Effect of feeding amount on tail gas and waste salt obtained from molten salt oxidation process of cation exchange resins

The effective treatment of spent radioactive ion exchange resins generated during the operation of nuclear facilities is of great significance to reduce its potential hazards to the environment. This work innovatively provides a simple and low-cost molten salt oxidation (MSO) system includes air intake, feeding, waste salt discharge and exhaust gas treatment and analysis system for disposal of spent cation exchange resins (CERs). By studying three feeding amounts that injection of 25 g, 125 g and 1250 g CERs in 10 times under air conditions, the oxidation efficiency of CERs in MSO system was further evaluated. The scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) results indicated the sulfur can be trapped in the melt. Sulfur in functional group can be converted to Na2S and KLi(SO4) via Li2CO3-Na2CO3-K2CO3, which is proved by XRD patterns. The experimental results presented that degradation rates of CERs are 99.31%, 99.80%, and 99.91% in different feeding amounts, respectively. Furthermore, the volume reduction of residue gathered by feeding 1250 g CERs in 10 times was the highest, which can reach 9.19. Therefore, the bench-scale MSO system is a potential and promising treatment for spent CERs volume reduction.