Formation behavior of iron carbide pellet with H-2-CO gas mixture including small amounts of H2S gas

Using a thermobalance, a hematite pellet was reacted with H-2-CO mixtures a t 973 similar to 1073K to produce an iron carbide pellet. H2S of low pressu res unable to form FeS was added to the mixtures. First, reduction of iron oxides proceeded and then carbidization of metallic iron occurred. Small am ounts of H2S in gas led to iron carbides (Fe3C, Orthorhomhic) with complex conversion rather than free carbon or metallic iron as final products. In l ater stage of carbidization, higher iron carbide (Fe2.5C Monoclinic) appear ed partially in lower temperatures, The conditions of higher temperature an d low sulfur pressure provided high quality iron carbides having nearly les s than 0.03 mass% S, The tests without H2S provided loner iron carbide cont ents with much free carbon or metallic iron. Carbidization rates of a reduc ed iron pellet were analysed by an unreacted core model to investigate this process, The carbidization proceeded more rapidly in lower temperatures.