Toward Modeling of Electrochemical Reactions during Electroslag Remelting (ESR) Process. Issue 5 (17th March 2017)

• Record Type: Journal Article
• Authors: Karimi‐Sibaki, Ebrahim; Kharicha, Abdellah; Wu, Menghuai; Ludwig, Andreas; Bohacek, Jan
• Is Part Of: Steel research international. Volume 88:Issue 5(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-03-17
• Subjects: activation overpotential -- concentration overpotential -- electric potential -- electroslag remelting (ESR) -- faradaic reaction -- ferrous ion -- numerical modeling; Steel -- Periodicals; Steel -- Metallurgy -- Periodicals; 669.142
• DOI: 10.1002/srin.201700011
• Languages: English
• ISSNs: 1611-3683

Abstract

Abstract : Electrochemical reactions always occur at the electrode–slag and slag–metal melt interfaces during the electroslag remelting (ESR) process. However, those reactions together with the ion transport phenomenon in the molten slag region are still poorly understood. A numerical model considering both the ion transport and the electrochemical reactions is demanding. For this purpose, a numerical model is proposed. The ion transport is modeled by solving the Poisson–Nernst–Planck (PNP) equations, while the kinetics of the reaction at the slag–metal interface is modeled with the well‐known "Butler–Volmer" formula. Demonstratively, a one‐ dimensional case is calculated: a DC electric current is applied to a molten multi‐ion slag (CaF2 –FeO) between the anode and the cathode. The modeling results show that the redox reaction occurs only for the ferrous ion (Fe 2+ ), not for other ions at low current density (<2 kA m −2 ), which was verified experimentally. We also find that formation of ferric iron (Fe 3+ ) or discharge of calcium at large current density (>5 kA m −2 ) may not take place, although some researchers have proposed such a hypothesis. Therefore, further research steps are suggested to verify this point so that the model is fully applicable for the industrial ESR process. Abstract : Electrochemical reactions always occur at the slag–metal melt interface during electroslag remelting (ESR). A novel model considering both the ion transport and the electrochemical reactions is proposed. The model enables us to calculate vital parameters such as activation and concentration overpotentials for complex slags involving multiple ions.