Anodic oxidation — an improved technique in the chemical recovery and refinement of isotopic thallium

Abstract

The Electromagnetic Isotope Separations Program of the Oak Ridge National Laboratory has been involved in the seperation, chemical recovery and refinement of the stable isotopes of thallium since 1947. The initial interest was in obtaining chemically pure, isotopically enriched samples of each of the stable isotopes of thallium for basic physical research. Recently, the major emphasis has shifted to 203Tl which is used to produce the radiopharmaceutical isotope 201Tl. Two persistent problems in the chemistry of isotopic thallium have been the production of unoxidized, homogeneous ingots of thallium metal and the elimination of sulfur contamination in thallic oxide. The application of anodic oxidation in the chemistry has resulted in a significant reduction of the problems previously encountered as well as considerable improvement in the chemical purity of the product. The details of this procedure and a general description of all of the appropriate thallium chemistry will be presented. In addition, the generalization of the technique to the refinement of other elements will be discussed.