CHARACTERIZATION OF THE PHYSICOCHEMICAL BEHAVIOR OF WATER IN THE KF.2HF WATER SYSTEM BY MEANS OF CONDUCTANCE AND VISCOSITY MEASUREMENTS/

The solvate KF.2HF is used in the molten state at 85 degrees C for the production of F-2. Water can be present in small quantities in the HF feed for this process and causes various complications such as corros ion of cell components and undesirable formation of F2O. The work desc ribed in this paper examines the effects of presence of H2O in KF.2HF melts in a comprehensive way over a wide range of mole fractions of wa ter in the KF.2HF system. The conductivity, viscosity and Walden produ ct are evaluated together with the determination of the density, to pr ovide information on selective solvation, speciation and acidity in th e system, as well as volumetric deviations of additivity in the thermo dynamic properties of the system. Complete primary hydration of the io nic species appears to be reached at a mole fraction of water around 0 .88, i.e. 7 water moles per mole of KF.2HF.