Solubility of MgO in New Ironmaking Process-typed Slags

Abstract

The solubilities of MgO obtained from the data obtained from equilibrium experiments between liquid CaO-SiO 2 -Al 2 O 3 -Fe t O-MnO slags and liquid silver and solid iron in the temperature range of 1 703 to 1 773 K in a CO/CO 2 gas mixture are analyzed in the current study. The solubilities of MgO decreased with increasing Fe t O content and the slag basicity, (mass% CaO)/(mass% SiO 2 ) in the slag basicity less than 2.0 and they were compared with the change of the MgO solubility with increasing MnO concentration in the slags. The present data were temperature-extrapolated to those at 1 873 K and compared with the previously reported MgO solubilities in steelmaking slags. The application of the optical basicity resulted in correlation of MgO solubility with COREX process-typed slag compositions.

Effect of FeO and Al2O3 on the MgO Solubility in CaO–SiO2–FeO–Al2O3–MgO Slag System at 1823 K

“…According to the detailed description in previously published literature, the optical basicity (Λ) is proportional to the basicity and thus the activity of the free oxygen ions ($a_{{\rm O}^{{\rm 2}- } } $ ). Details regarding the calculation and the coefficients for the slag constituents are provided elsewhere 8, 22. The relationship between optical basicity and MgO solubility in various slag systems 1, 4, 18, 24 and the present work is shown in Figure 2.…”

“…Jung et al6 reported the effect of MnO concentration on MgO solubility and calculated the Mg 2+ capacity of the slag system as suggested by Bergman7 using the MgO activity equilibrated with magnesiowüstite. Furthermore, the Mg 2+ capacity decreased with optical basicity 6, 8, 9…”

“…Recent work done by Brüggman and Pötschke,10 Kwong and Bennett,11 Bennett and Kwong,12 and Kwong et al13 evaluated the MgO solubility in electric arc furnace (EAF) slags at various slag basicities, FeO concentrations, oxygen partial pressures, and temperatures using the FactSage thermochemical software, which seem to qualitatively agree with empirical values published in other works 2, 5, 8…”

“…To extend the refractory life of furnaces, dolomite or MgO are typically added to the slag system to decrease the dissolution rate and the amount of MgO from the refractory and a fundamental understanding of MgO solubility in various slag systems has been the focus of much work 1–18…”

The effect of FetO Content on MgO Solubilities in Lime-based Slags

“…Jung and his coworkers examined the effects of slag composition and temperature on MgO solubilities using the data produced from the research topics about the thermodynamic behaviors of Mn oxide in several metallurgical slag systems. [7][8][9] Recently, the concept of optical basicity has taken significant interest and it has been applied to several metallurgical parameters. And it has been found to be an excellent measure by applying it to capacities of metallurgical data in previous works.…”