Takao Koichiro, Mori Takahiro, Kubo Mayuu, Uehara Akihiro, Ikeda Yasuhisa
Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 N1-32, O-okayama, Meguro-ku, 152-8550 Tokyo, Japan.
Laboratory for Advanced Nuclear Energy, Institute of Innovative Research, Tokyo Institute of Technology, 2-12-1 N1-32, O-okayama, Meguro-ku, 152-8550 Tokyo, Japan.
J Hazard Mater. 2019 Jan 15;362:368-374. doi: 10.1016/j.jhazmat.2018.09.042. Epub 2018 Sep 14.
Here, we show unexpected and significant elution behavior of various elements from simulated nuclear waste glass (NWG) in ∼10° mol dm acidic solutions below 100 °C, where a borosilicate-based glass matrix has been believed to be chemically durable. Most elements like glass main components (Li, B, Na, Ca, Al, and Zn, but except for Si) and simulated radionuclides (Rb, Cs, Sr, Ba, Se, Te, Mn, Pd, Mo, rare earths, Cr, Fe, and Ni) were remarkably eluted from the simulated NWG in ∼10° M HNO aq with Cl at 90 °C. Especially, the elution of Pd is governed by its coordination chemistry including a redox reaction, because Pd(0) present in the simulated NWG has to be oxidized to Pd which forms [PdCl] for its dissolution. While Zr in simulated NWG is sparingly eluted even in this treatment, its elution actually proceeds in 1-3 M HSO aq at 90 °C thanks to strong coordination of Zr(IV) with SO. Through design and optimization of the leaching conditions, a protocol of the wet chemical process to retrieve the radionuclides from simulated NWG has been proposed and demonstrated.
在此，我们展示了在100°C以下约10°mol·dm的酸性溶液中，各种元素从模拟核废料玻璃（NWG）中呈现出意想不到的显著洗脱行为，而在此之前，人们一直认为硼硅酸盐基玻璃基体具有化学耐久性。大多数元素，如玻璃主要成分（锂、硼、钠、钙、铝和锌，但硅除外）以及模拟放射性核素（铷、铯、锶、钡、硒、碲、锰、钯、钼、稀土元素、铬、铁和镍），在90°C下的约10°M硝酸水溶液中，含有氯离子时，会从模拟NWG中显著洗脱出来。特别是，钯的洗脱受其配位化学（包括氧化还原反应）的控制，因为模拟NWG中存在的零价钯必须被氧化为钯，形成[PdCl]才能溶解。虽然模拟NWG中的锆即使在这种处理下也很少被洗脱，但由于锆（IV）与硫酸根的强配位作用，其洗脱实际上在90°C的1 - 3M硫酸水溶液中进行。通过设计和优化浸出条件，已经提出并证明了一种从模拟NWG中回收放射性核素的湿化学过程方案。
