Manganese, technetium and rhenium

Rhenium Solubility in Borosilicate Nuclear Waste Glass: Implications for the Processing and Immobilization of Technetium-99

“…Rhenium has been the preferred nonradioactive 99 Tc surrogate material over other candidates such as Mn or W, because of rhenium’s similarities to technetium in chemistry, ionic size, speciation in glass, volatility from glass, and other aspects . Although many groups have reported divergent behavior due to differences in the reduction potentials of Re 7+ and Tc 7+ , − the chemistry of the two elements is very similar when in the same oxidation state. In other words, while Re is not a perfect surrogate for Tc due to the differences in reduction potentials, Re 4+ is a good surrogate for Tc 4+ and Re 7+ is a good surrogate for Tc 7+ .…”

“…Consequently, the most important Tc species in Hanford LAW glass is hypothesized to be TcO 4 – . The similarities between ReO 4 – and TcO 4 – overwhelmingly argue for its utility in obtaining preliminary data in a nonradioactive environment that can later be corroborated with Tc. , Moreover, Re 7+ and Tc 7+ have the same volatility issues in glass processing, and no other surrogate element has been found that can duplicate this important aspect. Additionally, rhenium compounds should be chemically similar to those expected for technetium in LAW simulants (KTcO 4 ) as well as those in liquid (CsTcO 4 , NaTcO 4 , and KTcO 4 ) and vapor (Tc 2 O 7 and TcO 3 (OH)) phases during vitrification .…”