Effect of TiO2and BaO on viscosity and potassium removal capacity of blast furnace slag

In order to increase the utilization rate of vanadium–titanium magnetite in blast furnace smelting, the viscosity and potassium removal capacity of CaO–SiO2–Al2O3–MgO–BaO–TiO2slag (CaO/SiO2= 1.05, 1–5 wt.% BaO, 2–20 wt.% TiO2) were studied for slag optimization using the cylinder method and slag–metal equilibrium technique, respectively. Also, the structural properties of the slag were characterized by Fourier transform infrared spectroscopy. The concept of “a ring structure of Ti–O–Si” was proposed to express the change in the viscosity of the blast furnace slag. The results showed that the viscosity of slag increased with the increase in BaO content while the potassium removal capacity decreased. Furthermore, an increase in TiO2content from 2 to 20 wt.% resulted in a decrease in viscosity and an increase in potassium removal capacity. The Fourier transform infrared spectroscopy results showed that the charge compensation of Ba2+can form complex aluminosilicate structure and increase the viscosity of slag. Meanwhile, with the increase in TiO2content, Ti4+ions replace Si4+in the silicon-oxygen tetrahedral structure, thereby reducing the degree of polymerization of the silicate network and decreasing the viscosity.