Mineralogical features of restored pellets of Northern Mining and Processing Plant (Kryvyi Rih basin)

Abstract

The advantages of reduced iron ore pellets over oxidized ones have been considered. The chemical and physical parameters of the primary material have been given: iron ore (magnetite) concentrate (iron content is 67.30 mass %; particle size distribution is 97.0 % of 0.056 mm fraction), bentonite (montmorilonit content is 70.43 mass %; particle size distribution is 94.5% of 0.056 mm fraction), ground coke. The course of experiments has been described. The zonal structure of the obtained pellets has been characterized: the central zone is composed of hematite with relics of magnetite; intermediate one contains magnetite particles with inclusions of hematite; peripheral zone includes subidiomorphic crystals of magnetite and their dendritic aggregates. The bentonite component in the central and intermediate zones retained a crypto-crystalline structure, in the peripheral one it had been transformed into a crystalline aggregate of garnet and pyroxene. Emphasis is placed on the need to verify the impact of various indicators of temperature, firing time, quantitative ratios of charge components, mineral and chemical composition of the cementing material on mineralogical transformations.