Hydrogen Impact on the Shrinkage Behavior Between Quaternary/Quinary-FeO-Rich Oxides

The issue of carbon emissions in the iron-making process is receiving increasing attention, and the utilization of hydrogen (H 2 )-reduced iron ore presents an appealing prospect for application. Iron oxides are the primary components involved in the iron-making process, and their reduction in H 2 holds significant research value. In this work, the softening–melting behaviors of quaternary/quinary-FeO-rich oxides in four different gases, namely 100%N 2 , 10%H 2  + 90%N 2 , 40%CO + 60%N 2 , and 10H 2  + 40%CO + 50%N 2 , above 900°C are studied by simulating the cohesive zone of blast furnace. Compared to CO, H 2 exhibits a higher reducing capacity and can achieve a faster reduction of metal iron. However, due to its inability to promote carburizing and further liquation of metal iron, iron remains in a dense metallic state within the packed bed, hindering its further reduction into iron oxide particles and consequently slowing down the shrinkage of the packed bed. Delaying the initial temperature of reaccelerated shrinkage to more than 1300°C also reduces the pressure drop within the packed bed. Its limited ability for liquid phase generation plays a positive role in influencing both the height contraction and permeability reduction of the packed bed. Furthermore, the formed spinel phase in H 2 with high melting point did not shrink until the temperature was increased to 1400°C, and a sudden increase in shrinkage rate (SR) to 0.12%/°C or above was observed. Graphical