The presence of Technetium-99, an undesirable radioelement in process raffinate makes it a unique challenge to safely dispose of nuclear waste. With a half-life of 2.13 � 105 years, and an affinity to form highly mobile pertechnetate species, TcO4-, Tc-99 is considered a long-term hazard in nuclear waste disposal. Furthermore, the vitrification of certain wastes such as the Hanford tank waste containing Tc-99 is very problematic because of disproportionation and the resulting technetium volatilization at the conditions of melter operation.  Technetium separation and stabilization by the fabrication of durable crystalline Tc waste-forms as a means of reducing the burden on a geological repository requires technetium to be removed from problematic waste-streams.  This paper will give an assessment of the current knowledge of the ligands-based solvent extraction processes developed over the last 20 years for the selective and efficient removal of technetium from different waste-streams and will provide strategies for its immobilization.

Summary of technetium-99 extraction from different waste streams

243rd National Meeting (2012)

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