Low Temperature Gaseous Reduction of Iron Ore in the Presence of Alkali

Influence of SiO₂ and/or MnO₂ on the Reduction Behaviour and Structure Changes of Fe₂O₃ Compacts with CO Gas

“…(4) The presence of silica had a negative effect on the size and number of metallic iron plates and whiskers result in small increase in the volume of compacts (DVϭ58 %) compared to 255 % in pure Fe 2 …”

“…They found that the formation of fayalite (2FeO · SiO 2 ) at later stages in presence of noncrystalline silica results in a deceleration in the reduction rate compared with crystalline form of silica. Mc-Geoge et al 2) found that the presence of silica increases the reducibility of ferric oxide. Baldwin 3) found that the formation of fayalite can occur during the reduction of iron ores if the reduction temperature is higher than 1 073 K or during sintering when ferrous oxide and silica are present in absence of lime (CaO).…”

“…El-Geassy 5) studied the influence of SiO 2 on the gaseous reduction of wüstite micropellets with H 2 , CO and H 2 -CO mixtures at 1 173-1 373 K, he observed that the highest rate at the initial stages was obtained in H 2 and the slowest was in CO, while with mixtures of gases the rate did not vary with the gas composition and the presence of SiO 2 enhanced the reduction in CO and retarded the reduction in H 2 . Atui et al 6) studied joint reduction of the oxides Fe 2 O 3 , MnO 2 , and NiO with carbon in an inert atmosphere. They found that the freshly reduced metallic phases accelerate oxide reduction while the solid-phase oxide interaction can retard oxide mixtures metallization.…”

“…It was found that impurities and associated gangue minerals play an important role on the reduction of iron oxides by its affect the swelling of pellets. [8][9][10] 2 ) compacts annealed at 1 473 K for 6 h were prepared. The different phases were identified by Xray diffraction (XRD) and their structures were examined by optical and scanning electron microscopes.…”

“…In MnO 2 -containing samples, the reduction rate was retarded at initial stages due to the presence of manganese ferrite. At later stages, the formation of fayalite-manganoan [(Fe, Mn) 2 SiO 4 ] greatly hindered the reduction process. A catastrophic swelling (DVϭ 405 %) was recorded in 6%MnO 2 -Fe 2 O 3 compacts and was greatly diminished to 55.95 % in presence of 7.5 % SiO 2 due to the decrease in size and number of metallic iron whiskers and plates.…”