Viscosity prediction on iron-bearing slags during pyrometallurgical recycling: structure-based modeling of CaO−‘FeO’−MgO−Al₂O₃−SiO₂ system and its subsystems

A structure-based modeling of the CaO−‘FeO’−MgO−Al₂O₃−SiO₂ system and its subsystems was investigated based on iron extraction from nickel slag by aluminum dross. Parameters optimization in the present model indicated that the coefficient of free O²⁻ in FeO, \(a_{{{\text{O}}_{{{\text{FeO}}}}^{{2 - }} }}\), on the lengths of network linkage had the largest value and \({\text{O}}_{{{\text{FeO}}}}^{{2 - }}\) (free O²⁻ in FeO) had the largest mobility. The coefficients of bridging oxygen (a_Si−O−Al and a_Al−O−Al) were lower than those of non-bridging oxygen and free oxygen (O²⁻). Viscosity prediction for the CaO−‘FeO’−(8 wt.%) MgO−Al₂O₃−SiO₂ system was conducted at a fixed slag basicity, which indicated that the predicted viscosity changed monotonously with the FeO content. However, the non-monotonous evolution with Al₂O₃ content reflected the amphoteric behavior of Al₂O₃. In addition, the performances of the present model in predicting viscosity from binary (‘FeO’−SiO₂) to quinary (CaO−‘FeO’−MgO−Al₂O₃−SiO₂) system were analyzed and a comparison with the established models was made.