Production of the important ^99mTc medical isotope parent, molybdenum-99 (⁹⁹Mo), via the fissioning of high- and low-enriched uranium (HEU/LEU) targets followed by target dissolution in acid and solution-phase purification of ⁹⁹Mo is time-consuming, generates quantities of corrosive radioactive waste, and can result in the release of an array of radionuclides to the atmosphere. An alternative ⁹⁹Mo purification method has been devised that has the potential to alleviate many of these issues. Herein, we demonstrate the feasibility of a rapid Mo/Tc gas-phase separation from UO₂. The results indicate that volatile [⁹⁹Mo]Mo can be captured downstream of the reacted solid mixture on a column bed (trap) of alumina; the majority of the captured [⁹⁹Mo]Mo can be subsequently eluted from the alumina trap with a few milliliters of water. >1.0 × 10⁵ single pass decontamination of U and the collected [⁹⁹Mo]Mo product is demonstrated. This simple thermo-fluorination technique has the potential to provide a rapid methodology for routine ⁹⁹Mo production.