technology

Steelmaking in an electric furnace, which uses reduced scraps, can reduce CO₂ emissions, and is said to have the potential to achieve carbon-neutral steelmaking if green electricity can be used for heating. However, that cannot be realized unless a necessary and sufficient amount of scraps can be procured. In addition, scraps are known to contain impurities such as metal elements other than iron which would degrade the characteristics of steel materials.
In this project, we will work to develop a technology for manufacturing high-grade steel by melting reduced iron manufactured by a direct reduction process. An electric furnace is less productive than a blast furnace, and in particular, it is said that it takes time to melt reduced iron manufactured by a direct reduction process. In this project, we will study measures to remove impurities (such as phosphorus and nitrogen) and efficient methods for melting reduced iron.

2 Development of Direct Hydrogen Reduction Technology to Reduce Low-grade Iron Ore Using Only Hydrogen[2] Development of Technology to Remove Impurities in Electric Arc Furnaces Using Directly Reduced Iron

• Develop the technology to produce high-grade steels that can be used for automotive outer panels, etc., in the electric arc furnace process utilizing hydrogen direct reduced iron from low-grade iron ore. Demonstrate the technology to control the concentration of impurities (components affecting the product) to the same level as the blast furnace process (150 ppm or less of phosphorus and 40 ppm or less of nitrogen) in the large-scale integrated electric arc furnace process (with a processing capacity of approx. 300 tons) by 2030.

• Development of element technology and verification in a small-scale test electric arc furnace and secondary refining (with a processing capacity of 3–10 tons)
• Demonstration test in a large-scale test electric arc furnace and secondary refining (with a processing capacity of approx. 300 tons)

※図を拡大して見ることができます。

Development of a direct hydrogen reduction technology for reducing low-grade iron ore with hydrogen alone[3] Development of technologies such as high-efficiency melting by an electric smelting furnace (ESF) using directly reduced iron

• Demonstrate a technology to realize the production efficiency (pig iron production rate of 100 tons/hr or more) which can achieve replacement of the blast furnace method and to control concentration of impurities in the produced iron on a par with the blast furnace method (e.g., phosphorus 0.015% or less) by an integrated process of hydrogen direct reduction – electric smelting furnace (ESF) – converter using low-grade iron ore. Also demonstrate a technology for controlling slag produced as a by-product in electric smelting furnaces (ESF) to a quality level suitable for domestic cement applications (equivalent with blast furnace cement, e.g. iron oxide 3% or less)

• Development of element technology and preliminary verification by numerical simulation
• Demonstration test in a test electric smelting furnace (ESF) (approx. 10m in diameter)

※図を拡大して見ることができます。