In order to simultaneously achieve separation and volume reduction of radioactive cesium in the aqueous solution, we proposed a solvent extraction using a fluorinated solvent which is a nonflammable liquid having a low boiling point and is easy to distill for regeneration. Firstly optimum conditions for single extraction were determined in a batch operation. The extraction experiment was carried out by changing the pH of 5 mg/L non-radioactive cesium aqueous solution using bis(2-ethylhexyl)phosphoric acid (D2EHPA) as an extractant. The higher the pH of the aqueous phase and the D2EHPA concentration, the better the removal rate. The highest removal rate was about 60% under the pH=13. From the experimental results, the optimum extraction condition was determined as pH=13 and [D2EHPA]=0.15 mol/L. Next multiple extraction test was carried out under this condition, and 90% cesium removal could be achieved in 3 times extraction. Finally, the flow type device using a static mixer for mixing and extracting parts was proposed and then the cesium removal test was performed. The cesium removal performance of this device was equivalent to the batch system.
Development of Flow Type Cesium Removing Device Using Fluorinated Solvent