Reduction, Softening, and Melting Characteristics of Mill Scale‐Based Briquettes for Blast Furnace Ironmaking

This study investigates the cold‐ and high‐temperature properties of mill scale‐based briquettes, with particular focus on their reduction, softening, and melting behaviors. The agglomerates exhibit shatter strength within industrial standards and low decrepitation. Nonisothermal reduction experiments indicate that the mass loss of the briquettes is associated with moisture evaporation, binder decomposition, and iron oxide reduction, with the lowest compressive strength observed at 800 °C. X‐ray diffraction and scanning electron microscopy analyses allow monitoring of the reduction progress, revealing a low reacted fraction and reduction degree at 1100 °C. The softening and melting parameters of the briquettes are comparable to those of high‐performance iron‐bearing materials widely used in the industry, displaying an intermediate softening interval and relatively wide melting interval, but demonstrating gas permeability comparable to sinter and better than acid pellets. The reduction behavior follows a three‐stage mechanism, with a significant retardation observed in region two. The transition from region one to two occurs at 1050 °C, earlier than the other materials tested, limiting overall reduction degree (47%). Briquettes’ carbon consumption due to direct reduction is close to that of lump ore and higher than that of pellets and sinter. From this perspective, briquettes can potentially substitute conventional acidic materials in blast furnaces.