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

Phase-diagram of the system LiF-NaF-Na₂SO₄ and its thermodynamic analysis. 2. Calculation of the phase diagram according to the molecular model

P. Fellner, J. Gabčová, and J. Valtýni

Department of Inorganic Technology, Faculty of Chemical Technology, Slovak Technical University, CS-8I2 37 Bratislava

Abstract: Phase diagram of the ternary reciprocal system LiF—NaF—Na₂SO₄ was calculated according to the molecular model of molten salts. This model assumes that in an ideal molten mixture electrically neutral ionic pairs "molecules" (in this case Li⁺ • F^-, Na⁺ • F ^-, 2Li⁺ • S0₄^2-, 2Na⁺ •S0₄^2-,  and 3Na⁺ • FSO₄^3-) mix randomly. Model composition of the system, i.e. mole fractions of ionic pairs, can be calculated taking into account simul­taneous chemical equilibria among components of the molten mixture. Using the calculated model mole fractions of components, liquidus curves of pseudobinary systems LiF—Na₂SO₄ and LiF—Na₂FSO₄ and liquidus surfaces in the reciprocal ternary system LiF—NaF—Na₂SO₄ were calculated. Agreement between calculated and experimental data is good.

Full paper in Portable Document Format: 442a183.pdf

Chemical Papers 44 (2) 183–190 (1990)