Distribution coefficient of some metallic elements between nitric acid and anion exchange resin were measured. From the results described above, the fundamental data on the separation of each element in nitric acid were obtained.

Uranium, protactinium and thorium are satisfactorily separated from each other by secondary amine extraction. Amberlite LA–1 in kerosene diluent is used as the extractant. Separation from hydrochloric acid solution is superior to that from systems using other acids. The acid dependency of the extraction coefficient by anion exchange resin, but the former has selectivity for uranium. Under the total dose of 5×107r., the radiation damage of Amberlite LA–1 is negligibly small. From these results, it is evident that there is a possibility of applying the amine extraction to the recovery of uranium-233 from reactor blanket fuel.

The amine extraction of rare earth elements in nitric acid is compared with anion exchange and TBP extraction with respect to the increase or decrease in Kd value with increasing atomic number of rare earth elements. Concerning the relationship between distribution coefficient and atomic number of rare earth element, a similar trend is observed in anion exchange and amine extraction. The distribution coefficient decreases with increase in the atomic number. In TBP extraction, however, the corresponding value increases with increasing atomic number. It seems that the mechanism of amine extraction for rare earth element is similar to that of anion exchange.

No abstract

The effect of radioactivity on the radiocolloid formation of europium has been described. The centrifugal behavior of radioactive and of nonradioactive europium has been compared as a function of the of the solution at extremely low europium concentrations. The concentration of nonradioactive europium was determined by radioactivation analysis. No difference could be observed between the behavior of radioactive and of nonradioactive europium. The effects of the europium concentration and of other electrolytes have also been studied. Radioactivity does not seem to play an essential role in the radiocolloid formation of europium. Zusammenfassung Es wurde der Effekt der Radioaktivität auf die Formation von radiokolloidalem Europium beschrieben. Das zentrifugale Verhalten von radioaktivem und nichtaktivem Europium wurde verglichen als Funktion des PH-Wertes der Lösung bei extrem kleinen Europiumkonzentrationen. Die Konzentration des inaktiven Europiums wurde mit Hilfe der Radioaktivierungsanalyse bestimmt. Es konnte kein Unterschied zwischen radioaktivem und nichtaktivem Europium beobachtet werden. Außerdem wurden die Effekte der Europiumkonzentration und der Konzentration anderer Elektrolyte studiert. Die Radioaktivität scheint bei der Formation von radiokolloidalem Europium keine wesentliche Rolle zu spielen. RésuméOn décrit l'effet de la radioactivité sur la formation de radiocolloïde d'europium. On a comparé le comportement lors de la centrifugation d'europium actif et non actif en fonction du pa pour des solutions de concentration extrêmement faible. La concentration de l'europium inactif a été déterminée à l'aide d'analyses par activation. Il n'a pas été possible d'observer une différence entre le comportement de l'europium radioactif et inactif. Les effets de la concentration de l'europium et d'autres électrolytes ont été également étudiés. Il semble que la radioactivité ne joue pas un rôle essentiel dans la formation de l'europium radiocolloïdal.