An Efficient and Green Method for Flue Gas NO Removal by Steel Slag Flue Gas Desulfurization Tail Liquid

The tail liquid of steel slag flue gas desulfurization contains a large amount of FeSO4, which is potentially able to remove NO from flue gas by catalyzing the oxidation of H2O2. In this paper, desulfurization slurry with different sulfation degrees was obtained by controlling the reaction time of steel slag flue gas desulfurization, and then the slurry was further processed to acquire the catalyst containing FeSO4. Through the comparison of the catalytic performance of catalysts with different sulfation degrees, it was found that the catalyst with a sulfation degree of 70% had the best catalytic performance, and the removal rate of NO by catalytic oxidation of H2O2 could reach 90%. In addition, the long-term catalytic test proved that it possessed stable and efficient catalytic performance. The catalytic reaction time was prolonged due to the complex structure of the catalyst, and its efficient catalytic ability was also correlated to the desulfurization product FeSO4 attached to the silica gel surface with a high specific surface area. According to the calculation, 486.9 kg of the catalyst could be prepared per ton of steel slag flue gas desulfurization, showing low preparation cost and great application value.