The effect of the addition of B₂O₃ and the CaO/Al₂O₃ ratios on the CaO–Al₂O₃–B₂O₃ melts’ structure was fully analyzed by molecular dynamics (MD) simulations. The results show that, with the increase in CaO/Al₂O₃ ratios, the charge compensation for [AlO₄]⁵⁻ tetrahedron changed from the oxygen tricluster structure to the charge provided by Ca²⁺, and the structure of [AlO₄]⁵⁻ tetrahedron was stabilized. The addition of B₂O₃ reduced the degree of polymerization of the aluminate melt, which, in turn, lowered the melt viscosity; in the systems with CaO/Al₂O₃ mole ratio less than 1, the added B₂O₃ mainly existed in the form of [BO₃]³⁻, which reduced the symmetry and the strength of the melt network structures; in the higher CaO/Al₂O₃ ratio systems, the depolymerization ability of the addition of B₂O₃ on aluminate network structures was enhanced with the increase in CaO/Al₂O₃ ratios, and the overall degree of polymerization of the melt decreased. The viscosity measurement shows that B₂O₃ lowers the viscosity of CaO–Al₂O₃ melts, which was consistent with the results predicted by MD simulations.

The effects of Ce₂O₃ and CaF₂ on the microstructure of silicate-based mold flux were investigated using an integrated approach combining molecular dynamics (MD) simulations with viscosity testing, SEM-EDS, and XRD analysis. The structural origin of changes in viscosity and crystallization behavior was revealed. It was found that the joint addition of CaF₂ and Ce₂O₃ to the silicate melt leads to a synergistic effect; CaF₂ acts as a diluent within the silicate network, while O²⁻ introduced by Ce₂O₃ promotes the depolymerization of the complex [SiO₄]⁴⁻ network. As a result, highly polymerized structural units (Q², Q³, and Q⁴) transform into less polymerized ones (Q⁰ and Q¹), reducing the overall degree of polymerization and enhancing slag fluidity. Moreover, the preferential formation of [SiO₄]⁴⁻–Ce³⁺–F⁻ and [SiO₄]⁴⁻–Ca²⁺–F⁻ coordination structures replaces the original [SiO₄]⁴⁻–Ce³⁺ and [SiO₄]⁴⁻–Ca²⁺ linkages. This structural rearrangement facilitates the formation of low-melting-point phases during cooling, thereby suppressing the crystallization tendency and improving the stability of viscous properties of the mold flux. These findings provide theoretical insight for the design of high-performance fluxes used in rare earth-containing steel continuous casting.

Blast furnace (BF) ironmaking is a complex multiphase process involving gas–solid flow, heat transfer, chemical reactions, burden movement, and phase transformation under high-temperature conditions. Since many internal states of the blast furnace cannot be directly observed during operation, numerical simulation and mathematical modeling have become important tools for understanding furnace behavior and optimizing operational parameters. This paper reviews recent advances in blast furnace numerical simulation and internal state reconstruction methods. Existing approaches, including packed-bed flow models, cohesive zone reconstruction methods, burden distribution models, and temperature field prediction methods, are summarized and discussed. In addition, the evolution of blast furnace mathematical models from early one-dimensional steady-state formulations to modern three-dimensional multifluid and hybrid simulation approaches is reviewed. Recent developments in computational fluid dynamics (CFD), the discrete element method (DEM), digital twin, and data-driven modeling are also discussed. Compared with traditional simplified models, modern multidimensional and hybrid approaches show improved capability in describing asymmetric furnace inner states, multiphase transport behavior, and operational parameter effects under industrial conditions. However, challenges still remain in achieving computational efficiency, parameter calibration, multiphase coupling, and real-time industrial application. Future studies are expected to focus on the integration of mechanism-based simulation and intelligent data-driven methods to improve prediction accuracy, operational adaptability, and intelligent control capability in blast furnace ironmaking.