Surface Tension Measurements of Calcia-Alumina Slags: A Comparison of Dynamic Methods

Abstract

The surface tension of oxide melts is difficult to measure. Even for binary slags with a low degree of polymerisation such as calcia-alumina, there seems no benchmark value for the surface tension available. Published data exhibit considerable scatter even for similar compositions which prevents to build a reliable and consistent database of frequently used physical properties. This study presents an attempt to use three different measurement techniques in the same hightemperature furnace to obtain the surface tension of a binary calcia-alumina slag close to eutectic composition, namely the drop weight method, the pendant drop method, and, for the first time, the oscillating jet method (for circular and elliptic jets) as a function of temperature. The methods used in the present context are explained, and the experimental results evaluated with respect to previously published data. A consistent and coherent trend is observed when the drop weight and the oscillating jet methods are compared.

Slag Properties in the Primary Production Process of Mn-Ferroalloys

“…However, studies on slags in steel production have shown that surface tension of most multicomponent slags lies in the range from 0.30 to 0.70 N/m. [99][100][101] Bublik et al 102 have found that surface tension of slags corresponding to FeMn and SiMn production are 0.65 and 0.50 N/m, respectively. IV.…”

Surface ionic coordination of Al2O3–CaO–based molten slag induced by structural relaxation

“…The surface tension of pure Al 2 O 3 and CaO melts is measured or estimated as between 600–700 mN $$/$$ m at their melting points 21–22 . Taking account of its negative temperature dependence, it is interpreted that the surface tension of the Al 2 O 3 –CaO mixture 17–20 is lower than those of pure Al 2 O 3 and CaO melts (estimated as 700–800 mN/m at 1873 K, and therefore shows a minimum at an intermediate composition 19 . Additionally, it has been reported that the surface tension of the Al 2 O 3 ‐CaO‐MgO melts with fixed MgO mass content shows the minimum at an intermediate composition against the Al 2 O 3 /CaO mass ratio 23 .…”

Mirco-level Insight into the Surface Tension-structure Relationship of Molten CaO–MgO–SiO₂–Fe<i>_x</i>O–P₂O₅ Slags

“…To control metallurgical behavior in smelting process, numerous studies on the surface tension of slag have been carried out. [3][4][5][6] Yuan et al 7) considered that cation potential (z/r) is closely related to surface tension, and a larger value of z/r in the SiO 2 -FeO-MgO-CaO system could enhance…”