Thermal Conductivity of Molten Slags: A Review of Measurement Techniques and Discussion Based on Microstructural Analysis

Abstract

In order to properly interpret the thermal conductivity of molten silicate slags, several different measurement methods are briefly reviewed, along with a discussion as to their respective advantages and limitations. In addition, a large number of thermal conductivity values measured by these methods are assessed, in order to evaluate their dependence on composition and temperature. The behavior of the thermal conductivity of molten silicate slags was found to show good agreement with well-focused analyses into its microstructure. Moreover, with an improved understanding of the microstructure of silicate slags, there is an apparent co-relation between thermophysical properties such as thermal conductivity, viscosity, and so forth.KEY WORDS: thermal conductivity; molten slag; silicate; hot-wire method; laser flash method.

Thermal Conductivity Measurement of the Molten Oxide System in High Temperature

“…In steady-state method, thermal conductivity is determined by the temperature profile across a sample contacting directly with a heat source [15]. However, steady-state method requires a relatively long measurement time in order to obtain the steady state of thermal profile across the sample [18]. In addition, during the measurement, contribution of radiation and convection becomes significant due to the long measurement time.…”

“…Since the thermal conductivity is measured within only 12 ms, front-heating front detection technique does not consider the additional process for distinguishing radiation effect from observed thermal conductivity data. However, although the front heating-front detection laser flash method has the merit of simple procedure and easy data processing, [34] the effect of radiation on thermal conductivity measurement is still controversial, especially at high temperature [18]. The three different laser flash methods, namely, conventional, three-layered and front heating-front detection laser flash method, have been adopted for the measurement of thermal conductivity, and more details can be found elsewhere [18].…”

“…At higher temperature of the transparent molten oxide system, more than 90% of heat is transferred by the radiation conduction. On the other hand, thermal conductivity by electron is insignificant in the molten oxide system as long as the composition of transition metallic oxide does not exceed 70% [15,18].…”

A comprehensive characterization on the structural and thermophysical properties of sintered ore particles toward waste heat recovery applications

“…The quality of these computer simulation studies depends on the reliability of the input data, especially the thermophysical properties. As the most important property for heat transfer modeling, the thermal conductivity of SOPs and related materials has been measured by a variety of methods [16]. The thermal conductivity of dense pure and reduced iron ore agglomerates and nonfired pellets were measured using the laser flash method (LFM) [17].…”

Thermal Conductivity of Solidified Industrial Copper Matte and Fayalite Slag

“…Thus, due to the heat transfer dependence on phonon vibration, thermal conductivity will be influenced by the number of covalent bonds (together with ionic). The thermal conductivity of fayalite slag at liquidus temperature increases with the SiO2 content of the slag [18,19].…”