In low reducing agents operation of blast furnace, it is considered that deadman gas permeability would become low due to fines accumulation around or in the deadman, which would cause unstable behavior of solid and gas. For the stable operation, especially in high productivity operation, the problem must be overcome. A scale-down three-dimensional cold model of blast furnace with a device capable of changing deadman physical properties such as the permeability and height, was used for this study. The effect of gas flow rate/velocity and deadman properties on both the unstable/discontinuous behavior and the solid flow pattern, is analyzed experimentally. In such a situation that gas is impossible to penetrate from the raceway inside the deadman and further bridging is formed over funnel flow channel in Bosh to Belly region, the discontinuity increased with increasing of gas flow rate and gas velocity. The more the gas impermeable wall is high, the more the discontinuity with bridging becomes severe. If the gas impermeable wall height is lower or deadman gas permeability is well, the discontinuity decreases, the solid bed becomes more homogeneous with dense packing state and solid plug flow region enlarges in the lower part. As a result, maintaining gas permeability of deadman in a good state and controlling deadman height lower might be essential for the stable operation.
