Investigation of reduction behavior of various iron ores in a hydrogen-rich reducing atmosphere

The key to hydrogen-rich reduction technology in blast furnaces lies in the effective utilization of hydrogen-rich reducing gas. This study investigates the reduction behavior of various blast furnace charges (pellet, sinter, and lump) in hydrogen-rich reducing gas and analyzes how charge characteristics (such as pore structure and composition) influence the reduction behavior. The results indicate that, regardless of the type of iron ore, an increase in the H₂ percentage in the reducing gas (the H₂/CO ratio) significantly enhances the reduction rate under the same reduction time. High-grade charges favor the reduction process. For basicity (R) within the range of 0 to 0.25, an increase in R correlates with a decrease in the reduction degree and reduction rate index. Conversely, for Mg-Al ratio (M/A) within the range of 0.4 to 1.6, an increase in M/A corresponds to an increase in the reduction degree. SEM-EDS analysis of reduced samples shows that SiO₂ have minimal impact on the reduction process. The primary hindrance to reduction in pellets is the presence of large internal pores (>50 μm), which leads to significant carbon deposition on the surface. Smaller pore sizes and higher porosity in pellets are more favorable for reduction under hydrogen-rich conditions.