Interfacial tension between molten iron and CaO–SiO₂–MgO–Al₂O₃–FeO slag system

Abstract

The interfacial tension of the CaO-Al 2 O 3 -SiO 2 -MgO-FeO slags with liquid iron at 1550uC was investigated using a synchrotron X-ray beam source. The interfacial tensions of molten slag with liquid iron increased continuously with increasing CaO/SiO 2 ratio for both CaO-SiO 2 -MgO and CaO-SiO 2 -Al 2 O 3 -MgO slag systems. However, the contents of MgO and Al 2 O 3 exceeded the saturation limit and the apparent interfacial tension decreased markedly. This decrease was attributed to formation of a solid phase at or near the interface: MgO particles for MgO saturation and MgAl 2 O 4 particles for Al 2 O 3 saturation. It was found to be oxygen in iron that exerts a dominating influence on the interfacial tension. Its influence was so dominant that all other compositional effects were insignificant. The effect of oxygen was quantitatively determined by employing the Gibbs adsorption and Langmuir isotherms.

Interaction Steel/Slag/Submerged Entry Nozzle and its Impact on Refractory Wear – Thermochemical Process Simulation

“…It is clear that the formula of Borgmann 14) overestimates σ for low oxygen content, as it contains the logarithm of the oxygen content as a subtrahend. In contrast, the equation provided by Park et al 16) is based on the Gibbs isotherm for adsorption and relates the interface tension to the oxygen activity. Therefore, the latter work 16) is used here to calculate Δσ from the simulation results.…”

“…In contrast, the equation provided by Park et al 16) is based on the Gibbs isotherm for adsorption and relates the interface tension to the oxygen activity. Therefore, the latter work 16) is used here to calculate Δσ from the simulation results. For the case of LC steel, it yields Δσ=150 mN/m 20 minutes after the start of casting, and it depends only slightly on time.…”

“…14) From a more recent work of Park et al 16) a value of 94 mN/m would follow for the same example. It is clear that the formula of Borgmann 14) overestimates σ for low oxygen content, as it contains the logarithm of the oxygen content as a subtrahend.…”

“…Numerous investigations deal with the dependence of surface and interface tension on the oxygen content; some of these results are provided here. 9,[14][15][16] It was observed that, for a given oxygen content, different mold slag compositions have only a minor effect on the interface tension. 9,16) The aluminum content is of interest in the case of the TRIP steel investigated here.…”

“…9,[14][15][16] It was observed that, for a given oxygen content, different mold slag compositions have only a minor effect on the interface tension. 9,16) The aluminum content is of interest in the case of the TRIP steel investigated here. Sun 15) observed only a slight increase in interface tension, which appears to not be relevant for the contents considered here.…”