Production of Iron Carbide from Iron Ores in a Fluidized Bed

Abstract

Utilizing an ordinary bubbling fluidized bed, a batch of hematite ores (0.15∼0.21 cm diameter) was reacted at 923∼1 123 K with H₂–CO mixtures to synthesize iron carbide. Sulfur of low pressures unable to form FeS was added to the mixtures. For almost all the conditions, roughly one hour treatment yielded conversion of some types of ores fully to iron carbides as mostly Fe₃C, partly accompanying Fe_xC (x ≈2.5), dependently of the reaction conditions. It was proved that small amounts of gaseous sulfur led to carbides rather than free carbon or metallic iron as final products. The conditions of high temperature and low sulfur pressure provided high quality iron carbides having nearly 0.03 mass% S as low as conventional reduced irons. Their conversion yields seemed to be almost insensitive to the H₂/CO mole ratio and ore type.
From rate analysis for carburization process obtained in a same reactor, it was suggested that this process has several times higher reaction rates than those measured in the conventional Iron Carbide Process gas.