ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Investigation of the liquidus curve of chiolite in the system Na₃AlF₆—AIF₃

J. Vrbenská and M. Malinovský

Department of Electrotechnology, Slovak Technical University, 880 19 Bratislava

Abstract: The liquidus curve of chiolite in the system Na₃AlF₆-AlF₃ was detd. by thermal anal. in an open system. The exptl. results were submitted to thermodn. anal. The compn. and temp. of the peritectic and eutectic points are (in coordinates NaF-AlF₃): xp = 41.1 mol % AlF₃, T_p = 1006 K, x_E = 46.8 mol % AlF₃, T_E = 958 K. The exptl. results obtained in an open system indicate the existence of the compd. NaAlF₄ in the melts, decompg. at 945 K by a eutectoid reaction into chiolite and AlF₃. The existence of NaAlF₄ was also confirmed indirectly by a thermodn. anal. of the exptl. and calcd. liquidus curves. The detn. of the degree of thermal dissocn. of the chiolite anion by means of an indirect method showed that the chiolite anion dissocs. only to a minor extent, most probably according to the scheme Al₃F₁₄^5- .dblharw. AlF₆^3- + 2AlF₄^-.

Full paper in Portable Document Format: 341a47.pdf

Chemical Papers 34 (1) 47–55 (1980)