Chapter 1 - Experimental and theoretical aspects of the fluorine evolution reaction on carbon anodes in molten KF-2HF

Abstract

This chapter focuses on the experimental and theoretical aspects of the fluorine evolution reaction on carbon anodes in molten KF–2CF. It begins by listing the properties and industrial uses of fluorine gas. Fluorine gas is a yellowish, poisonous and highly corrosive gas which reacts with practically all organic and inorganic substances; it reacts with all elements except helium, neon, and argon to form ionic or covalent fluorides. Because of the development of the atomic bomb and nuclear energy applications, the production of large amounts of elemental fluorine became necessary. Now, F2 gas can be considered as a necessary intermediate in uranium isotopic enrichment. The chapter reviews both experimental and theoretical aspects of the FER on carbon anode in KF–2HF. The process has been analyzed by correlating results deduced from electrochemical tests in KF–2HF.The constituents of KF–nHF melt have been identified, depending on the temperature and the HF content in KF–HF. The origin of the strong adhesion of fluorine bubbles on the surface is also discussed in the chapter. Finally, the shape of fluorine bubbles generated on horizontal carbon anodes in KF–2HF is studied from a theoretical point of view taking into account capillary forces between the electrode surface and the gas–liquid interface.