A novel electrochemical process for desulfurization in the CaO-SiO₂-Al₂O₃ system

The effect of electric potential on the sulfide capacity of the CaO-SiO₂-Al₂O₃ system was evaluated by applying voltages in the range of -1.5 to 1.5 V at 1823 K in a C/CO gas equilibrium. When the cathodic potential (-1.5 to 0 V) was applied, it was confirmed that the sulfur partition ratio increased based on the electrochemical reaction of sulfur (S + 2e^- = S^2-). However, the reversibility of the electrochemical resulfurization reaction (S^2- = S + 2e^-) in slag was not established in the reverse (anodic) potential region (0-1.5 V), yet the sulfur partition ratio increased. In particular, sulfur evaporation was observed in the anodic potential region. Therefore, in the present study, potential anodic electro-desulfurization mechanisms based on sulfur evaporation are proposed. To verify these mechanisms, sulfur evaporation is discussed in detail as a function of the thermodynamic stability of sulfur in the slag.