鉱石中のマンガンを鋼に直接入れる「直接合金化」の最適条件を体系化～日印連携研究でプロセス設計の指針を提示～

2026-02-09 東北大学

図1. 鋼へのマンガンの添加方法。従来法と比べ新製造法はマンガンを鋼に添加するまでの工程を省略できるが、効率的にマンガンを添加できる条件の探査が不十分であった。

＜関連情報＞

• https://www.tohoku.ac.jp/japanese/2026/02/press20260209-03-Mn.html
• https://www.tohoku.ac.jp/japanese/newimg/pressimg/tohokuuniv-press20260209_03web_Mn.pdf
• https://link.springer.com/article/10.1007/s40831-026-01420-3

中マンガン鋼を生産するための持続可能な直接マンガン合金化法 Sustainable Direct Mn Alloying Practice to Produce Medium Mn Steel

Kakara Sripushpa,Elizaveta Cheremisina,Ryo Inoue,Takayuki Iwama,Shigeru Ueda & Ashok Kamaraj
Journal of Sustainable Metallurgy  Published:23 January 2026
DOI:https://doi.org/10.1007/s40831-026-01420-3

Abstract

Manganese alloying via. direct reduction of MnO in ladle refining slag is a promising alternative to energy and cost intensive conventional ferroalloy production methods. This study explores the aluminothermic reduction of MnO in CaO–SiO₂–Al₂O₃–MgO slag under varying CaO/SiO₂ ratios, Al₂O₃ content, and stoichiometric addition of aluminum for 4 and 8 mass% Mn concentrations in molten iron. The results showed that the slag containing 30 mass% Al₂O₃ suppressed Mn volatilization, whereas Al₂O₃-free slags exhibited a faster MnO reduction but a larger vaporization loss. On the other hand, the slag with CaO/SiO₂ ratio of 2 without second-phase precipitation, facilitating enhanced slag–metal separation and reduced metal droplet suspension, showed significant improvement in Mn recovery of 68%. Furthermore, excessive Al addition leads to higher Mn loss. An empirical equation for Mn loss was developed to correlate Mn loss with factors such as slag basicity, Al₂O₃ content, Mn distribution ratio between slag and metal, and the amount of aluminum added.