Interaction between Iron Fluoride and Molten FLiBe

Abstract

The equilibrium potentials of iron in a LiF-BeF2-FeF2 melt were measured using the EMF method and were dependent upon the temperature and iron fluoride concentrations. The empirical equations for the isotherms and equilibrium polytherms of the iron fluoride concentration were obtained. The cathode polarization of iron fluoride in the molten mixture of lithium and beryllium fluoride was measured using the current switch off method from the stationary state. It was found that in the studied temperature and concentration ranges of iron fluoride in the LiF-BeF2 electrolyte, the valence state of iron in the melt is mainly +2. According to the experimental values of the equilibrium potentials of the iron electrode in the LiF-BeF2-FeF2 melt, the conditional standard potentials of iron were calculated relative to the fluoride reference electrode in the molten mixture of lithium and beryllium fluoride. The conditional standard values of the Gibbs energy change were calculated at the formation of iron difluoride from the element in the form of dilute solutions, as were the thermodynamic values (enthalpy and entropy) when iron difluoride was mixed with LiF-BeF2.

Interaction Between Uranium Trifluoride and the Mixture of Lithium and Beryllium Fluorides

“…1) is described in detail elsewhere. 37,38 Table III presents the results of the performed measurements. Average arithmetic values of the galvanic element EMF (Eq.…”

“…There is a vast literature data on the measurements of the kind using Li/Li+ and Са/Са2 + dynamic reference electrodes to study the processes in chloride melts, 33,34 as well as К/К + and Ве/Ве 2+ reference electrodes are used to analyze fluoride salts. 28,29,[35][36][37][38] Figure 3 presents a schematic of the electrochemical cell that was used for EMF measurements of the galvanic element.…”

Electrochemical Behavior of Chromium Difluoride in Molten Lithium and Beryllium Fluoride Mixtures

“…It is shown that the alteration of the conditional standard potential is compatible with the published literature data. 34 If any single form of chromium cations valence dominates in the melt, we consider the standard state to express the concentration dependence of the cations activity and the equilibrium electrode potentials 36 of the galvanic cell (2). The fluorine ions molar concentration in the fluoride melt equals to unity, therefore, we can conditionally assume that the activity of fluorine ions is equal to one, regardless of the temperature.…”

“…A detailed description of the electrolytic cell used in the present research is presented elsewhere. 34 Metallic Cr was added to the electrolyte using the anode dissolution to maintain the desired chromium ions concentration. The amount of electricity passed was calculated from the currenttime dependence and controlled by the inductively coupled plasma mass spectrometry (by the atomic-absorption method using an Optical emission spectrometer with the inductively bound plasma (Perkin Elmer OPTIMA 4300 DV, USA).…”

Electrochemical Technology for New Materials Synthesis and Reprocessing

“…The paper by Arkhipov et al [6] provides thermodynamic data for the metal/FLiBe system. These data provide an understanding of the metal behavior in fluoride melts and provide practical guidance when choosing appropriate construction materials to be used in molten salt technologies, as well as for the electrolytic production of metals and the design of molten salt reactors.…”