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Desulfurization of molten iron by molten slag is an electrochemical reaction. Previous investigations confirmed that applying electricity could enhance the desulfurization of molten iron, but a quantitative relation between the electricity and the desulfurization was not fully elucidated. The present study attempted to correlate the extent of the electrochemical desulfurization with the applied electricity via a series of high-temperature desulfurization experiments and thermodynamic analyses. A molten iron containing C and S was allowed to react with CaO– $$\hbox {Al}_{{2}}\hbox {O}_{{3}}$$ – $$\hbox {MgO}_{\text {sat.}}$$ slag at 1673 K (1400 $$^\circ $$ C), with and without the electricity of constant current. S distribution coefficients ( $$L_{\text {S}}$$ = (pct S)/[pct S]) were obtained after the normal and the electrochemical equilibria, respectively. The obtained results were interpreted by employing the Nernst equation in order to extract the potential difference ( $$\varDelta \phi _{\text {S}}$$ ) for the electrochemical desulfurization. It was found that applying electric current (I) increased the $$L_{\text {S}}$$ after the electrochemical desulfurization, which resulted in the increase of $$\varDelta \phi _{\text {S}}$$ . A resistance, $$R_{\text {DeS}} = \varDelta \phi _{\text {S}}$$ /I, or a specific resistivity, $$\rho _{\text {DeS}} = \varDelta \phi _{\text {S}}$$ /(I/A), where A is the cathodic area, for the electrochemical desulfurization was defined, which can be used to characterize the susceptibility to the electrochemical desulfurization. It was found that $$R_{\text {DeS}}$$ was independent of the I within the range of this investigation, decreased as (pct CaO)/(pct $$\hbox {Al}_{{2}}\hbox {O}_{{3}}$$ ) increased and was proportional to the resistance of the slag ( $$R_{\text {slag}}$$ ). A favorable condition for the electrochemical desulfurization is not the same as that for the normal desulfurization condition. The $$\varDelta \phi _{\text {S}}$$ , which is an indicator of the extent of electrochemical desulfurization, was independently predicted by employing a thermodynamic model for the oxysulfide slag. The model prediction was in a good agreement with the experimental data. The model was used to predict necessary current level for a desired electrochemical desulfurization.

Professor Fruehan has been a pioneer in the fundamental understanding of slag foaming in ironmaking and steelmaking processes. Although considerable progress has been made in our understanding of the phenomena, there are still unanswered questions regarding the mechanisms in industrial processes and how to control them. At McMaster University, we have been working on conditions that are relevant to foaming in electric arc furnaces (EAFs) where these phenomena are central to modern EAF practices. This work will be reviewed and put in the context of what is known from a fundamental standpoint.

With a goal to estimate the sulfide capacities of slags used in the pretreatment of hot metal, the sulfide capacities of CaO-Al2O3-SiO2 slags were measured at 1673 K to 1773 K (1400 °C to 1500 °C). The gas–slag equilibrium technique has been used for this measurement. From the results obtained, it was found that the temperature dependence of the sulfide capacity of this slag is independent of the slag compositions. Therefore, a new empirical model based on optical basicity for sulfide capacity estimation of this slag was developed using the measured values of the current work and literature. With the use of the new model, the isosulfide capacity curves at 1673 K (1400 °C) were mapped.

In this article, a novel thermodynamic model—the molecular interaction volume model (MIVM)—was employed to predict the activities of three components in the ternary molten slag CaO-FeO-SiO2 at different temperatures. The results show that the predicted values of activity of CaO and SiO2 are in reasonable agreement with the experimental data in a range of lower concentrations, which are about xCaO

In the present work, a solid solution of 3CaO · V2O5 and 3CaO·P2O5 was found below 1573 K. The solution could be described as 3CaO+xV2O5+(1−x) P2O5. The solid solutions at three compositions, namely, X=1/3, X=1/2, and X=2/3, were synthesized. X-ray diffraction (XRD) patterns revealed that the crystals exhibited a rhombohedra structure. X-ray indexes at these compositions were reported.