R_2O-CaO-SiO_2(R=Li, Na, K)スラグの熱伝導度とその推算(高温プロセス基盤技術)

概要

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Thermal conductivities of Li_2O-CaO-SiO_2, K_2O-CaO-SiO_2 and 37CaO-63SiO_2 slags have been determined using the non-stationary hot wire method over a wide temperature range between room temperature and 1823K to propose a prediction equation for thermal conductivities of R_2O-CaO-SiO_2 slag melts, where R represents Li, Na and K. The temperature coefficients of thermal conductivities for all the samples were negative in the liquid state. The thermal conductivities of slags having the same SiO_2 concentration, i.e., the same NBO/T (number of non-briging oxygens per tetrahedrally coordinated atom), decreased by replacement of CaO with R_2O but took almost the same value at their liquidus temperatures (T_L), irrespective of the (%R_2O)/(%CaO) ratio. Furthermore, plotting the thermal conductivities against T/T_L (temperature normalised by T_L) shows that the thermal conductivities for the melts are not dependent upon the (%R_2O)/(%CaO) ratio within experimental scatter as long as the SiO_2 concentration is kept constant. On the basis of this finding, an empirical prediction equation has been proposed for thermal conductivities of R_2O-CaO-SiO_2 melts.
2007-06-01