Experimental Study on the Forced Rayleigh Scattering Method using CO2 Laser. (3rd Report, Measurement of Molten Single Carbonates and Their Binary And Ternary Mixtures.)

Abstract

The thermal diffusivities of molten single carbonates (Li2CO3, Na2CO3 and K2CO3) and their binary and ternary mixtures have been measured in the temperature range up to 1445K by the forced Reyleigh scattering method using a CO2 laser. The corrosion resistant material for the sample cell employed is sapphire glass plate, which was chosen through experimental evaluations. The accuracy is estimated to be ±11% to ±22%, depending on the measured salts. In comparison with the present results converted into thermal conductivity, the previous experimental data show values up to about three times larger, which may be due to the presence of convection and radiation. It is found that the thermal conductivity of molten single carbonates decreases with increasing molecular weight. It is also found that the temperature dependence of the thermal conductivity is weakly positive.