Viscous Behavior of FeO-Bearing Slag Melts Considering Structure of Slag

In the present study, an investigation on the viscosity of FeO-bearing slag, clarifies the effect of CaO/SiO₂ and FeO from an ionic structure perspective. The viscosity of FeO-bearing slag shows a complex dependence on CaO/SiO₂, with viscosity minima for CaO/SiO₂ = 1.3. It is suggested that the viscosity behavior is caused by the transition in the ionic structure of the slag from a melilite-like structure to a dicalcium-silicate-like structure. In addition, it is confirmed that FeO dissociates the silicate network structure in the melilite region and decreases the viscosity. In the dicalcium silicate region, however, viscosity decreases with increasing FeO owing to interference in the attraction between the calcium cation and the orthosilicate anion. Based on these experimental results and discussions, the relationship between the slag viscosity and ionic structure of the slag, and the influence of FeO on this relationship, are discussed in detail.