In the recent years, iron carbide is considered as a new material with high carbon content for steelmaking process. This is due to special features of cementite such as being non-flammable, easy traortation and storage and high carbon content, which is useful as a source of energy. As thermodynamic view, iron carbide is a metastable phase, which can decompose to metallic iron and graphite. Hence, the effective parameters on the stability of cementite were studied in the recent decades. The results showed that temperature, atmosphere, kind of the iron ore and additives are the most important parameters in the stability. Among the additives, Mn and MnO 2 have received less attention. Therefore, the effect of Mn and MnO 2 on the formation and stability of cementite during reduction and carburizing process of iron ore was surveyed in this study. First, hematite powder with 5 and 10%wt Mn and MnO 2 was mixed, where 10% naphtha was added as a cold binder. Raw samples with 9 and 5mm diameter and height respectively, were compressed under 500N force and sintered for 4 hours at 900°C. Reduction and carburizing processes were performed in a packed bed reactor at 750°C for different times of reaction, where atmosphere contained 10% Ar, 30%CH4 and 60% H 2 . The weight analysis results showed that hematite was reduced to iron and then carburized. Based on these results, after 5min reduction process of hematite more than 95%wt iron was produced. The formed iron, as a catalyst for dissociation of methane to form activated atomic carbon, was the main reason of carburizing with a acceptable rate of reaction. Increasing time of process increased the formed cementite in the samples, where the maximum amount of cementite was formed at 15 min. The studies showed that Mn increased the rate of reduction, while MnO 2 has a opposite effect. Increasing the amount of Mn from 5%wt to 10%wt has not a significant effect on reduction rate, but the MnO 2 has a significant effect on this process. Mn increased the stability and the rate of cementite formation and MnO 2 just stabilized the carbide. Also, microstructure studies showed that the formed carbide in pure samples with no additives has a Layer and massive morphology, while Mn and MnO 2 change this morphology to the spherical form. Keywords: Iron, Iron carbide, Reduction, Carburization, Hematite, Manganese, manganese Oxide
