Reduction of Iron Ore by Uncarbonized Biomass in a Rotary Kiln Type Furnace

Utilization of biomass char, which is regarded as a carbon neutral fuel, has been discussed to decrease in the carbon dioxide emission from the ironmaking processes. However, carbonization usually leads to a significant carbon loss. In this study, the direct use of uncarbonized biomass for the reduction of iron ore was attempted. First, reduction behavior of the iron ore-uncarbonized biomass composite was examined to understand the reduction mechanism at elevated temperature. Second, reduction tests using a rotary kiln type furnace were conducted to propose a new reduction process of iron ores. In this process, stainless steel balls are utilized to supply heat and pulverize carbonized biomass and reduced iron ore through collisions with balls. The effect of process parameters on the reduction behavior was examined. Metallic iron formed in the composite of iron ore and uncarbonized biomass by heating over 800°C under inert gas atmosphere. Heating these materials in a rotary kiln type furnace over 950°C also led to metallic iron formation. Increasing in the treatment temperature and time increasd reduction degree. The results showed a possibility that the HSM (heat storage material) balls accelerate the reduction of iron ore, and the carbonization and pulverization of biomass.