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The influence of Cr2O3 and B2O3 on viscosities of CaO–SiO2–MgO–23.2 wt% Al2O3–TiO2‐based slags is studied by the rotating cylinder method in this work. Furthermore, the Raman spectra of the quenched slags are also investigated to obtain the structure information of slags with different Cr2O3 and B2O3 contents. From the viscosity experimental results, it is indicated that the viscosity increased with the addition of Cr2O3 and decreased with the addition of B2O3. The Raman spectra analyses reveal that Cr2O3 may exist as a network former and the polymerization degree of the slags increases with the rising content of Cr2O3. B2O3 also behaves as network formers in the present slag, which can increase the degree of polymerization and polymerize the network structure of the slags. The effect of network forming on visicosity is smaller than the effect of low melting point compound formations, which leads to the slag viscosity decrease with B2O3 addition.

The effects of TiO2 and FeO on the viscosities of CaO–MgO–Al2O3–SiO2–TiO2‐FeO slag are investigated by the rotating cylinder method. The structural characterization of the quenched samples are also studied by Fourier transform infra‐red and Raman spectroscopy. Experimental results show that viscosity decreases with increasing TiO2 or FeO, while keeping the basicity and contents of other components constant. Both, Fourier transform infra‐red and Raman spectroscopy results show that there are no significant change of the asymmetric stretching vibration bands for [AlO4] tetrahedra among the slags and there is no Q3 in the slags. It is concluded that both TiO2 and FeO in the slags behave as basic oxides, which break the silicate network in the slag and reduce the slag viscosity. The Raman spectroscopy results show that the Q2 in slag increases with increasing FeO and decreasing TiO2. The polymerization degree of silicates decreases with decreasing Ti–O–Si or Ti–O–Ti stretch vibration and increasing O–Ti–O or O–(Si, Ti)–O stretch vibration, which make the slag viscosity decrease.

The influence of TiO 2 on viscosities of CaO-SiO 2 -MgO-Al 2 O 3 -Cr 2 O 3 -based slags and the corrosion mechanism of carbon brick used in blast furnace hearth by slags was investigated in this work. From the viscosity experimental results, it was found that the viscosity decreased with the addition of TiO 2 . Furthermore, the critical temperature and activation energy for the viscous flow of slags also decreased with increasing content of TiO 2 . The corrosion of carbon brick depended on the component of the brick surface in contact to the molten slags. In the region consisting mainly of carbon, the corrosion of carbon brick may be caused by the oxidation of carbon and in lower carbon content area, the corrosion of brick was mainly caused by the dissolution and slag penetration.