Increasing Lump Ores Proportion in Blast Furnace Based on the High-temperature Interactivity of Iron Bearing Materials

Abstract

In this work, the feasibility of increasing lump ores proportion in blast furnace (BF for short) was investigated. The results showed: (1) Not only the physical and chemical properties, but also the metallurgical properties of lump ores, such as the reducibility, thermal decrepitation properties and softening properties, were not worse than those of the pellets, so the BF production would not be influenced greatly when the pellets were replaced by lump ores. (2) The own softening and melting properties of the lump ores (pellets) were dramatically improved by interaction between sinters and lump ores (pellets) found in the experiments, while there was no obvious interaction between lump ores and pellets, pellets and pellets, lump ores and lump ores. The interaction occurred with the contact of burden as in BF, and the main reaction product was CaFeSiO₄. Except temperature, the reaction was influenced by the chemical composition, micro-structure and contact conditions, and so on. (3) The softening and melting properties of the integrated furnace charge were improved, and the high-temperature interactivity of iron bearing materials was enhanced when the proportion of lump ores increased and the proportion of pellets decreased, for the reactivity of the lump ore was stronger than that of the pellets. (4) Furthermore, the collocation pattern of lump ores and ratio between lump ores was optimized according to interaction. When the proportion of lump ores was up to 23% at the excellent collocation pattern and appropriate ratio, the burdens still conformed to the requirements of ironmaking.