Influence of desulfurization slag containing oxides of vanadium and titanium on semi-steel pre-desulfurization

The desulfurization and resulfurization of slag containing oxides of vanadium and titanium (CaO–SiO 2 –MgO–Al 2 O 3 –V 2 O 3 –TiO 2 –FeO) in the pretreatment of semi-steel desulfurization at 1623 K were investigated. Based on the ionic structure theory of slag, it could be concluded that V 2 O 3 and TiO 2 combined with (O 2– ) to form complex anions including VO_3^3- , TiO_4^4-, etc., which reduced the activity of (O 2– ) and decreased the sulfur partition ratio ( L S ). And FeO enhanced the activity of [O] at the slag–metal interface, which decreased the desulfurization capacity of the slag. Compared to the binary basicity, the presented basicity expression containing V 2 O 3 and TiO 2 described the relationship between L S and basicity more accurately. Considering the problems of dilute slag, a large amount of residual slag and much resulfurization in the slagging-off process after pretreatment, the effect of CaO + C-based slag modifier on the resulfurization, melting point and viscosity of the desulfurization slag was investigated. It was proposed that adding 5