Ironmaking process using ammonium salt as an auxiliary material: reaction behavior of oxides present in iron ore with NH₄Cl

The iron and steel industry has faced increasing pressure to achieve carbon neutrality, resulting in intensive research on hydrogen-based ironmaking and large-scale electric arc furnace processes. However, significant cost increases are unavoidable and critical challenges, including the reduction of limestone consumption, effective utilization of low-grade iron ores, limited applications of steelmaking slag, and the recovery of strategic elements such as Mn and P, must be overcome even if these technologies are realized. In this study, a novel ironmaking concept, referred to as ammonium salt ironmaking, which uses NH4Cl as an auxiliary material, is proposed and fundamentally investigated. The reaction behaviors of the major oxide components in the iron ores with NH4Cl were experimentally examined, focusing on the separation of Fe, Mn, and P. The results showed that Fe was selectively volatilized as Fe2Cl6 at relatively low temperatures, Mn was converted into water-soluble chlorides, and P was predominantly distributed in the solid residue. Experiments using actual iron ore samples revealed separation behaviors consistent with those observed in reagent systems, confirming the selective distributions of Fe, Mn, and P. Thus, the proposed process enables limestone-free ironmaking without generating conventional steelmaking slag. Moreover, it offers the potential for high-purity Fe production while recovering Mn and P, providing a promising alternative pathway for sustainable iron and steel production.