High-chromium vanadium–titanium magnetite all-pellet integrated burden optimization and softening–melting behavior based on flux pellets

High-chromium vanadium–titanium magnetite (HVTM) is a crucial polymetallic-associated resource to be developed. The all-pellet operation is a blast furnace trend that aims to reduce carbon dioxide emissions in the future. By referencing the production data of vanadium–titanium magnetite blast furnaces, this study explored the softening–melting behavior of high-chromium vanadium–titanium magnetite and obtained the optimal integrated burden based on flux pellets. The results show that the burden with a composition of 70wt% flux pellets and 30wt% acid pellets exhibits the best softening–melting properties. In comparison to that of the single burden, the softening–melting characteristic temperature of this burden composition was higher. The melting interval first increased from 307 to 362°C and then decreased to 282°C. The maximum pressure drop (ΔP_max) decreased from 26.76 to 19.01 kPa. The permeability index (S) dropped from 4643.5 to 2446.8 kPa·°C. The softening–melting properties of the integrated burden were apparently improved. The acid pellets played a role in withstanding load during the softening process. The flux pellets in the integrated burden exhibited a higher slag melting point, which increased the melting temperature during the melting process. The slag homogeneity and the TiC produced by over-reduction led to the gas permeability deterioration of the single burden. The segregation of the flux and acid pellets in the HVTM proportion and basicity mainly led to the better softening–melting properties of the integrated burden.