A literature review and interpretation of the properties of high-TiO2 slags

Abstract

The properties of high-TiO 2 slags are markedly different from those of many other metallurgical slags. The objective of this paper is twofold: firstly, to assemble in one document the TiO 2 slag properties, including Ti 3+ /Ti 4+ ratio, liquidus temperatures, heat capacity, density, viscosity, thermal conductivity, and electrical conductivity: all expressed in terms of temperature and composition dependency. Secondly, this paper attempts to correlate published experimentally measured data with theoretically based parameters, which will enable the application of the measured properties to wider slag compositions within the pseudobrookite-TiO 2 slag system. Keywords high-TiO 2 slag, properties.

Physicochemical properties and structure of titania-containing metallurgical slags: a review

“…Kotzé [25] introduced the electronic polarizability to calculate oxygen activity for predicting the XTi3+/XTi4+ ratio in CaO-SiO2-TiOx slags and the results of this correlation agree well with the experimental data from Tranell et al [14]. Hu et al [19] provided a semiempirical mathematical equation (Eq.…”

“…The density of FeO at 1600 °C was reported as 4.4 g/cm 3 based on the measurements done by Xin et al [86]. Therefore, the typical high-TiO2 slags have a density ranging from 3.5 to 3.7 g/cm 3 , and the higher TiO2 content results in the lower slag density [25]. For the CaO-SiO2-MgO-Al2O3-TiO2 BF type slag, Liu et al [87] reported that the density increased firstly with increasing the TiO2 content from 0 to 23 wt.%, and then decreased once the TiO2 content exceeded 23 wt.% at 1400 °C at a fixed basicity by using the dispensed drop method, while Pang et al [88] found that the density decreased with increasing TiO2 from 20 to 30 wt.% without turning point via the Archimedean principle.…”

“…The Ti 3+ /Ti 4+ ratio increases with increasing reduction degree at fixed FeO content, resulting in decreased liquidus until the Ti 3+ /Ti 4+ ratio crosses the low liquidus trough between TiO2 and Ti2O3. In practice, FeO in the slag decreases and Ti2O3 simultaneously increases as the reduction progresses, and the net effect results in the increase in liquidus temperature [25]. In the study of titania-containing BF slags, metallurgists are more concerned about the free-running temperature (also named: fusibility temperature or crystallization temperature) rather than the liquidus temperature.…”

Numerical investigation into slag solidification inside an ilmenite DC arc furnace using a finite element method approach

“…Abaqus 2017 was used as a modelling tool to resolve Equation [16] over the domain of the furnace inclusive of freeze lining, furnace sidewall, ramming, hearth, and steel shell. To accomplish this, boundary conditions have to be prescribed: 1548 (Kotzé and Pistorius, 2010) θc (°C) 50 (Zietsman, 2004) kfl (W.m-1.K-1) 1 (Zietsman, 2004) kslag (W.m-1.K-1) 1 (Zietsman, 2004) kref (W.m-1.K-1) at 500°CC [18]…”

Design of sidewall lining/cooling systems for AC or DC ilmenite smelting furnaces

“…A slag with an equivalent FeO content of 12% by mass is considered. The slag liquidus temperature is calculated based on work done separately by Kotzé (2019) considering equivalent FeO content. The slag bath temperature is considered to be 60°C above the slag liquidus temperature.…”