Influence of iron ore concentrate quality on metallurgical properties of pellet

Abstract

One of the important factors for improving the technical and economic performance of blast furnaces is the iron content in the iron ore part of the charge. At the same time, there is evidence that when using iron ore concentrate with an iron content of more than 66‒67% for the production of pellets, their strength decreases, and adjustments to the heating modes are required. In recent years, Russian mining enterprises have been implementing technological measures to increase the mass fraction of iron in the concentrate to 68‒70%. The results of a study of the influence of concentrate quality indicators (mass fraction of iron, specific surface value) on the pelletizing technology and metallur-gical properties of pellets are presented. Concentrates with a mass fraction of iron of 66.6, 68.0, 69.2% and a specific surface of 1576, 1999, 2015 cm2/g, respectively, were used as an object of study. It was found that increasing the iron content and specific surface area in the concentrate leads to an improvement in the raw pelletizing technology ‒ plasticity and the proportion of pellets with a size of 5‒16 mm increase. Roasting of laboratory pellets in baskets on a roasting machine showed a multidirectional change in the metallurgical properties of the pellets. The compressive strength index decreased, the hot strength changed little, the softening-melting temperature range (SMTR) decreased from 308 to 200‒290 °C. Mineralogical studies have established that the decrease in these indicators (strength and SMTR) was influenced by a decrease in the amount of silicate binder and the uneven distribution.