Effect of CaCl2 Addition on the Viscosity of CaO–SiO2–FeOx Steelmaking Slag System

In order to investigate the effect of CaCl2 addition on the viscosity of BOF steelmaking slag, a rotating viscometer was employed to measure the viscosities of different slags with different basicity and FeOx contents. Raman spectra were applied to understand the change of the microstructure of the CaO–SiO2–FeOx(–CaCl2) slag system, and the activation energy of the slag system was also considered to reveal the influential mechanism of CaCl2 on the slag viscosity. It was found that CaCl2 can effectively reduce the slag viscosity and the critical crystallization temperature (TCR). The rise of slag basicity can decrease the viscosity of the slag system at a high temperature (T > TCR), while it is not favorable to a lower viscosity when T < TCR. Due to the supply of free oxygen ions, both higher slag basicity and higher FeOx content can simplify the structure of silicates, no matter whether CaCl2 is added. Besides, a [FeO4]-tetrahedron peak is also found in the Raman spectra, but its variation is very small. Further investigation is still needed for the effect of FeOx on the microstructures of the slag system.