The extant data for the physical properties of BOS slags and for slag systems relevant to BOS have been collated and evaluated. Data for the following physical properties have been reviewed: phase equilibria, viscosities, densities, electrical conductivities, thermal conductivities, and the surface and interfacial tension between the metal and slag. In addition, various mathematical models have been developed for the estimation of the liquidus temperature, density, viscosity, surface tension, heat capacity, and enthalpy of slags. The efficacies of these different models have been evaluated and their reliability in predicting physical property for molten BOS slags has been assessed.

Physical properties of bos slags

### Background

The proliferation of stable isotope laboratories in recent years has led to a marked increase in the routine use of stable isotope analyses in geochemical studies. This trend is likely to continue because of the development of micro-analytical techniques (e.g. laser ablation, ion microprobe, femtomole-carrier gas methods, etc.) for stable isotope analysis and the potential of these techniques to reveal the detailed sequence of thermal and fluid histories preserved in the rock record (see McKibben et al. 1998). Equilibrium isotope fractionation factors and rates of isotopic exchange form the cornerstones for the interpretation of stable isotope data from natural systems. Indeed, determination of the distribution of the stable isotopes of C-O-H-S in gases, fluids, and minerals has become a standard and extremely powerful approach in elucidating the temperatures, material fluxes, rock and fluid origins, and time scales associated with ancient and active fluid-rock interaction processes in the Earth’s crust (see Valley et al. 1986). Although the thermodynamic principles underlying isotopic fractionation behavior were developed more than fifty years ago by Urey (1947), the calibration of fractionation factors has proven to be difficult. During the last four decades, a great deal of progress has been made in determining the equilibrium fractionations of 18O/16O, D/H, 13C/12C, and 34S/32S among fluid and mineral components at high temperatures (≥400°C), both from experimental exchange studies, theoretical calculations (using vibrational spectra), semi-empirical calculations (using bond-type considerations), and empirical calibrations based on natural assemblages (see references in O’Neil 1986; Kyser 1987; Criss 1991, 1999; Chacko et al., this volume). Of these, the experimental method is the most direct because it involves the least number of a priori assumptions.

Despite the utility of the equilibrium approach in quantifying the isotopic behavior in select water-rock …

Rates and Mechanisms of Isotopic Exchange

Effects of interface kinetics, capillarity and solute diffusion on bubble growth rates in highly supersaturated liquids☆

The rate of nitrogen absorption into and desorption from liquid iron containing sulfur and/or oxygen was measured by employing a constant-volume technique with a highly sensitive pressure transducer. Critical evaluation of the results demonstrated conclusively that the chemical rate at high oxygen or sulfur contents is second order with respect to nitrogen content in the metal and probably controlled by the dissociation of the nitrogen molecule on the surface. The effect of sulfur on the rate is complex because of the influence of 1) liquid-phase mass transfer at low sulfur contents, 2) the chemical rate on vacant iron sites at intermediate sulfur contents, and 3) the rate on the adsorbed sulfur layer or the limiting rate at high sulfur contents. However, at intermediate concentrations the limiting case for the adsorption isotherm for sulfur is adhered to and the rate is inversely proportional to the sulfur concentration. For Fe-O melts the rate is inversely proportional to the oxygen content except at low oxygen levels where mass transfer affects the rate. The rate for Fe-S-O melts can be calculated reasonably well from the results for the Fe-S and Fe-0 alloys, assuming that oxygen does not effect the adsorption of sulfur andvice versa and that there is nearly complete coverage of the surface with oxygen and sulfur atoms.

The rate of absorption of nitrogen into liquid iron containing oxygen and sulfur

The densities of melts in the systems CaO-SiO2, CaO-“FeO,” “FeO”-SiO2 and in ternary melts containing 33 and 44 mole pct SiO2 have been measured from the liquidus temperature to 1600°C. Structural interpretation of melt density and expansivity has provided information on the nature of the ions present in these systems, and, in conjunction with known thermodynamic behavior, has indicated the natures of the interactions occurring among these ions. The influence of temperature, silica content andCaO/FeO ratio on the structures of ternary iron-calcium silicates is discussed.

The densities and structures of melts in the system CaO-“FeO”-SiO 2

Diffusion in Iron Oxide Melts

The interdij!usivities of iron and ox)'gen in iron oxide melts have been measured by the capillary method over the temperature range from 1 430° to 1 550°C and the composition range from r( = Fe3+ / ~" Fe ) = 0.12 to 0.42. At 1 550°C, the interdiffusivity is 4 X 10' to 5 x 105 cIll2 /sec, which is very high as com/Jared with the diffusivities of silicate slags. Activation energies for diffusion are 10.7±0.6 and 16.6±0.2kcal/mol at 1' = 0.12 and 0.33, respectively . The diffusivity decreases with increase of r. At higher Fe3+ content (r> to 0.25) , this decrease of diffusivity becomes more conspicuous. The observed reslllts arc interpreted in relation to the cOllstitution of the melts and other /Jroperties sllch as electrical condllctivity and viscosity.

https://www.jstage.jst.go.jp/article/tetsutohagane1955/54/12/54_12_1199/_pdf

Kanae Suzuki

Papers

Diffusion in Iron Oxide Melts

Diffusion in Iron Oxide Melts

Density of Iron Oxide Melt in Equilibrium with CO 2 -CO Gas Mixture

Kinetics of Nitrogen Removal from Liquid Iron

Rate of Reduction of Cr 2 O 3 by Carbon Dissolved in Liquid Fe-Cr Alloys