Thermal conductivities of alkali-silicate and calcium-alkali-silicate melts

摘要

Thermal conductivities of alkali-silicate (R2O-SiO2 (R = Li, Na, K)) and calcium-alkali-silicate (CaO-R2O-SiO2 (R = Li, Na, K)) melts were evaluated by combining their thermal effusivities measured using the front-heating front-detection laser flash method with their density and specific heat capacity. Results of the evaluation revealed that the temperature-dependences of the thermal conductivities of the R2O-SiO2 and CaO-R2O-SiO2 (R = Li, Na, K) melts are small over the temperature range investigated. Moreover, the thermal conductivities of the CaO-R2O-SiO2 melts are almost equal to those of the R2O-SiO2 melts. Therefore, the network frame of the CaO-R2O-SiO2 melts can presumably become dense owing to the ion bonding between Ca2+ and the non-bridging oxygen.