Recrystallization of Fe2O3 During the Induration of Iron Ore Oxidation Pellets
Magnetite and hematite concentrates are the two main raw materials for oxidized pellet production. Magnetite concentrates have more predominance due to the heat release by oxidation during roasting and may reduce energy consumption (Jiang et al., 2008; Li et al., 2009). However, with the continuous consumption of iron resources driven by the rapid development of iron and steel industry, magnetite resources are becoming scarce and so the development of pellet production is restricted to some extent. Thus, it is imperative to make better use of hematite resources to meet the raw material supply for pellet production (Xu, 2001).
Fundamental investigations of differences in bonding mechanisms in iron ore sinter formed from magnetite concentrates and hematite ores
Abstract Whilst increasing amounts of imported hematite ores are being added with the magnetite concentrates that dominate sinter blends in the People's Republic of China, little is known about the fundamental behaviour of magnetite concentrates during sintering compared to hematite ores. Compacted tablets of fluxed magnetite, magnetite–hematite and hematite concentrates and ores were fired under simulated sintering conditions in the laboratory to establish the fundamental differences in sintering behaviour, mineralogy and bonding mechanisms between magnetite concentrates and hematite ores. Sinter made from magnetite concentrates ( In contrast, hematite ores with high (>2.0) effective basicity are able to form a high tumble strength sinter matrix composed of a network of abundant calcium ferrites (e.g. SFCA, SFCA I) below 1300 °C.
Influence of MgO addition on mineralogy of iron ore sinter
The influence of MgO addition on sinter mineralogy was studied on sinters produced in a laboratory installation, with a wide range of MgO/CaO ratios at several basicity indices [B = (CaO + MgO)/ (SiO2 + A12O3)] between 0.7 to 1.9. The most striking influence of MgO is the suppression of hematite and Ca-ferrite phases and the increase in magnetite phase. In general, MgO favors the formation of glass and suppresses the precipitation of dicalcium silicates in favor of Ca-Fe-Mg olivines and pyroxenes. Microprobe studies revealed that most of the Mg was picked up by the magnetite phase to form mixed spinels of type (Fe, Mg)O · Fe2O3. At a constant basicity index, increased replacement of CaO by MgO also led to increased participation of FeO in the slag formation process, thus increasing the overall FeO content of sinter. A mechanism for the formation of mixed spinels has been proposed. The effect on various sinter properties resulting due to change in sinter mineralogy has been outlined.