Electrochemical Characterization of Low-Temperature Molten Mixture Systems Suitable as an Innovation in Aluminum Technology

The electrical conductivity has been measured and described for low-temperature NaF-KF-AlF3 mixtures by the electrochemical impedance spectroscopy. The temperature dependence was investigated in the range from the temperature of primary crystallization to about (80-100)degrees C overheat, i.e. from 655 degrees C to 875 degrees C. The electrolytes with the molar ratios in the range from 1.2 to 1.5 (with a step of 0.1) have been investigated. The electrical conductivity has been measured for four different concentrations of NaF (50, 40, 20 and 10%) in the mixture NaF-KF-AlF3 at all molar ratios. The electrical conductivity was measured using a tube-type cell with stationary electrodes applying AC-techniques with a sine wave signal in the high frequency range. The values of electrical conductivity decreased with lower MRs and with lower temperatures. Higher addition of NaF led to higher electrical conductivity. The concentration and temperature dependency of the electrical conductivity was described by the regression equation. The equation is valid throughout the studied concentration and temperature range. (C) 2018 The Electrochemical Society.