Recovery, recycling and re-irradiation of enriched 104Ru metal targets for cost effective production of 105Rh

• Published in: Applied radiation and isotopes 2021-10, Vol.176, p.109847-109847, Article 109847
• Main Authors: Okoye, Nkemakonam C., Phelps, Tim E., Charles, Anster, McCormick, Joshua B., Wycoff, Donald E., Lydon, John D., Embree, Mary F., Guthrie, James, Kelley, Steven P., Barnes, Charles L., Ketring, Alan R., Hennkens, Heather M., Jurisson, Silvia S.
• Format: Article
• Language: English
• Subjects: 105Rh production; Conversion to 104Ru metal; Enriched 104Ru; H2 reduction; Neutron re-irradiation of recycled 104Ru; Target recovery/recycling
• ISSN: 0969-8043; 1872-9800
• DOI: 10.1016/j.apradiso.2021.109847

Rhodium-105 (0.567 MeV β-, 319 keV γ, 35.4 h half-life) was produced by neutron irradiation of enriched 104Ru (>99%) over multiple decades. A method is reported to recover the previously irradiated 104Ru (trapped in HCl as RuO42−) as the metal. The 104Ru was recovered in >93% yield and >98% enrichment. Neutron re-irradiation of the recycled 104Ru produced 105Rh, which was successfully radiolabeled with tetrathioethers in high yield. This recovery and recycling method for enriched 104Ru makes 105Rh production and utilization economical. •Neutron irradiated 104Ru recovered from 3 M HCl solution as 104RuO4.•104RuO4 converted to 104RuCl3·xH2O and then to 104Ru metal directly under H2.•104RuO4 converted to 104RuCl3·xH2O and then to RuO2 in air and to 104Ru metal under H2.•Greater than 93% recovery and >98% enrichment of 104Ru metal.•Neutron re-irradiation of recycled 104Ru produced 105Rh, which labeled standard tetrathioethers in high yield.