Volumetric properties of liquid and solid LiF–KF mixtures

Abstract

The density of liquid mixtures of lithium and potassium fluorides with a content of 51.2 and 71.1 mol % LiF was measured using gamma-ray attenuation technique in the temperature range from liquidus to 1000–1190 K. For a mixture of near-eutectic composition (51.2 mol % LiF), the relative density change during the solid–liquid phase transition and the density in the solid state near the melting point were directly determined for the first time. The concentration dependences of the molar volume and volumetric coefficient of thermal expansion for the LiF–KF liquid system were plotted on the basis of the experimental and literature data. The obtained dependences were found to be close to the concentration dependences of the corresponding volumetric properties for ideal solutions.