Thermal, optical and surface/interfacial properties of molten slag systems

Abstract

In modelling mass and heat transfer steps in metallurgical processes, it is important to have knowledge of the physical properties of slags, the most important among these being the surface and interfacial tensions, thermal diffusivities, optical properties and viscosities. A critical review is presented of work reported in the past two decades relating to the following properties of slag systems: (i) surface/interfacial tensions and related interfacial phenomena; (ii) thermal diffusivities and thermal conductivities; (iii) velocities and coefficients of absorption of ultrasonic waves; (iv) optical properties. A perspective for further work is also provided.

Novel High-Temperature Experimental Setup to Study Dynamic Surface Tension Phenomena in Oxide Melts

“…2−8 Detailed knowledge of those interfacial phenomena and the involved physical properties of slags is constantly accumulating, and there is a demand for reliable experimental data, including the interfacial and surface tension of the melt phases in pyrometallurgical processes. 9 In iron and steelmaking, molten slag is used for different purposes such as protection of the metal phase against atmosphere (sealing the metal from oxygen, nitrogen); removal of undesired impurities (e.g., sulfur, phosphorus), nonmetallic inclusions; reduction of heat losses; melting point reduction through optimum slag composition; low refractory interaction (e.g., protection of the lining from the arc in an Electric Arc Furnace). 10−13 Slag has a lesser density than metal and floats above the molten metal, forming an interface with the metal underneath it and an interface with the gas above it.…”

“…Interfacial phenomena are of fundamental importance for iron and steelmaking applications, since they have significant effect on the mass transfer and fluid dynamics and hence on the diverse reactions occurring across the interfaces . For decades, the importance of interfacial phenomena has been demonstrated by numerous researchers in this field. − Detailed knowledge of those interfacial phenomena and the involved physical properties of slags is constantly accumulating, and there is a demand for reliable experimental data, including the interfacial and surface tension of the melt phases in pyrometallurgical processes …”

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

“…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.…”

“…The driving force in Marangoni convection is the interface tension gradient at the steel/slag boundary. As shown, for example, by Matsushita and coauthors, 9) mainly the steel oxygen content decreases the interface tension. This oxygen content is diminished close to the SEN surface as it reacts to CO with the carbon component of the refractory.…”