Interfacial tension between molten iron and CaO-SiO2 based fluxes

Flux-metal interfacial tension has been examined by X-ray photography of a metal drop melted in a molten flux. The experiments were carried out at 1 580 degrees C using a zirconia crucible with low solubility in the fluxes. The systems used in the investigation were as follows: Metal phase: Fe-O alloy, oxygen content in the alloys varied from 0.002 to 0.070 mass%. Flux phase: Ternary system: CaO-SiO2-M-x(F,O)(y), where M-x(F,O)(y) represents NaF, CaF2, Al2O3, Na2O, MgO, Li2O or ZrO2 and concentrations varied from 2 to 40 mass%. Multicomponent system: CaO-SiO2-Al2O3-Fe2O3-Na2O-NaF-CaF2-MgO-Li2O-ZrO2. The interfacial tension was observed to increase with increasing NaF, CaF2, Na2O, MgO or Li2O contents, while only minor changes in the values were observed with varying Al2O3 or ZrO2 contents in CaO-SiO2 or CaO-SiO2-Al2O3 systems. The interfacial tensions between flux and molten iron decreased with increasing oxygen activity in iron, gamma = gamma(0)-0.324In(1+116a(0)).