The conventional thermal treatment of cation exchange resin substantially releases sulfurous gases, causing significant equipment corrosion and air pollution. In contrast, the Li2CO3-Na2CO3-K2CO3 as an alkaline molten system effectively neutralizes sulfur gas and mitigates waste gas production inherent in thermal oxidation methods. In the molten salt oxidation process, the volume concentration of SO2 was reduced by 81.7 % compared to that in the traditional thermal oxidation process, and this method reduces the generation of hazardous gases such as CO, CH4, and C2H6. The integration of online gas mass spectrometry and phase stability diagrams for carbonate and sulfur interception products demonstrate excellent thermodynamic stability during the molten salt oxidation (MSO) process. Moreover, a more accurate assessment of the acid gas neutralization capacity of the molten salt system is provided, and the acid gas neutralization capacity of the Li2CO3-Na2CO3-K2CO3 carbonate system can reach 82.58 % at 800 °C. The predominant contributors to acid gas neutralization are Na2CO3 and K2CO3, as evidenced by waste salt composition and ternary phase diagrams. The stable presence of Li2CO3 throughout the MSO process contributes to the lowering of the melting point of the carbonate system to 393 °C.