To efficiently and economically isolate and recover uranium from a nitric acid solution of a spent nuclear fuel, or, a waste or a waste liquid contain uranium.
The nitric acid solution containing uranium and plural elements is reduced using an electrolysis reduction method using a flow injection type electrolytic cell using a carbon fiber as a working electrode. The uranium exists as hexavalent uranium(U(VI))in the nitric acid solution before reduction. Tetravalent urnium(U(IV)) is generated when the U(VI) is reduced. The solution containing the U(IV) is thereafter brought into contact with an anion exchange member. One portion or all of the U(IV) in the solution is adsorbed onto the anion exchange member as a nitride ion complex by bringing the solution into contact with the anion exchange member. After the U(IV) is adsorbed onto the anion exchange member as the nitride ion complex by this manner, the adsorbed U(IV) is eluted from the exchange member to recover uranium, using a dilute nitric acid solution as an eluent.
I ETSUSHIYUU
KUMAGAI MIKIRO
TAKASHIMA YOICHI
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