Wetting of Solid Al2O3 with Molten CaO-Al2O3-SiO2

Abstract

The wetting behavior of solid Al 2 O 3 with molten CaO-Al 2 O 3 -SiO 2 was investigated at 1 873 K using the sessile drop method. A new model was developed to represent the time dependence of the contact angle, i.e., the spreading behavior of a liquid drop on a solid substrate. The model takes into consideration chemical interactions which continually take place at the interface between the solid Al 2 O 3 and molten CaOAl 2 O 3 -SiO 2 . By applying the model to the experimental results of the present study the equilibrium contact angle between the liquid slag and solid alumina was determined for a number of different slag compositions, and an iso-contact angle diagram was constructed. The equilibrium contact angle was greatly affected by the slag composition, and it was found that the interfacial tension was the major factor governing the equilibrium contact angle. In the region of low SiO 2 content, the slag with higher CaO content exhibits a smaller contact angle, i.e., better wettability with alumina. For slag with a given CaO/SiO 2 ratio, an increase in Al 2 O 3 results in a corresponding increase in the contact angle, i.e., decrease in wettability. For a given CaO/Al 2 O 3 ratio, the variation of the contact angle with SiO 2 content shows a minimum. The contact angle decreases by increasing the surface roughness of the alumina substrate.

Dissolution Kinetics of Alumina into Mold Fluxes for Continuous Steel Casting

“…In this regard, a high wettability of molten flux with inclusions and a high inclusions dissolution rate is highly preferable in the practical process. 1,2) Dissolution of oxides including alumina in molten slag/flux has been studied by several researchers. [3][4][5][6][7][8][9][10][11] It was reported that the dissolution rate of alumina is influenced by many factors, e.g.…”

Effect of Slag Composition on Wettability of Oxide Inclusions

“…at extended times θ tended to the same value for the slags tested. Further, it was also found that the Choi and Lee spreading model 5) appeared to represent the data well and showed promise as a tool for understanding the effects of slag theremo-physcial properties on wetting. It was not possible to be more definitive with respect to the model as only a limited number of slags on one substrate (spinel) was assessed.…”

“…5) This change is likely to be principally due to the reaction of the slag with the substrate but may also contain a momentum component due to the slag addition technique.…”

“…This longer time is likely due to a combination of both the drive to equilibrium (thermodynamic factor) and resistive forces associated with the viscosity of the slag. The effect of slag viscosity is further discussed when applying the Choi and Lee 5) dynamic wetting model. The wettability of each specific slag on different substrates was also compared and is given in Figs.…”

Effect of Li2O Addition on Crystallization Behavior of CaO–Al2O3–MgO Based Inclusions

“…It is well known that non-metallic inclusions will degrade the quality of clean steel especially regarding mechanical properties and workability. Thus, numerous efforts have been made to control the composition of the non-metallic inclusions in molten steel [1][2][3][4][5][6] and the morphology of inclusions in solid phase steel. [7][8][9][10][11] The behavior of non-metallic inclusions in solid phase steel has been investigated mainly for Si-killed steel.…”