Estimation of Fluorine and Sulfur Behaviors Affected by Converter Off-Gas Dusts

Abstract

Converter steelmaking produces a large amount of high-temperature flue, which contains pollutant gases (SO₂, HF, etc.) and entrains fine dusts (Fe, FeO, Fe₂O₃, CaO, etc.), and fluorine and sulfur behaviors that were affected by dusts in off-gas are estimated by chemical equilibrium method. The behaviors of fluorine and sulfur in off-gas are very different at reducing and oxidizing atmospheres. At a reducing atmosphere, main fluorides in off-gas are SiF₄(g), CaF₂(s), HF, and CaF₂(g); the main sulfides are FeS₂(s), FeS(s), COS(g), SO₂(g), and S₂(g); and CaO can effectively defluorine at T < 1000 K. At oxidizing atmosphere, main fluorides are SiF₄(g), HF, and CaF₂(g); the main sulfides are Fe₂(SO₄)₃(s), CaSO₄(s), SO₂(g), and SO₃(g); and defluorination and desulfurization by dusts are completely effectively at MR ≥ 1 and T < 1100 K.

Keywords:

• Converter off-gas
• Dust
• HF
• SO₂

ACKNOWLEDGMENTS

Financial supports by the National Natural Science Foundation of China (No. 50976123) and the Knowledge Innovation Program of the Chinese Academy of Sciences (No. KGCX2-YW-321) are acknowledged.