溶融LiCl-NaCl-AlCl<SUB>3</SUB>3成分系の電気伝導度

Abstract

Electrical conductivity of LiCl-NaCl-AlCl3 ternary melts has been measured over the composition range of less than 50 mol% AlCl3 and the temperature range of 800∼1200 K by using the conductivity cell made of quartz.\ oindentThe results obtained are summarized as follows:The conductivity of the ternary melt decreases with an increase in AlCl3 content, and in the composition range of less than about 40 mol% AlCl3, the conductivity increases with increasing ratio of the LiCl to NaCl content. The conductivity was expressed as a function of temperature and composition.By regarding the ternary melt as a reciprocal melt of (Li+, Na+||Cl−, AlCl4−), the equivalent conductivity and the activation energy for conductance were calculated. The equivalent conductivity shows a minimum value at the cationic fraction of Na+ from 0.6 to 0.9 and the anionic fraction of AlCl4− from 0.1 to 0.3. Also the equivalent conductivity showsa slight negative deviation from additivity for the cationic fraction, and a large deviation for the anionic fraction. The activation energy for conductance remains nearly constant for the cationic fraction, but exhibits a remarkable variation for the anionic fraction and shows a maximum value at about 0.2 of the anionic fraction of AlCl4−.For industrial purposes, the LiCl-NaCl-AlCl3 ternary melt may be used for the electrolytic bath of aluminum due to its high conductivity. However, it is necessary to keep the concentration of AlCl3 in the melt constant because the conductivity varies greatly with AlCl3 content, particularly in the region of low AlCl3 content.