Study on the destruction process of cationic exchange resins treated by Li2CO3-Na2CO3-K2CO3 molten salt

Abstract

With the continuous development of the nuclear industry, there is an urgent need to find a method that can safely and efficiently dispose of spent resins. Molten salt oxidation (MSO) is a promising waste treatment technology. In this paper, the newly shipped resins were used to simulate the actual spent ion exchange resins. The destruction of the resins is mainly divided into three stages. The addition of oxygen can increase the activation energy (E) required for the reaction. Some solid residues which were proved to be amorphous carbon materials generated after MSO. In the high-resolution XPS spectra of C 1s, the C-S bond disappeared after MSO at 400 ℃ for 2 h proved the destruction of the sulfonic acid groups. The core-level scan XPS spectra of S 2p illustrated that sulfur and sulfonyl bridges were formed after sulfonic acid groups were destroyed. The infrared spectrum also showed that the sulfonic acid groups were destroyed at 400 ℃ to form sulfonyl structure, but sulfur bridges were not found due to its small IR absorptions. In this paper, the ternary eutectic Li2CO3-Na2CO3-K2CO3, can be operated efficiently at a relatively low temperature. The generated sulfur dioxide is captured by the carbonate to form sulfate. These merits make MSO become a promising and environmentally friendly approach for the treatment of sulfur-containing organic waste.