Production of SO2 Gas: New and Efficient Utilization of Flue Gas Desulfurization Gypsum and Pyrite Resources

To effectively solve the problem of recovery and utilization of flue gas desulfurized gypsum (FGDG) , a new method for preparing SO2 gas by adding a mixture of FGDG and pyrite into a boiling furnace and utilizing its high-temperature waste heat is proposed. Using the FactSage 6.1 Reaction module and the Equilib module, the pyrolysis behavior of FGDG with pyrite and the release characteristics of SO2 gas were studied. The effects of FeS2 addition, temperature, and ventilation flow rate on the decomposition of FGDG and the change in gas behavior were studied by thermogravimetric mass spectrometry and settling furnace (SF) experiments. In addition, the activation energies of the chemical reactions were determined by the Kissinger method, the Kissinger–Akahira–Sunose method, and the Flynn–Wall–Ozawa method. The results show that between 100°C and 200°C, mainly the loss process of CaSO4•2H2O crystal water from FGDG occurred. At 570°C, FeS2 primarily undergoes self-decomposition. Between 820°C and 1000°C, the d...