Removal of SO₂ from flue gas using blast furnace dust as an adsorbent

To control the SO₂ emission and achieve the target of "waste controlled by waste", a novel desulfurization method with blast furnace dust slurry was proposed. The effects of reaction temperature, oxygen concentration, and solid-liquid ratio on SO₂ removal efficiency were investigated. The optimal conditions were reaction temperature of 35 ℃, oxygen concentration of 10 vol.%, and solid-liquid ratio of 0.5 g/300 mL. Under the optimal conditions, the desulfurization efficiency reached 100% for 4 h. Response surface methodology (RSM) results showed that oxygen concentration significantly influenced the SO₂ removal efficiency. Finally, the possible desulfurization mechanism of blast furnace dust was proposed based on the EDX, XRD, SEM-EDS, ICP, and IC. The blast furnace dust (main components are CaZn₈(SO₄)₂(OH)₁₂Cl₂·(H₂O)₉, Mn_6.927Si₆O₁₅·(OH)₈, ZnO, Fe₂O₃) reacted with H⁺ to form Zn²⁺, Fe³⁺, and Mn²⁺ which shows a key effect on the SO₂ liquid catalytic oxidation. This study provides a promising, feasible, and low-cost desulfurization technology by reusing blast furnace dust.