Temperature-dependent permeability of sinter and pellets under hydrogen-rich conditions for lumpy zone in the blast furnace

While increasing hydrogen share in the reducing gas represents an attractive path for reducing CO 2 ; emissions in blast furnace ironmaking, its effects on burden permeability remain poorly understood. This study systematically examines how hydrogen-enriched atmospheres affect the permeability of iron ore sinter and pellets across the lumpy zone temperature range (300–1100 °C). To isolate intrinsic hydrogen effects and establish performance boundaries, samples were reduced at three representative temperatures (500, 800, and 1000 °C) under pure gas compositions (100% CO, 60% CO-40% H 2 , and 100% H 2 ), followed by degradation and quantitative permeability analysis. Results show material-specific responses: Hydrogen improves sinter permeability by over an order of magnitude at 500 °C by suppressing carbon deposition, while pellets achieve optimal performance at 800 °C but deteriorate severely at 1000 °C under hydrogen-rich conditions. The middle lumpy zone (600–900 °C) emerges as the most favourable region for hydrogen injection, where both materials maintain adequate permeability while enabling CO 2 emission reductions. The study provides quantitative permeability parameters ( K , β) for computational modelling and strategic guidance for burden-specific hydrogen injection optimization, though alternative materials may exhibit different behaviours.