The Thermophysical Properties of Uranium Hexafluoride: Properties in the Region of Dense Gas and Liquid

Updated results of experimental studies of the thermophysical properties of uranium hexafluoride (UF 6 ) were obtained by processing the author’s data using the Origin-8 program. Updated UF 6 state para-meter values in the area of vapor−liquid equilibrium and updated data for the heat of vaporization were obtained. A physical and mathematical method for determining the critical temperature from experimental data on the boundary curve (binodal) has been developed, which made it possible to refine the critical para-meters of UF 6 : T c = 504.6 ± 0.5 K, ρ c = 1.385 ± 0.0015 g/cm 3 , P c = 45.5 ± 0.3 bar. Using P–V–T data two virial equations of state for a dense and highly compressed UF 6 gas were constructed. One of them describes the experimental data for a dense gas in the entire studied range of state parameters with a standard deviation MSD of 0.47 bar and 0.56%. The second equation provides the definition of pressure for UF 6 with MSD = 0.16 bar and 0.36% in the entire subcritical region. The data for the second virial coefficient for UF 6 in the temperature range 310–592 K were updated. The equation of state for liquid UF 6 is presented for the first time, which describes the experimental data with MSD less than 7 bar and 6% in the temperature range 453–493 K, density from ρ l at the phase boundary up to 2.9–3.1 g/cm 3 and pressures up to 200–240 bar. The description of the experimental high-pressure equipment and the methodology for conducting research and determining the parameters of the state of UF 6 is given.