Properties of core ore in quasi-particle required for large amounts usage of limonitic ores in iron ore sintering process

Abstract

The fluidity of melt formed in the sintering process of iron ores is an important factor for producing a high-strength sinter. When using a large amount usage of limonitic ores as core ore of the quasi-particle of sinter mix, it is predicted that the fluidity of formed melt decreases, because the solid ratio in the melt increases by an acceleration of the assimilation of the core ore with the melt. In order to control the assimilation of limonitic ore, basic researches were conducted using a modeled briquette, which consisted of a disk-shaped iron ore core and a shell layer of fine mixture composed of Fe 2O3 and CaCO3 reagents. Assimilation rate of various iron ores was measured, and then solid phase ratio in the melt was calculated based on the phase diagram of CaO-Fe2O3 system. According to the calculated solid phase ratio in the melt, the fluidity of melt was discussed. The results obtained are summarized as follows: Fair linear relations were obtained between the porosity of core ore after dehydration and the combined water content of the ore. The assimilation rate of core ore at a specified temperature was represented as a function of the porosity of core ore after dehydration and the holding time at the temperature. The diameter and the apparent density of core ore influenced the calculated solid phase ratio in the melt. It was suggested that an optimal sinter structure was achieved by mixing a large and dense core ore at about 20 mass% in raw mix. © 2005 ISIJ.