High chromium vanadium-titanium magnetite all pellets 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. All pellets operation is one of the trends of blast furnaces to reduce CO₂ emission in the future. By referencing the production data of vanadium-titanium magnetite blast furnaces, this study explored the softening-melting (S-M) behavior of high chromium vanadium-titanium magnetite and obtained the optimal integrated burden based on flux pellets. The results showed that the burden composition of 70% flux pellets and 30% acid pellets obtained best S-M properties. In comparison with single burden, the S-M characteristic temperature of this burden composition was higher, the cohesive zone shifted downward and narrowed from 307 °C to 282 °C, the maximum pressure drop (ΔP_max) decreased from 26.76 kPa to 19.01 kPa, and the Permeability index (S) dropped from 4643.5 kPa·°C to 2446.8 kPa·°C. The S-M properties of integrated burden improved apparently. During the softening process, the acid pellets played a role in withstanding the load, and the flux pellets in the integrated burden during the melting process exhibited a higher slag melting point, which increased the melting temperature. The homogeneity of the slag and the TiC produced by the over-reduction led to the deterioration of the gas permeability of single burden. The segregation of acid and flux pellets in the HVTM proportion and basicity was the main reason for the better S-M properties of the integrated burden.