Experimental Study on the Strength Distribution and Pore Distribution of Industrial Pellet and DRI

Against the backdrop of the “dual-carbon” goals driving the steel industry's transition toward hydrogen metallurgy, the hydrogen-based shaft furnace process has emerged as a focal point due to its low-carbon emissions. This study employs compression testing, mercury intrusion porosimeter, and industrial computed tomography characterization to compare the mechanical properties and pore structures of industrial pellets and direct reduced iron (DRI). The results show that the compressive strength and mass specific breakage energy of DRI are lower than those of pellets, and the breakage characteristic parameters at the same particle size are lower, making it more prone to breakage; the compressive strength of both increases with the increase of particle size, the mass specific breakage energy decreases with the increase of particle size, and the strength growth rate of pellets is faster. In terms of pore structure, pellets are mainly composed of uniform macropores of 3428 nm with a porosity of 22.3%; DRI has a porosity of 48.8%, mainly composed of 3431 nm macropores and 831 nm micropores, with a low tortuosity index, which is conducive to gas diffusion. This study provides parameters and theoretical basis for modeling of burden movement and crushing in shaft furnace.