Removal of SO2 from flue gas using blast furnace dust as an adsorbent.

To control the SO2 emission and achieve the target of "waste controlled by waste", a novel desulfurization method with blast furnace dust slurry was proposed. The effects of reaction temperature, oxygen concentration, and solid-liquid ratio on SO2 removal efficiency were investigated. The optimal conditions were reaction temperature of 35 ℃, oxygen concentration of 10 vol.%, and solid-liquid ratio of 0.5 g/300 mL. Under the optimal conditions, the desulfurization efficiency reached 100% for 4 h. Response surface methodology (RSM) results showed that oxygen concentration significantly influenced the SO2 removal efficiency. Finally, the possible desulfurization mechanism of blast furnace dust was proposed based on the EDX, XRD, SEM-EDS, ICP, and IC. The blast furnace dust (main components are CaZn8(SO4)2(OH)12Cl2·(H2O)9, Mn6.927Si6O15·(OH)8, ZnO, Fe2O3) reacted with H+ to form Zn2+, Fe3+, and Mn2+ which shows a key effect on the SO2 liquid catalytic oxidation. This study provides a promising, feasible, and low-cost desulfurization technology by reusing blast furnace dust.