2003 Volume 89 Issue 11 Pages 1099-1106
Using a thermobalance, industrial hematite pellets were reacted with pressurized H2-CH4 mixtures (1-3 atm) at 800-900°C to produce iron carbide in the pellets. H2S having low pressures unable to form FeS was added to the mixtures. First, reduction of iron oxides proceeded and meanwhile carbidization of metallic iron took place. The addition of traces of H2S into gas promoted iron carbides (Fe3C, Orthorhombic) rather than free carbon (soot) or metallic iron as final products with nearly complete carbide conversion. The higher the temperature and the pressurization, the larger the carbidization rates. The tests without H2S gave lower iron carbide contents with much soot or metallic iron. The addition of oxidant CO2or H2O into gas suppressed iron carbides and soot. Initial carbidization rates of a reduced iron pellet coincided with a reaction rate model proposed earlier by Grabke.