Coprecipitation of radioactive technetium with hydroxides has been studied for the purpose of the management of the high level waste from the nuclear fuel reprocessing. Pertechnetate ion was reduced to Tc(IV) by ferrous ion (Fe
2+), and then coprecipitated with Fe(OH)
2 (I) as TcO
2. The pH of nitric acid solution containing TcO
4- was adjusted to 1.0 with NaOH, and TcO
2 was precipitated by reducing coprecipitants i.e. (I), Fe(OH)
2-Zr(OH)
4 (II), Fe(OH)
2-Si(OH)
4 (III) and Fe(OH)
2-Zr(OH)
4-Si(OH)
4 (IV). Pertechnetate ion quantitatively coprecipitates under the conditions: Fe
2+>3.6×10
-3M; pH=6-12 for (I), pH=4.2-12 for (II), pH=8-12 for (III) and pH=6-12 for (IV). The presence of excess Fe
2+ prevents the dissolution owing to air-oxidation of TcO
2 coprecipitated. Pertechnetate ion can be also removed from the waste solution by boththe ferrite precipitation method and the iron powder precipitation method.
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