China Nonferrous Metallurgy

Based on the characteristics of biochar containing more hydrogen， less carbon， more oxygen， and lower sulfur compared with traditional coal energy， this study investigates the thermal reduction mechanism of three types of biomass char-high iron red mud composite pellets， and compares the effects of three biomass chars on metallization rate， phase structure， micromorphology， and pore size. The following conclusions were drawn. Wheat bran char exhibits superior performance in enhancing the metallization rate and optimizing the phase structure of the composite pellets compared to the other two biomass chars. After thermal reduction at 1 100℃ for 2 h， the metallization rate reaches 86. 5%， which is 5. 2% higher than that of metallurgical coke and much higher than those of pine wood char composite pellets and corn char composite pellets under the same conditions. The main phase compositions of wheat bran char-high iron red mud composite pellets are metallic iron （44. 3%）， carbon （10. 6%）， gehlenite （Ca ?Al ? SiO?）， and nepheline （NaAlSiO?）， making them suitable for the vortex melting reduction ironmaking process. The wheat bran char-high iron red mud composite pellets possess a more uniform pore structure with a pore size of approximately 2-4 nm， a larger specific surface area， a better overall structure， a higher degree of surface metallization， and fewer residual impurities. The research results provide important reference for the efficient utilization of biomass resources.