Simultaneous removal of SO2 and NO using a novel method with red mud as absorbent combined with O3 oxidation

Bin Li; Heng Wu; Xiaolong Liu; Tingyu Zhu; Fagao Liu; Xingting Zhao

doi:10.1016/j.jhazmat.2020.122270

Simultaneous removal of SO₂ and NO using a novel method with red mud as absorbent combined with O₃ oxidation

J Hazard Mater. 2020 Jun 15:392:122270. doi: 10.1016/j.jhazmat.2020.122270. Epub 2020 Feb 11.

Authors

Bin Li¹, Heng Wu², Xiaolong Liu³, Tingyu Zhu⁴, Fagao Liu⁵, Xingting Zhao¹

Affiliations

¹ Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, China.
² Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming, 650500, China; Beijing Engineering Research Center of Process Pollution Control, National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China.
³ Beijing Engineering Research Center of Process Pollution Control, National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China. Electronic address: liuxl@ipe.ac.cn.
⁴ Beijing Engineering Research Center of Process Pollution Control, National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China; Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China. Electronic address: tyzhu@ipe.ac.cn.
⁵ Beijing Engineering Research Center of Process Pollution Control, National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China.

PMID: 32086090
DOI: 10.1016/j.jhazmat.2020.122270

Abstract

Aiming at SO₂ and NO_x in industrial flue gas, the simultaneous removal of SO₂ and NO_x was conducted using red mud as absorbent with O₃ oxidation. The effects of different factors on the desulfurization and denitration efficiency were investigated. The results show that the increase of oxidation temperature is not conducive to the absorption of NO_x (O₃/NO molar ratio >1). Low concentration of SO₂ promotes the absorption of NO_x, however high concentration of SO₂ inhibits absorption of NO_x. The main product after desulfurization and denitration of red mud solid residue is bassanite (CaSO₄·0.5H₂O). In addition, when the pH is greater than 5, calcium carbonate and sodium alkali play major roles in red mud, and when 3.5< pH < 5, sodium aluminosilicate hydrate (1.08Na₂O·Al₂O₃·1.68SiO₂·1.8H₂O), calcium nepheline (Na₆CaAl₆Si₆(CO₃)O₂₄·2H₂O) and garnet (Ca₃Al₂(SiO₄)(OH)₈) take part in the reaction. According to typically practical conditions with oxidation temperature at 130 °C and the O₃/NO molar ratio being 1.8, the desulfurization efficiency of red mud can reach 93 % in the first hour, and the denitration efficiency can be maintained at about 87 %. Besides, the reaction mechanism with multi oxidation absorption steps was also proposed.

Keywords: Desulfurization and denitration; O(3)oxidation; Reaction mechanism; Red mud; Simultaneous removal.

Publication types

Research Support, Non-U.S. Gov't