Influence of Al₂O₃/TiO₂/Na₂O on lime dissolution in steelmaking slag

A red mud-based flux containing Al₂O₃, TiO₂, and Na₂O constituents exhibits a pronounced flux-enhancing effect on traditional steelmaking slag systems. Therefore, the research on the dissolution mechanism of lime in steelmaking slag and the factors influencing its dissolution rate is significant in advancing the development of fluoride-free fluxes in steelmaking. In this experiment, the dissolution rate of lime in steelmaking slag containing Al₂O₃, TiO₂, and Na₂O was measured using the cylindrical rotation method, and analysis and demonstration of mineral phase changes during its melting process was conducted. The results indicates that the promotion coefficient for lime dissolution at 1 400 ℃ decreases in the order of Na₂O > TiO₂ > Al₂O₃, and adding 10 % Na₂O can increase the promotion coefficient for lime dissolution by a factor of seven. Furthermore, this paper explores the effects of Al₂O₃, TiO₂, and Na₂O on the diffusion of CaO in the slag and the lime decomposition reaction at the boundary layer, elucidating the dissolution mechanism of lime under these conditions. The concurrent presence of A1₂O₃/TiO₂/Na₂O in red mud-based flux has been identified as a suitable steelmaking flux.