Simultaneous removal of SO2 and NOx from sintering flue gas using ammonia-Fe(II)EDTA combined with electrolytic regeneration

Sulfur dioxide and nitrogen oxide are health hazardous gases, which contribute to the formation of submicron acidic particulates. To reduce SO₂ and NO_x emission from the sintering flue gas, the combination of ammonia-Fe(II)EDTA solution scrubbing with Fe(III) electrolytic regeneration is proposed. The above method has the following advantages: direct conversion of NO_x and SO₂ to harmless N₂ and SO₄ ²⁻, recovery of the by-product (NH₄)₂SO₄), simultaneous removal of NO_x and SO₂ emission from flue gas in the reactor. The effect of the pH, initial Fe(II)EDTA concentration, and voltage on the desulfurization and denitration efficiencies was investigated using a bench-scale reactor. The maximal desulfurization and denitration efficiencies were 98% and 52%, respectively. The optimum parameters were pH ˃ 5.0, 2.1 V, and 0.05 mol·dm^–3 Fe(II)EDTA concentration. SO₂ and NO_x removal from the sintering flue gas by ammonia-Fe(II)EDTA solution scrubbing combined with electrolytic regeneration was also demonstrated in a pilot-scale reactor.