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本文研究镨、钕的络合物水溶液在汞阴极上的电沉积。实验证明,汞齐电极性质是决定镨、钕电沉积的可能性的条件,而络合剂种类对镨、钕的电沉积率有显著影响。镨、钕在季铵汞齐电极和在锂汞齐电极上都能形成汞齐,而在钠汞齐电极上则不能。镨、钕的电沉积率随汞齐电极变化的次序为钠汞齐<钾汞齐<<锂汞齐<季铵汞齐电极。这种次序与钠、钾、锂和季铵离子在滴汞电极上还原的析出电位次序一致,析出电位愈负,镨、钕在其汞齐电极上的电沉积愈有利。镨、钕的电沉积率随络合剂的变化,按柠檬酸>磺基水杨酸>>乙二胺四乙酸>乳酸的次序而递减。镨在柠檬酸溶液体系中可定量地进入汞相,钕的电沉率亦达97％左右。镨、钕在乳酸溶液体系中几乎不形成汞齐。镨、钕在磺基水杨酸中的电沉积率差别大,提供了分离的可能性。磺基水杨酸能直接溶解稀土元素的氧化物,只要稀土与磺基水杨酸的克离子比在1∶1.5以上即可。无论单稀土氧化物或混合稀土氧化物均能快速、完全地溶于磺基水杨酸中,使电解液制备方便,电解液组成简单,有利于稀土电沉积的研究。
In this paper, the electrodeposition of praseodymium and neodymium complexes on mercury cathodes was studied. Experiments show that the properties of amalgam electrodes are the conditions that determine the possibility of praseodymium and neodymium deposition, while the types of complexing agents have a significant impact on the deposition rate of praseodymium and neodymium. Praseodymium and neodymium can form amalgams on quaternary ammonium amalgam electrodes and on lithium amalgam electrodes, but not on sodium amalgam electrodes. Praseodymium, neodymium electrodeposition rate with the amalgam electrode changes in the order of sodium amalgam potassium amalgam lithium amalgam quaternary ammonium amalgam electrodes. This sequence is consistent with the order of precipitation potentials of sodium, potassium, lithium and quaternary ammonium ions on the drop mercury electrode. The more negative the precipitation potential, the more favorable the deposition of praseodymium and neodymium on the amalgam electrodes. The deposition rate of praseodymium and neodymium is decreasing with the order of citric acid> sulfosalicylic acid> ethylenediaminetetraacetic acid> lactic acid with the change of complexing agent. Praseodymium in the citric acid solution system can be quantitatively into the mercury phase, neodymium edema rate of about 97%. Praseodymium and neodymium hardly form amalgam in the lactic acid solution system. Praseodymium, neodymium in sulfosalicylic acid electrodeposition rate difference, providing the possibility of separation. Sulfosalicylic acid can directly dissolve rare earth oxide, as long as the rare earth and sulfosalicylic acid ion ratio of 1: 1.5 or more. Either single rare earth oxides or mixed rare earth oxides can be quickly and completely dissolved in sulfosalicylic acid to make the preparation of the electrolyte convenient and the composition of the electrolyte simple and conducive to the research of rare earth electrodeposition.