Recent Advances in Elimination of SO₂ and NO_x from Flue Gas Employing Phosphorus Sludge and Phosphate Rock

Abstract

It is of great significance to achieve resource recycling while eliminating SO2 and NO x pollutants. Herein, the desulfurization and denitrification technology using phosphorus sludge and phosphate rock as absorbents has been attracting significant attention recently, owing to its low cost and pollution-free resource utilization. This paper timely reviews the removal performance, absorption mechanism, and reaction products of this technology, analyzes the dry and wet desulfurization characteristics of phosphate rock, emphasizes the key process of NO oxidation through the oxidative active substances induced by yellow phosphorus from phosphorus sludge, and summarizes the synergistic promotion mechanism of SO2 and NO x removal by the interaction between sulfur and nitrogen species. Furthermore, given current problems, this review points out the future research should focus on the mechanism of oxidative active substances excited by yellow phosphorus in water, the design of denitrification reactors, and the recovery of low concentration mixed acid after the reaction.