Low Temperature Reduction Mechanism of Carbon-Iron Ore Composite Using Woody Biomass

Utilization of biomass, which is regarded as a carbon neutral fuel, has been discussed to decrease in the carbon dioxide emission from the ironmaking processes. Previous reports insisted the volatile matters in the uncarbonized biomass contributed to the reduction of iron ore at low temperature. However, its mechanism has not been explained by the pyrolysis reaction of biomass components. In this study, the low temperature reduction behavior of the carbon-iron ore composite using uncarbonized biomass was compared with that using its components such as cellulose and lignin. Furthermore, the effect of volatile matters in the biomass on the reduction of iron ores was examined. The composite using uncarbonized biomass was started to be reduced at 400-450 degrees C by CO produced by pyrolysis of cellulose. As the temperature was further increased, iron ore was reduced to metallic iron at approximately 800 degrees C by hydrogen produced by the interaction between cellulose and lignin. The metallic iron may contribute to the gasification of biomass char and fast reduction reaction as the catalyst.