Work

Potential-dependent removal of Cu, Sn, Ni, and Cr from molten Fe in contact with FeS-containing slag

Year: 2026

Type: article

Abstract: The accumulation of tramp elements in scrap-derived steel is a major obstacle to high-grade steel recycling. In this study, the effects of polarization on the migration of Cu, Sn, Ni, and Cr from molten iron to an FeS-containing oxysulfide slag were investigated using first-principles molecular dynamics calculations and constant-potential electrolysis. The calculations showed that sulfur is preferentially stabilized near the molten metal–slag interface, and that its valence state is strongly influenced by local Fe coordination, suggesting that sulfur-bearing species can actively participate in interfacial electrochemical reactions. Electrolysis experiments revealed strong element-dependent removal behavior. Sn was preferentially removed under a wide range of conditions with an apparent removal ratio of 95.0%, whereas Ni removal was negligible. Although Cr was also removed, its migration was affected by Sn coexistence and the applied potential. Cu exhibited limited depletion under the present multicomponent conditions. These results suggest that Sn removal is promoted by the interfacial enrichment associated with its low surface tension, followed by a reaction with FeS-derived sulfur species. The findings provide insights into the selective electrochemical refinement of tramp elements from molten iron.

Source: Scientific Reports

DOI: 10.1038/s41598-026-73440-8

Authors: Masahiro Ambiru, Shungo Natsui, Akihisa Ito, Miho Hayasaka, Hiroshi Nogami

Institution: Tohoku University

Language: English

Topic: Metallurgical Processes and Thermodynamics

Subfield: Mechanical Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,690

Funders: Steel Foundation for Environmental Protection Technology, Japan Society for the Promotion of Science