Professor Yagi is a well-known figure for his deeply impact in metallurgical processes including raw materials processing, conventional and developing ironmaking processes, energy evaluation, CO2 emission reduction and relating materials synthesis, especially in their application for developing sustainable technologies. He has dedicated himself to research and education mainly in Tohoku University, Japan and, as a visiting professor, in some universities outside Japan. Thus, over 200 original papers have been published on his research results and many excellent researchers and engineers who studied in his laboratory are now working in many countries. Throughout his career, his activity has impacted various fields, such as:
Blast Furnace Modeling
A mathematical model of the blast furnace was developed. The model can evaluate production rate and energy efficiency together with estimation of in-process phenomena like fluid flow, heat transfer and chemical reactions in three dimensions, thus very useful for the production control and also improvement of practical operations. The model is therefore being used worldwide in academic researches and industrial technology developments.
The energy evaluation technique applying exergy analysis was proposed and hence replacing conventional enthalpy balance with the exergy balance which is more accurate. The proposed method has already used widely in Japanese ironmaking industry to realize reduction of energy consumption in industrial processes.
Recovery and Utilization of Waste Thermal Energy
For the recovery of waste thermal energy at high temperature, a method to use high temperature phase change materials was proposed for increasing recovery efficiency. A rotary cup process to produce granular slag with recovery of high temperature thermal energy from molten blast furnace slag was developed.
Reduction of CO2 Emission and Methanol Synthesis
Reduction of CO2 emission which is strongly requested to ironmaking industry was studied for improving operations of conventional ironmaking processes by advancement of reaction kinetics on combustion of coke and reduction of iron ores for realizing low temperature operation of the blast furnace. Reforming of wasted CO2 was studied to be changed to synthesize methanol.
The scrap melting shaft furnace proposed is a superior process to decrease CO2 emission. Kinetic study on carbon absorption of scrap, which is important to decrease iron melting temperature, was fundamentally studied and successfully applied to the evaluation of the shaft furnace process.
Processing of low quality ore, laterite which contains low-Ni, high-Fe was studied fundamentally and an effective process through preheating, selective reduction and leaching of Ni, Co, magnetic separation of magnetite from the other oxides, and oxidation/reduction of magnetite to Fe was proposed to enable the effective use of untapped laterite resource.
Self-Propagating High Temperature Synthesis (Combustion Synthesis)
Combustion synthesis was applied to develop a low energy consumption process for synthesizing hydrogen storage compounds to recover waste thermal energy.
He also devoted to the education for the worldwide spread of sophisticated metallurgical process engineering, as a result students/researchers studied in his laboratory are now contributing to academic and industrial research in and around ironmaking field in many countries. In addition, he actively worked as a leader of some research projects on the ironmaking blast furnace in the iron and steel institute of Japan and others, and also as chairman of 54th committee (ironmaking) in Japan society for promotion of science. Through these social activities, he has contributed significantly to the advancement of metallurgical process engineering as well as technology improvement in the ironmaking field.
FLOGEN STARS OUTREACH is a not-for-profit, non-political and all-inclusive science organization that takes no sides in political, scientific or technological debates. We equally welcome, without reservations, all spectrum of ideas, theories, technologies and related debates. Statements and opinions expressed are those of individuals and/or groups only and do not necessary reflect the opinions of FLOGEN, its sponsors or supporters.