Generation and Inhibition of SO3 in Lead Smelting Flue Gas

The thermodynamic equilibrium of the gas-phase system in lead smelting flue gas was studied using FactSage 8.2 software, and the effects of temperature, the main components of the gas phase, and other factors on the SO3 content in the equilibrated flue gas were investigated. In addition, experimental research was conducted on a solid-phase catalysis experimental platform to investigate the effect of lead smelting ash on SO2 catalytic oxidation. The results show that temperature and initial O2 content in flue gas have a significant impact on the equilibrium concentration of SO3, while the initial SO2 content in flue gas has a relatively small impact on the equilibrium concentration of SO3; the fly ash from the lead smelting flue promotes the conversion of SO2 to SO3 in the flue gas. SO3-suppression experiments show that PbS can adequately inhibit SO3 formation in a simulated flue gas environment, and the content of SO3 after adding PbS under different oxygen contents and SO2 atmospheres does not exceed 0.6%. Through the method of thermodynamic simulation and experimental verification, this study reveals the catalytic oxidation mechanism of SO2 in lead dust and proposes the use of PbS as an in situ SO3 inhibitor.