Future Steelmaking Model by Direct Reduction Technologies

Steel production requires iron ore and coal, and accompanies greenhouse gas emissions. The annual production of the world crude steel increased from 0.9 to 1.3 billion tonnes since 2002, and is anticipated to increase due to the continuous economic growth in developing countries especially in Asia. About two thirds of the crude steel is produced by BF-BOF route whose ratio in the total crude steel production has gradually been increasing. The BF-BOF process is an excellent process in terms of productivity and energy efficiency, the process, however requires high grade iron ore and coal, and the large steel production by the BF-BOF route will accelerate the exhaustion of the high grade raw materials. The CO(2) emissions are also anticipated to increase as does the steel production, since approximately 2 tonnes of CO(2) is generated per tonne of steel by the BF-BOF process. On the other hand, world in-use steel stock has been increasing year by year due to the continuous large steel production, and will be recycled as a large amount of scrap to the market in the future. Steelmaking by feeding Iron Nuggets to EAF together with the scrap can significantly decrease the CO(2) emissions while satisfying the steel quality by diluting the impurities containing in the scrap, as well as conserving the natural resources of high grade iron ore and coal. Steel production by using the direct reduction processes together with the scrap is a suitable and reasonable solution for a sustainable iron and steel making.