Effect of Basicity and Hydrogen-Rich Atmosphere on the Softening-Melting Behavior of Vanadium-Titanium Magnetite Pellets

Vanadium-titanium magnetite (VTM) is a polymetallic mineral resource containing Fe, V, and Ti, which has rich application prospects and great economic value. In modern ferrous metallurgy procedures, the blast furnace method with a burden composition of high-basicity sinter, acid pellets, and lump ore is still used for VTM smelting. Due to the excellent performance of pellets in terms of energy consumption and emissions, high-percentage pellets and all pellet smelting technology are in line with the development direction of the steel industry in the context of “carbon peak and neutrality”. The results showed that when the basicity of VTM pellets increased from 0.08 to 1.3, the softening interval (ΔT₁) decreased from 114 °C to 97 °C, the melting interval (ΔT₂) decreased from 180 °C to 173 °C and then increased to 194 °C, and the permeability index (S) increased from 831.44 kPa °C to 2034.68 kPa °C. As the basicity increased, the softening and air permeability properties gradually deteriorated, and the melting properties first improved and then deteriorated, and finally the softening-melting properties were optimal at a basicity of 0.5. When the H₂ content increased from 0 to 15pct, ΔT₁ increased from 113 °C to 145 °C, ΔT₂ decreased from 173 °C to 141 °C, and the S-value increased from 885.62 kPa °C to 914.34 kPa °C and then decreased to 585.56 kPa °C. As the H₂ content increased, the softening zone of the VTM pellets became wider, while the melting zone stuck narrower and the air permeability of the burden increased. Therefore, replacing CO with H₂ improved the softening-melting performance of VTM pellets.