Hydrogen-rich reduction mechanism of basic pellets for low-carbon ironmaking

Hydrogen-enriched blast furnace ironmaking has emerged as one of the pivotal technologies for decarbonizing the integrated steelmaking route. To further investigate the hydrogen-rich reduction behavior of iron-bearing materials in blast furnaces, this study systematically examines the hydrogen-rich reduction reaction of basic pellets through interruption experiments combined with microstructural characterization and phase analysis. Experimental results demonstrate that the basic pellets achieved a 79.7% reduction degree in CO-N 2 atmosphere, which increased significantly to 93.7% with 16vol% H 2 , confirming hydrogen's remarkable enhancement effect on the reduction index of basic pellets. In the initial of reduction, CO accumulates on the surface of pellets, resulting metal iron on the surface, while the interior is the initial Fe 2 O 3 state. But hydrogen enhances the internal reduction degree. Hydrogen-rich promotes more thorough reduction of internal microparticles within basic pellets. XRD results indicate that in the later stage of CO reduction, the FeO peak of pellets is stronger. XRD fitting analysis demonstrate that FeO phase is 37.85% after 180min reduction, and the FeO phase of pellets reduced by reducing gas concluding 8vol% H 2 accounts for 14.79wt%.