Ironmaking by direct reduction of iron ore-biomass composite pellets using biomass syngas

In order to ease the shortage of fossil energy and to come up to the stricter effluent standard, this article introduces an innovative green ironmaking technology integrated of the direct reduction process and the development and utilization of biomass energy. Biomass was mixed together with iron ore powder and additives for producing green pellets. Hydrogen-rich syngas produced by biomass catalytic gasification was used as a reducing agent, and the heat produced by biomass combustion was used as the heat source of pellet preheating and reduction. Investigations on the effects of preheating, reduction temperature and green pellet size on the quality of direct reduction iron (DRI) show that increasing the preheating and reduction temperature and decreasing the pellet size can improve the quality of DRI. When iron concentrate with the iron grade of 65.21% was taken as raw materials, high-quality DRI with the total iron TFe of 86.1% and the metallization rate of 94.9% can be obtained at optimum operation conditions (pellet size of 8 to 10 mm, preheating at 900℃for 30 min and reduction at 1000℃ for 30 min).