Reduction Behavior of Low Grade Iron Ore at Reducing Conditions Simulating Different Zones of Blast Furnace

Abstract

Representative technological samples for Baharia iron ore are collected from El-Gedida iron ore mines at the western desert of Egypt. Baharia iron ore was fired at 1000ºC for 3 hours, then the green and fired samples was isothermally reduced by different ratios of H2/CO/CO2/N2 which closely represent the theoretical reduction conditions in different zones of blast furnace. The influence of reduction conditions on the reduction behaviour and the morphology of the reduced samples were investigated. Reduction behavior is arranged as: (cohesive>thermal reserve>top) zones due to reduction power of different zones which affect the microstructure of reduced samples. As a result of slow reaction at top conditions, reducing gas created tracks within the samples which increase porosity. On the other hand at cohesive conditions, grain growth occurred and small spherical grains of fired samples were semi-melted forming sintered clusters. The comparative reduction behavior for green and fired iron ore was investigated. At cohesive zone, the effect of firing can hardly be distinguished. But at thermal reserve and top zones conditions, the reduction rate of fired samples is greater than that for the green samples and that was confirmed by morphological examination of them.

Keywords

• Reduction
• Baharia iron ore
• Low grade
• Blast furnace