Interfacial tension effects on slag—metal reactions

Abstract

Dynamic X-ray imaging of a metal droplet in a slag phase is an elegant way to monitor the rate of the interfacial reactions. In an attempt to follow the kinetics of dephosphorization, the changes in the shape of the sessile drop of molten iron with 0.1 wt% P immersed in a slag kept in MgO crucibles were recorded as a function of time. The slag had an initial composition 40 wt% CaO, 30 wt% SiO 2 and 30 wt% Fe 2 O 3 . While in a set of runs, solid iron was added to the molten slag, the sequence was reversed in others, where a pellet of the slag was added to the molten iron. In the former case, it was found that after 10 s, the drop flattened and the contact angle, θ was well below 90 • , indicating a significant increase in the contact area. Beyond 250 s, the contact angle showed a gradual increase. In the second series, where the slag was added to the metal, the contact angle remained high throughout the dephosphorization reaction, indicating a rapid mass transfer of phosphorus.Similar application in the field of copper metallurgy, where the transfer of arsenic and antimony from copper metal to molten Na 2 CO 3 was studied, confirm that this technique is very useful in understanding the mechanisms of the slag-metal reactions.

Some Investigations into the Dynamic Mass Transfer at the Slag–Metal Interface Using Sulfur: Concept of Interfacial Velocity

“…[1][2][3][4][5] Interfacial phenomena studies mainly focusing on Marangoni forces and interfacial tensions have also been dealt with extensively. [6][7][8][9][10] The potential drive for this extensive research is the importance of interfacial reactions in metallurgical process occurring during metal refining, degasification process, and slag entrapment. However, some issues with respect to the interfacial properties need to be addressed, viz.…”

“…The furnace had also been calibrated earlier with other metals like copper, nickel and iron [8] Cu : r Nm…”

Density, Surface Tension, and Viscosity of CMSX-4® Superalloy

“…The surface tension of the alloy was measured in a flow of purified inert gas by the sessile-drop method. Two different techniques were applied: the X-ray sessile-drop [5] and the large-pinned drop [7]. The experiments were performed from the liquidus temperature and above: the CMSX-4 liquidus temperature is T l = 1654.5 ± 4 K [11].…”

“…The measurement of the density was performed by a levitation diffusivity technique, while that of the viscosity with an oscillating cup viscosimeter. The present study was carried out based on the technique and knowledge acquired from the previous experiments [5][6][7]. CMSX-4 is a nickel-based superalloy widely used in the aerospace industry for turbine blades.…”

Analysis of the source of dynamic interfacial phenomena during reaction between metal droplets and slag

“…[6] The phenomena also occur in systems other than liquid iron/ steel and slag. Some investigators reported the phenomena in reactions between liquid copper and molten Na 2 CO 3 [8] or during reactions between Cu-Ni-Al alloy with Li 2 O-Al 2 O 3 -SiO 2 slag. [9] The phenomena described are well observed and recognized; however, they are not fully understood.…”