To provide a method for separating actinoid elements from rare earth elements which has high separating efficiency (coefficient of separation) without requiring a strict concentration control, can easily fractionate the actinoid element in post-treatment, and causes no waste difficulty to dispose.
In a group separating method for separating a high level waste solution every element group, an aqueous solution 3 containing hydrazine carbonate is mixed as a reverse extract, to a solvent 6 to be treated which contains actinoid elements and rare earth elements to separate the mixture into water phase and organic phase, and actinoid elements are recovered from the water phase. The concentration of hydrazine carbonate is set within a range where the distribution ration of auctionid elements is smaller than 1, and the distribution ratio of rate earth elements is larger than 1, preferably within a range of about 0.9 mole/L or more and about 2.0 mole/L or less.
ARAI KAZUHIRO
KUBOTA MASUMITSU
SHIROHASHI KOICHI
JAPAN ATOMIC ENERGY RES INST
Next Patent: REACTOR IRRADIATION SAMPLE SEALED VESSEL