Abstract: Reformed coke oven gas (COG), a high quality raw material in steelmaking, can be used to produce direct reduced iron (DRI). In this work, the influences of H2/CO ratio and temperature on the reduction rate and carbon deposition behavior during the reduction process of iron ore are investigated by thermo- gravimetric analysis. The experimental results show that the reduction capacity of H2 is higher than that of CO. The reduction rate increases with the increase of H2 concentration in the mixture gases. When H2/CO ratio is higher than 8/2, the influence of H2 concentration in the mixture gases on the reduction rate decreases. Carbon deposition is observed in the later stage of the COrich gases reduction process. The carbon deposition rate decreases with the increase of H2 concentration in the mixture gases. Carbon deposition occurs preferentially at low temperature. When the temperature is above 850 C, carbon deposition is suppressed.

Key words: carbon deposition, direct reduction, hydrogen-rich gas, iron ore pellet