Pretreated water-quenched-manganese-slag slurry for high-efficiency one-step desulfurization and denitrification

Abstract Presently, researches on the use of low-cost pulp or slag for desulfurization and denitrification has attracted much attention globally. However, the efficiency of the NOx conversion remains low and has a short duration. Therefore, we tried to activate the water-quenched-manganese-slag (WQMS) through the pretreatment method of calcination and additive calcination then mixed with KMnO4 (oxidation and absorption in one step without pre-oxidation). The obtained removal efficiency of NOx and SO2 was high as 84.9% and 100% under optimal conditions. After adding the pre-treated WQMS, the absorption of NOx by the slurry increased to 228.65mg/L when denitrification rate was more than 65%, which is 3.6 times that of pure KMnO4. The increased denitrification efficiency after pre-processing was affected by the phase structure change of the WQMS, increased valence state of manganese, as well as the higher alkalinity of the WQMS. Furthermore, the mechanism of simultaneous desulfurization and denitrification was proposed. In summary, this study provided a new one-step strategy to simultaneously remove SO2 and NOx.