the neptunium amalgams was decided by the analysis of mercury in the lanthanum and cerium metals. The neptunium amalgams were synthesized from acetate buffer solutions and the bright metallic buttons of neptunium metals were obtained. As a result of this study, and the proposed method is shown to be much easier and simpler than the conventional preparation and the actinide metals are found to be excellent quality.