Immobilization of Rhenium as a Technetium Surrogate in Aluminum Iron Phosphate Glass

Abstract

Samples of sodium aluminum iron phosphate glass were synthesized containing rhenium as a surrogate of technetium from radioactive waste. The phase composition, structure and water resistance of the obtained glasses were investigated. It was shown that the samples with the rhenium oxide inclusion up to 2.88 wt % are X-ray amorphous and homogeneous, and their anionic motif corresponds to the glassy one. It was found that the oxidation state of rhenium in the obtained glasses is Re(VII), and 97% of iron is in the form of Fe(III) and 3% in the form of Fe(II). The glass was established to be highly resistant to leaching at 90°C. The rate of Re leaching from glasses in accordance with the international product consistency test (PCT) and the semi-dynamic test of State Standard GOST R 52126-2003 is no more than 6 × 10–6 and 3 × 10–6 g/(cm2 day), respectively.