Dry-Distillation of Iodine-131 from Several Tellurium Compounds

Abstract

Several Te compounds including a new Te oxide Te5O11 were subjected to dry-distillation after reactor irradiation in order to overcome the difficulties accompanying the ordinary dry-distillation from TeO2. The release of 131I from Te5O11 was examined as function of distillation temperature and the thermal behavior of 131I released was studied by means of thermochromatography. For comparison, the 131I release from other Te compounds such as H5TeO6, (H2TeO4) n , and TeO3 was also studied. The compounds studied in this work were found to release 131I rapidly at temperatures lower than employed in the ordinary dry-distillation of 131I from TeO2, thus obviating all risk of contaminating the final products with Te vaporizing at higher temperatures. The rapid release of 131I was concluded to be caused by thermal decomposition of the compounds studied. In an attempt to prepare a “dry source” of 131I, 131I dry-distilled from Te5O11 was adsorbed on Molecular Sieve, and the release of 131I from the Molecular Sieve was similarly studied.