PREPARATION OF LOW OXYGEN CONTENT YTTRIUM FLUORIDE

摘要

The purpose of this investigation was to determine the optimum conditions for the formation of very low oxygen content yttrium fluoride.nVarious methods of preparing a very low oxygen content yttrium fluoride are presented. Since the chemical properties of yttrium are quite similar to those of the rare earths, yttrium was used in these studies with the object in mind that the processing conditions would probably be applicable to the rare earths.nYttrium fluoride was formed by hydrofluorinating various yttrium compounds with gaseous anhydrous hydrofluoric acid. The compounds used for these hydrofluorinations were yttrium oxide, hydrated yttrium fluoride, yttrium oxalate, yttrium chloride, yttrium nitrate, yttrium sulfate, and yttrium sulfide. The effects of time and temperature, oxalate ignition temperature, particle size, and hydrofluoric acid purity on the conversion of yttrium compounds to yttrium fluoride were also studied.nThe yttrium fluoride purification methods studied were molten fluoride hydrofluorination, vacuum distillation and inert gas sparging, all of which were carried out above the melting point of yttrium fluoride.