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

Thermodynamic Analysis of the Molten System KF—K₂Mo0₄—B₂0₃

O. Patarák, V. Daněk, M. Chrenková, and A. Silný

Institute of Inorganic Chemistry, Slovak Academy of Sciences, SK-842 36 Bratislava

Abstract: The thermodynamically consistent phase diagram of the ternary system KF-K₂Mo0₄—B₂0₃ up to 30 mole % B₂O₃ was calculated using the coupled analysis of the thermodynamic and phase diagram data.In the system KF-K₂Mo0₄—B₂0₃ the intermediate compound K₃FMoO₄ melting congruently at 751°C is formed. This compound divides the binary system KF-K₂MoO₄ into two simple eutectic ones the coordinates of which are: 29.4 mole % K₂MoO₄, 717.7°C, and 56.9 mole % K₂MoO₄, 747.4°C. In the binary system KF-B₂O₃ the liquidus curve decreases monotonically with increasing content of B₂O₃. The inflexion point was found in the course of the liquidus curve of K₂MoO4 in the binary system K₂Mo0₄—B₂0₃. The strong positive deviation from ideal behaviour was ascribed to the possible formation of heteropolyanions [BMo₆O₂₄]^9- in the melt.In the investigated concentration range of the ternary system one eutectic point has been found the coordinates of which are: 57 mole % KF, 24 mole % K₂MoO₄, 19 mole % B₂O₃, and θ_e = 682°C. The standard deviation of approximation in the calculated ternary phase diagram is +/- 5.2°C.

Full paper in Portable Document Format: 515a263.pdf

Chemical Papers 51 (5) 263–267 (1997)