Thermal Conductivity Measurements and Prediction for Molten Silicate Slags with Dispersing CaO Phases

Abstract

The present work has aimed to confirm experimentally the applicability of the following prediction equation for thermal conductivity to molten silicate slags with dispersing CaO phase:
[Equation]
where λ_eff is the effective thermal conductivity of the whole system, λ₀ and λ₁ are the thermal conductivities of the matrix and dispersing phases, respectively, and f₀ is the volume fraction of the matrix phase. The above equation was conventionally proposed to predict thermal conductivities for two-phase systems with dispersing phases such as composite materials, and thus it was required to investigate its applicability to liquid samples with dispersing solid phases. First, thermal conductivity measurements were made at room temperature on silicone oil having polyethylene dispersion and gel and paraffin having alumina dispersion as well as the single phases of the constituent substances. Likewise, thermal conductivities were also measured on molten CaO–3mass%SiO₂–37mass%Al₂O₃ slags having CaO dispersion at 1743K. These measurements have confirmed that the prediction equation applies to the two-phase systems with dispersing phases used in the present work. Thus, it is likely that thermal conductivities of molten silicate slags with dispersing CaO phase can be predicted from the equation using the thermal conductivities of CaO and molten slags and the volume fraction of CaO at a given temperature as long as no percolation of CaO occurs.