Steelmaking technology for a sustainable society

Abstract

For the reduction of CO2 emission, two major developments are being conducted in COURSE50 (“ CO2 Ultimate Reduction in the Steelmaking Process by Innovative Technologies for Cool Earth 50”). The one is separation of CO2 gas from BFG (Blast Furnace Gas) and recharge of the rest of BFG including H2 and CO into blast furnace. Hydrogen iron ore reduction technology is also going to be developed. The other one is amplification of H2 gas from CH4, for example, in COG (Coke Oven Gas). The produced hydrogen gas will be supplied to the society or the reformed COG will be charged to blast furnace. In addition to these drastic challenging technology developments, a variety of measures for CO2 reduction is under taken. In the frame of Asia–Pacific Partnership on Clean Development and Climate, the best available technology for energy savings are discussed to be transferred within seven member nations, which has the effect of 1.27 million ton reduction of CO2 emission a year. By supplying energy saving steel products to society such as high strength steels for automobiles and ships, which realizes the fuel consumption reduction, high performance electrical steels for motors and transformers, which realize electricity loss reduction, and by recycling waste city plastics and tires in steel processes for hydrogen gas generation, chemical raw material conversion and iron ore reduction, etc., it is expected that equivalent 10% reduction of CO2 gas emission in steel production is counted. In steelmaking process the reduction of refining slags contributes materials use efficiency and less emission of unuseful byproducts. The control and utilization of nonmetallic inclusions, such as deoxidation products, are one of the key technology for obtaining product performance, which is required in the above-mentioned steel products. In order to optimize steelmaking process for these purposes, computational thermodynamics is applied. Optimization of demanganization, and control of chemical composition of nonmetallic inclusions by the use of computational thermodynamics are mentioned.