Thermoelectric Powers of Cells With NaF-AIF3-Al2O3 Melts

Athermodynamic description of the Peltier heat at the aluminum and the oxygen lectrode in the system NaF-AIF3-Al2O3 is given. The thermoelectric power in melts ith molar ratios nNaF/nAlF3 from 3.0 to 1.0, saturated with alumina are measured. Seebeck coefficients for molten fluoride electrolytes saturated with alumina, lectrolytes that are relevant for aluminum electrowinning electrolysis cells, are eported. The results allow determinations of Peltier heats of aluminum, oxygen and arbon electrodes in NaF-AlF3 electrolytes saturated with alumina. For molar ratios of nNaF/nAlF3 between 2.6 and 1.2, there is a Peltier heating of the aluminum cathode. his heating is in the same order of magnitude as the electrolyte Joule heat, when the urrent density is 0.7 A cm ^-2. For molar ratio nNaF/nAlF3 equal to 1.0 the Peltier effect at the aluminum electrode approaches zero. From theoretical considerations we expect a drop also for molar ratio 3.0. For the anode we report a Peltier cooling that is larger than the heat produced by the anodic overvoltage, in melts with NaF/AlF3 molar ratio between 2.6 and 1.2 saturated with alumina.