Method of electrolyzing and decontaminating by diaphragm electrolysis

Purpose: To continuously recover and remove radioactive metal ions reached out and accumulated in an electrolyte in the step of decontaminating the metal surface such as of equipments, parts or the likes contaminated with the deposition of radioactive materials through electropolishing. Method: The electrolytic vessel is partitioned by an electrolytic diaphragm into an anode chamber and a cathode chamber. The electrolyte in the anode chamber is recycled through a pump and a filter filtrates to collect suspended matters in the electrolyte. When a DC current is started to supply between the anode as the decontaminate and the anode as the collecting electrode, metal ions on the surface of the material to be decontaminated are leached in the anode chamber, while hydrogen gases evolve in the cathode chamber, by which the hydrogen ion concentration in the electrolyte is gradually reduced. Then, anions in the cathode chamber transfer through the diaphragm to the anode chamber and, conversely, the metal ions in the anode chamber transfer through the electrolytic diaphragm to the cathode chamber. Then, the pH of the electrolyte in the cathode chamber is settled to about 2 and metal ions starts to deposit at the chathode. (Horiuchi, T.)