Thousands of radioactive mixed resins (MR) generated from nuclear industry can be processed by molten salt oxidation. There are three stages during the MSO process of MR: (1) the evaporation process (25-200 ℃); the thermal decomposition of the functional groups (200-450 ℃); (3) the depolymerization of styrene-divinylbenzene (450-800 ℃). Moreover

the thermal decomposition of the functional groups can be further divided into the thermal decomposition of the quaternary ammonium group (200-300 ℃) and the spitting off of the sulfonic acid group (300-450 ℃). NO and SO

2

respectively

were produced by the destruction of these functional groups. The carbonate salt can effectively adsorb NO and SO

2

whose contents decrease from 17.72% to 3.32% to 2.08% and 1.45%. Moreover

the sulfate contents in molten salt can be promoted by the generation of nitrate

which increase from 12.87% to 25.44% at 500 ℃. The change of the standard Gibbs free energy (Δ

G

m

θ

) of the reactions about the generations of nitrate and sulfur species

and the reactions between the nitrate and sulfur species were also proved by the calculation results of HSC chemistry 6.0. Both experimental and calculated results support the finding that the generation of nitrate from MR can catalyze the further oxidation of residue.