ABSTRACT

Fluorination is the process in which a metal fluoride is obtained by dry methods. Fluorides in the molten state play an important role in the preparation of certain metals by fused salt electrolysis, for example, aluminum from Al2O3—Na3AlF6 bath. The unit process fluorination is very similar to chlorination with respect to the methods and equipment. Fluorine is a light canary yellow gas which condenses to a clear yellow liquid boiling at—187°C. Alkali hydrogen fluorides are crystalline solids that contain HF in chemical combination and readily release it on heating. Ammonium hydrogen fluoride is used for converting pure oxides or hydroxides into their corresponding fluorides for reduction to metals. The reaction takes place in two steps: in the first step a double flouride is formed which is decomposed at a higher temperature in the second step. Uranium hexafluoride is the only gaseous compound of uranium and therefore most suitable for use in the gas diffusion process for enrichment of the isotope U235.