Formation Behavior of Iron Carbide in a Pellet with H2-CH4 Gas Mixtures Containing Traces of H2S
Shoji HAYASHI, Yoshiaki IGUCHI
Using a thermobalance, industrial hematite pellets were reacted with H2-CH4 mixtures at 800950°C to produce iron carbide in the pellets. H2S of 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 or metallic iron as final products with nearly complete carbide conversion. The higher the temperature, the larger the carbidization rates. The sulfur index in gas around is=0.05 provided high yields of iron carbides with low sulfur content of less than 0.05 mass% S. The tests without H2S gave lower iron carbide contents with much free carbon (soot) or metallic iron. Initial carbidization rates of a reduced iron pellet coincided with a reaction rate model proposed earlier by Grabke.
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