Effect of Substituting CaO with BaO on Viscosity and Structure of CaO–SiO2–FeOt–Al2O3–BaO Steel Slag

The viscosity of CaO–SiO₂–FeO_t–Al₂O₃–BaO steel slag with the BaO substitution for CaO is measured. Calculation of the corrected optical basicity and the apparent activation energy of the steel slag are executed. The effect of substituting CaO with BaO on structure evolution is studied. The measured results show that the viscosity of molten slag increases with the BaO substitution. The values of corrected optical basicity decrease from 0.63441 to 0.62329 with the BaO substitution. The apparent activation energy shows an upward trend from 152.78 to 160.62 kJ mol⁻¹ with the BaO substitution. The Fourier transform infrared reflection analysis indicates that the structure complexity of the [SiO₄] and [AlO₄] tetrahedrons is increased with the BaO substitution. The Raman analysis indicates that the translation of Q⁰ and Q¹ to Q² and Q³ is advanced with the substitution of BaO for CaO in molten slag. The conversion of O²⁻ to O⁰ is promoted with the substitution of BaO for CaO using X-Ray photoelectron spectrometer analysis. The complexity of the molten slag network structure and the degree of polymerization are all increased by the substitution of BaO for CaO, which sits comfortably with measured viscosity results.