Recovery of Mo for Accelerator Production of Mo-99 Using (y,n) Reaction on Mo-100

Technical Report · Mon Sep 30 04:00:00 EDT 2013

DOI:https://doi.org/10.2172/1121046· OSTI ID:1121046

Tkac, Peter ^[1]; Vandegrift, George F. ^[1]; Nunn, Stephen D. ^[2]; Harvey, James ^[3]

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1. Argonne National Lab. (ANL), Argonne, IL (United States). Chemical Sciences and Engineering Division
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
3. NorthStar Medical Technologies, LLC, Madison, WI (United States)

Technetium-99m is a widely used radiopharmaceutical. Its parent, Mo-99, is produced worldwide to supply this important isotope. One means to produce Mo-99 is by bombarding a Mo-100 target with an electron beam from a linear accelerator; the γ/n reaction on Mo-100 produces Mo-99. After dissolving Mo-100 enriched disks in hydrogen peroxide, the solution is converted to potassium molybdate (0.2 g-Mo/mL) in 5 M KOH. After milking the Tc-99m in the TechneGen generator over a period of 7-10 days, the molybdenum solution needs to be treated to recover valuable Mo-100 for production of sintered Mo disks. However, during the production of Mo-99 by (γ, n) reaction on the Mo-100 target, several byproducts are formed. Therefore, recycling Mo will require the conversion of K₂MoO₄ in 5 M KOH solution to MoO₃ powder, and purification from other metals present in the Mo solution. The starting Mo-100 enriched material contains less than 20 mg of potassium in 1 kg of molybdenum (<20 ppm). However, after dissolving the irradiated Mo-100 target in hydrogen peroxide and converting it to K₂MoO₄ in 5 M KOH (0.2 g-Mo/mL), the solution contains about 1.8 kg of potassium per kilogram of molybdenum. The most challenging separation for this recovery step is purifying molybdenum from potassium. One requirement to facilitate the acceptance of the recycled material by the U.S. Food and Drug Administration (FDA) is that the impurities in the recycled material need to be at or below the levels present in the starting material. Therefore, the amount of potassium (K) in purified MoO₃ powder should be below 20 ppm; this will require a decontamination factor for removal of K to be ~1 × 10⁵. Such a low K-contamination level will also prevent the production of large amounts of K-42 during irradiation of Mo-100. Based on economic concerns (due to the significant cost of enriched Mo-100) recycling Mo requires the conversion of K₂MoO₄ in a 5 M KOH solution to MoO₃ powder with high Mo recovery yields (>98%).

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 1121046
• Report Number(s): ANL/CSE--13/45
• Country of Publication: United States
• Language: ENGLISH