A method for treating process distillate heavies produced during uranium fluoride purification is described. The heavies contain primarily uranium hexafluoride, UF.sub.6, and molybdenum oxytetrafluoride, MoOF.sub.4. The uranium hexafluoride is removed via distillation at reduced pressure leaving essentially MoOF.sub.4 containing <0.1% of residual uranium hexafluoride. This mixture is hydrolyzed in water, then treated with a solution of sodium hydroxide until a pH of at least 7.5 is reached. The precipitated sodium diuranate and sodium fluoride are removed by filtration. The filtrate is reacted with calcium chloride to precipitate the molybdenum values as calcium molybdate containing trace quantities of calcium fluoride.

A method for treating process distillate heavies produced during uranium fluoride purification is described. The heavies contain primarily uranium hexafluoride, UF.sub.6, and molybdenum oxytetrafluoride, MoOF.sub.4. The uranium hexafluoride is removed via distillation at reduced pressure leaving essentially MoOF.sub.4 containing <0.1% of residual uranium hexafluoride. This mixture is hydrolyzed in water, then treated with a solution of sodium hydroxide until a pH of at least 7.5 is reached. The precipitated sodium diuranate and sodium fluoride are removed by filtration. The filtrate is reacted with calcium chloride to precipitate the molybdenum values as calcium molybdate containing trace quantities of calcium fluoride.

A method of manufacturing particles of UO.sub.2 for a porous matrix of a target for use in the manufacture of .sup.99Mo, comprising: infiltrating a solution of uranyl nitrate into a polymer template (62); either (i) introducing an alkali chemical to the uranyl nitrate infiltrated polymer template (64), causing precipitation of uranium oxide/hydroxide, and converting the uranium oxide/hydroxide to U.sub.3O.sub.8 (68) and concurrently removing the polymer template (70), by heating the infiltrated polymer template; or (ii) converting the uranyl nitrate to U.sub.3O.sub.8 (66) and concurrently removing the polymer template (74), by heating the infiltrated polymer template; and reducing the U.sub.3O.sub.8 to UO.sub.2 via heating in a reducing atmosphere (72).

Described herein are methods for recovering uranium tetrafluoride (UF.sub.4) from uranium hexafluoride (UF.sub.6) by directly dissolving UF.sub.6 in ionic liquids and recovering UF.sub.4, which can be processed to obtain UO.sub.2 (s) or uranium metal.