Catalytic Effect of Cesium on the Oxidation Behavior of Cation Exchange Resins in Li 2 CO 3 -Na 2 CO 3 -K 2 CO 3 Melt

After the treatment of liquid radioactive waste, there is a certain amount of Cs in the waste resin, and these Cs-doped resins are prone to volatilize during the thermal treatment process and cause radionuclide leakage. The molten salt oxidation (MSO) can effectively prevent the volatilization of toxic metal, especially the volatilization of Cs. Under nitrogen and air conditions, it is found that the oxidation behavior between Cs-doped and clean cation exchange resins (CERs) is quite different. In the presence of oxygen and molten carbonate salt, Cs 2 CO 3 is generated by the destruction of functional groups in Cs-doped CERs. The Cs 2 CO 3 in Na 2 CO 3 -K 2 CO 3 -Li 2 CO 3 reacts with oxygen to form Li 2 O 2 , which reduces the content of S in residue from 26.33 to 13.38% in air conditions at 400 °C and promotes the generation of sulfate in the molten carbonate salt. The elements Cs and S in the Cs doped CERs spontaneously form thermally stable Cs 2 SO 4 in the molten carbonate salt.