Softening and melting behavior of iron ore-petcoke briquettes

Blast furnace efficiency is strongly influenced by the position and thickness of the cohesive zone, region of lowest permeability in the reator. This study investigates the softening and melting behavior of self-reducing briquettes composed of iron ore and petcoke (PC). Briquettes produced in a pilot plant with different levels of PC content, up to 15 wt%, were tested individually and in mixtures with high-basicity sinter. Softening and melting experiments, including interrupted tests, were conducted to assess the reduction behavior, permeability, and microstructural evolution. The results revealed that increasing the PC content in the briquettes led to a reduction in softening temperature and an increase in the thickness of the cohesive zone. However, the increase in PC content also promoted higher indirect reduction efficiency and significantly reduced carbon consumption. Mixed burden with 30 wt% briquette containing 10 wt% PC and 70 wt% sinter exhibited improved gas permeability in the cohesive zone and reduction efficiency. These findings confirm the metallurgical feasibility of integrating PC-based self-reducing briquettes into the blast furnace burden, offering a promising route to reduce fuel consumption and improve process sustainability.