Elucidation of Nitrogen Absorption in Molten Metals in Electric Furnaces

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K20479
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0401:Materials engineering, chemical engineering, and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Muneoka Hitoshi 東京大学, 大学院新領域創成科学研究科, 助教 (50908803)
• Project Period (FY): 2021-08-30 – 2023-03-31
• Keywords: 鉄鋼精錬 / 電気炉製鋼 / アークプラズマ / 窒素吸収 / 発光分光測定

Outline of Final Research Achievements

We have conducted basic measurements of nitrogen absorption phenomena at the arc/molten iron interface, which is important for a drastic change in the ironmaking process (from the blast furnace to the electric arc furnace) toward carbon neutrality. An original experimental system was constructed in a high-temperature furnace with an arc control system, optical measurement system, and sampling mechanism. As a result, it was found that nitrogen-based active species spread outside the emission region of the arc. It was also found that the emitting species and arc temperature distribution varied depending on the ambient temperature, and it was shown that arc strain on the anode (molten iron) side may be stronger when the ambient temperature is higher. Thus, we demonstrated the usefulness of the high-temperature experiments and obtained basic knowledge of arcs on molten iron, which is necessary for clarifying nitrogen absorption phenomena in the future.

Free Research Field

プラズマ材料科学

Academic Significance and Societal Importance of the Research Achievements

日本で最大のCO2排出源となっている鉄鋼業のカーボンニュートラル達成に向けて、製鉄プロセスの抜本的転換（高炉法→電炉法）が重要であり、その実現のために、本研究で対象としたアーク/溶鉄界面の窒素吸収現象の解明が求められている。本研究は本現象の基礎的知見を明らかにしたものであり、特に炉内の温度をアークとは独立して制御することで周囲温度がアークの広がりに与える影響を測定できた。これは、アーク溶接等の他分野における室温環境での研究と、本研究で主眼とする電炉内の高温環境におけるアーク研究を橋渡しするものである。