Electrical Conductivity of Fluoride and Oxyfluoride Molten Systems Based on FLiNaK

Abstract

The electrical conductivity of LiF–KF–NaF (FLiNaK) molten system was measured in the temperature range 480–777°C. The comparison of the obtained experimental data on molten FLiNaK with the available data for individual, double and ternary fluoride melts containing KF, NaF and LiF was carried out. The resulting dependence of electrical conductivity on molar volume of the system demonstrates that at 867°C and V_m larger than 23 cm³/mol the specific electrical conductivity is practically independent on molar volume and respectively on the molten mixture composition. The electrical conductivity of FLiNaK–CeF₃ molten systems with the cerium fluoride additions ranging from 0 to 25 mol % was measured depending on both the temperature and concentration of CeF₃. In addition, the electrical conductivity of 0.85 FLiNaK–0.15CeF₃–Li₂O molten system with Li₂O additions up to 2.3 mol % was measured. The investigation demonstrates that the addition of cerium fluoride and oxide results in a decrease of the electrical conductivity of the fluoride molten system.