Blast furnace ironmaking system using partially reduced iron ore reduced by an energy source with low carbon content

Abstract

It is possible to improve the productivity and flexibility of the blast furnace operation and also to substitute energy sources in the pig iron production processes by combining the partial reduction process using low carbon content energy sources such as natural gas with the blast furnace process. In this case, the blast furnace process conducts the final reduction and melting of the partially reduced iron ore produced in the partial reduction process. The production rate of the partially reduced iron ore is much higher than that of the fully reduced iron one, because the reduction rate tends to decrease remarkably as the reduction degree rises. As for the technological problems of using the partially reduced ore in the blast furnace process, the deadman temperature might decrease if a large amount of fine iron ore that has been partially reduced is injected. However, if the appropriate amount is used, the reducing agent rate may lower, and productivity can be improved without decreasing the deadman temperature. This method not only reduces energy consumption in the existing blast furnace ironmaking process, but also reduces the energy consumption related to carbon dioxide emission in the total hot metal production processes, including the partial reduction process.