Simple Method for Estimating the Electrical Conductivity of Oxide Melts with Optical Basicity
- PDF / 286,794 Bytes
- 6 Pages / 593.972 x 792 pts Page_size
- 75 Downloads / 196 Views
I.
INTRODUCTION
IN a high-temperature metallurgical system, the electrical conductivity of molten slag is an important physical property that plays a prominent role in modeling and operating the electric smelting furnace. However, because the electrical conductivity measurements are time consuming and require considerable expertise, there is an obvious industrial need of models for the rapid calculation of electrical conductivity from the chemical composition and temperature, which are readily available. Because the electrical conductivity includes two parts, ionic conductance and electronic conductance, the estimation of electrical conductivity for these systems containing both of them will be difficult. The method provided in this article can only be applied to the system without electronic conductance. For these systems, the existing models are lacking.[1,2] These models all involve a numerical fit of the electrical conductivity to the chemical composition and temperature, and the melt structures are not taken into account. Mills[3] suggested that it may be possible to use the optical basicity to represent the structure, which could be used to calculate the structurally dependent properties such as the viscosity, the electrical conductivity, and the expansion coefficient of molten slags. Now it has been proved that the optical basicity has a deep relationship with many physiochemical properties of liquid slag, such as sulfide capacities,[4] phosphide capacities of metallurgical slag,[5] activity of P2O5,[6] GUO-HUA ZHANG, PhD Graduate Student, is with the School of Metallurgical and Ecological Engineering, University of Science & Technology Beijing, Beijing, P.R. China, and KUO-CHIH CHOU, Professor, is with the University of Science & Technology Beijing, Beijing, P.R. China, and the Metallurgical and Materials Processing Laboratory, Shanghai University, Shanghai 20072, P.R. China. Contact e-mail: [email protected] Manuscript submitted May 26, 2009. Article published online September 11, 2009. METALLURGICAL AND MATERIALS TRANSACTIONS B
activity of CaO and Na2O,[7] as well as some other physical properties, such as viscosity[8] and density.[9] Thus, the objective of this study is to find the relationship between the electrical conductivity and optical basicity K.
II.
MODEL
A. Model Description A reasonable electrical conductivity model should take into account both influences of the composition and temperature. The optical basicity is composition dependent. Considering that the ionic conductance is related to a thermal activation process, the relationship between it and temperature can be described by the Arrhenius Law, in which the activation energy is assumed to be a linear function of optical basicity for simplicity. Therefore, the model can be expressed as follows: ln j ¼ ln A B=ðRTÞ
½1
where A is a constant, B is the activation energy that is a function of the optical basicity, R is the universal gas constant, and T is the absolute temperature. The model should consider the effect of Al2O3, which exhibits as a
Data Loading...
