Makoto EGASHIRA, Takayuki MAEDA, Kouki NISHIOKA and Hiroshi NAKAGAWA Synopsis : The purpose of this investigation is to examine the effect of properties (porosity, specific surface area, particle size distribution and impurities) of hematite pellets on the synthesis of Fe3C pellets. The experiments were carried out by using six kinds of reagent hematite pellets with H2-CH4 (70 : 30) gas mixture at 750•Ž. The synthesis of Fe3C pellets were confirmed all kinds of hematite pellets except two kinds

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... of ones One of the most suitable pellets for the synthesis of Fe3C was converted to high purity Fe3C (on XRD level) within about 110 min and the phase was stable at least for 3 h, even though excessive carbon deposited at the surface of pellets. Excessive carbon deposition could be stopped with lowering CH4 concentration to an equilibrium gas composition for Fe3C generation reaction. Two kinds of pellets contained relatively low impurities did not form Fe3C. Such high purity pellets tended to shrink due to sintering during reduction stage, and the structure of reduced iron had much less micro pores. This phenomenon might cause decrease of adsorption sites for CH, molecule and therefore the enough carbon deposition necessary for Fe3C formation hardly could occur. The correlation between other properties (porosity, particle size distribution) and Fe3C formation was not confirmed in detail.