| 摘要 |
<p>PURPOSE:To make it possible to recover valuable metal contained in nitric acid-dissolved liquid effectively by performing electrolysis of the nitric acid dissolving spent nuclear fuel with a constant voltage, depositing platinum-group elements and silver on a negative electrode, and polarizing the negative electrode into the anode. CONSTITUTION:Nitric acid-dissolved liquid is once stored in a tank 1. Then, the liquid is guided into an electrolytic cell 10 and undergoes reduction electrolysis (e) with a potentiostat 11. Thus, valuable metal is deposited (d) on an electrode. The processing liquid, which flows out of the cell 10, is sent into a tank 12, and the composition of the liquid is measured. Nitric acid solution is supplied from a nitric acid tank 2 into an electrolytic cell 20, wherein the specified reduction electrolysis is finished. Oxidizing electrolysis (f) is performed with a potentiostat 21. The nitric acid solution after desorption (g) is sent into a tank 22, and the composition of the liquid is measured. After the procedures have been performed in the cells 10 and 20 for a specified time, the nitric acid-dissolved liquid from the tank 1 is supplied into the 20, and the nitric acid solution from the tank 2 is supplied into the cell 10. The reverse procedures are performed, respectively. Then, the procedures are repeated in each cell. The nitric acid solution, from which the valuable metal is recovered, is recovered and recycled to the tank 2.</p> |
