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

Cryolite Corner of the Phase Diagram of the Ternary System NaF—AIF₃—KF

J. Gabčová, M. Marko, and P. Fellner

Department of Inorganic Technology, Faculty of Chemical Technology, Slovak Technical University, SK-812 37 Bratislava

Abstract: Experimental data on solid-liquid phase equilibria of sodium cryolite corner of the ternary system NaF-AIF₃-KF are presented. Composition was changed in the following range: x(NaF)/mole % = 40-80; x(AIF₃)/mole % = 20-40; x (KF)/mole % = 0-20. A formal model of molten cryolite-based mixtures was used for description of the obtained experimental data. The model assumes that all KF reacts with AIF₃ under formation of K₃AIF₆ and all remaining AIF₃ reacts with sodium cryolite under formation of NaAIF₄. For the temperature of primary crystallization it holds   θ_tpc/°C = 1009.17 - 235.44 y(K₃AlF₆) - 10.95 y(NaAIF₄) - 638.91 [y(NaAIF₄)]⁴ This equation holds in the following range of compositions: 25-35 mole % AIF₃, 0-20 mole % KF. Standard deviation equals 1.86 K.

Full paper in Portable Document Format: 491a13.pdf

Chemical Papers 49 (1) 13–15 (1995)