A method for simultaneously
removing sulfur dioxide (SO2) and nitrogen oxides (NOx)
from coke oven flue gas using steel slag
slurry was proposed. Due to the high removal efficiency of SO2, the effects of operation conditions on the removal of NOx
were investigated emphatically. The results showed that the removal
efficiency of NOx increased with an increase in steel slag slurry
concentration, NOx oxidation ratio, steel slag slurry pH, and NOx
and SO2 inlet concentrations and a decrease in reaction
temperature. The removal efficiencies of SO2 and NOx could
reach 100 and 83.4%, respectively, by optimizing the operation conditions.
The mechanism of NOx removal using steel slag slurry was investigated.
The results showed that (MgO)0.841·(MnO)0.159 (RO phase, a CaO–FeO–MnO–MgO solid solution)
in steel slag was decomposed by H+ and produced Mg2+ and Mn2+. Furthermore, Mn2+ in steel
slag slurry could promote the absorption of NO2 via redox
reactions with the generation of solid Mn3O4 and MnO(OH).