ELECTRICAL-CONDUCTIVITY OF THE MOLTEN CRYOLITE-BASED TERNARY MIXTURESNA3ALF6-AL2O3-CAF2 AND NA3ALF6-AL2O3-MGF2

The electrical conductivity for several compositions in the ternary sy stems Na3AlF6-Al2O3-CaF2 and Na3AlF6-Al2O3-MgF2 and in the quarternary system Na3AlF6-Al2O3-CaF2-MgF2 was measured using a pyrolytic boron n itride tube-type cell with a cell constant of about 40 cm-1. The resul ts were fitted to the following equation, kappa/S cm-1 = 7.22 exp(-120 4.3/T)-2.53[Al2O3] -0.76[CaF2]-1.07[MgF2] -1.80[Al2O3][CaF2]-2.59[Al2O 3][MgF2] where T is the temperature in K and the brackets is the mole fractions of the given components. The standard deviation was found to be 0.018 S cm-1. The equation is expected to be valid in the composit ion range, Na3AlF6 with (0-26) mol% CaF2, (0-35) mol% MgF2 and (0-satu ration) mol% Al2O3. The temperature range is from 940 to about 1050-de grees-C.