2003 Volume 43 Issue 5 Pages 612-619
Simultaneous synthesis of iron carbides (mainly Fe3C) and rutile (TiO2) from natural ilmenite ore (mainly FeTiO3) were examined by thermochemical reactions with H2-CO or H2-CH4 gas mixtures at temperatures of 1 073-1 273 K. The low sulfur pressures incapable of forming FeS was added to these gas mixtures to make stable iron carbides without free carbon. Iron carbide is currently interesting as alternative pure iron sources in steelmaking. The rutile is also available as a feedstock for titanium industry.
First, partial conversion from ilmenite to rutile and metallic iron mostly proceeded and subsequently iron carbidization occurred together with further reduction of rutile. Finally, these processes with both gas mixtures provided iron carbide (Fe3C) and lower titanium oxides such as Magneli phases (TinO2n−1, 4≤n≤9 namely TiO2−x) and/or Ti3O5 rather than rutile.
Reaction time, H2/CH4 ratio, sulfur potential, and temperature dependence of reaction behavior was examined further. The iron carbidization rates were analysed using the first order rate model. Ilmenite samples prepared from reagents showed slightly slower conversion rates to titanium oxides at 1 073 K than the natural ore ones, though both samples showed similar iron carbidization rates.