富烧绿石在模拟处置条件下的浸出行为研究  

Study on Leaching Behaviors of Pyrochlore-rich Synroc Under Simulated Disposal Conditions

作　　者：张华[1] 杨建文[1] 李宝军[1] 罗上庚[1] 

机构地区：[1]中国原子能科学研究院放射化学研究所,北京102413

出　　处：《核化学与放射化学》2004年第2期65-70,共6页Journal of Nuclear and Radiochemistry

基　　金：IAEA合作资助项目(10637);国防基础研究资助项目(GFJ03F00201(3))

摘　　要：研究了包容46 8%模拟锕系废物的富烧绿石在5种模拟处置介质:纯花岗岩,花岗岩+水泥,花岗岩+Fe3O4,纯膨润土,膨润土+Fe3O4中的浸出行为。并用X射线衍射仪(XRD)和带有X射线能谱仪的扫描电镜(SEM/EDS)对浸泡后的样品表面进行了分析。实验结果显示,在模拟条件下,包容46 8%模拟锕系废物的富烧绿石的质量浸出率相当低,浸泡182d后,其质量浸出率基本保持在1×10-7g·cm-2·d-1;在含有膨润土和花岗岩+水泥介质的体系中,样品表面有新的矿相生成;膨润土和水泥介质有阻滞元素浸出的作用;Fe3O4的存在促进了元素的浸出;除钛离子在样品表面贫化外,其余5种离子Ba,U,Ca,Zr,Al在浸泡过程中呈富集态或稳定态,表明模拟地质介质可以较好地阻滞富烧绿石中元素的浸出。The leaching behavior of pyrochlore-rich synroc incorporated with 46.8% simulated actinides is studied under the following five simulated geological disposal conditions: bentonite, granite, granite+ferroferric oxide, granite+cement, and bentonite+ferroferric oxide. The mass loss rate reaches 1×10^(-7) g·cm^(-2)·d^(-1) after 182 d. That suggests that the mass loss rate of pyrochlore-rich synroc loaded with 46.8% actinide waste is very low. The surfaces of the leached specimens are analyzed by XRD, SEM/EDS. The experimental results show that two new phases form on the specimen surface of pyrochlore-rich synroc, that contains bentonite and cement, after leaching at 90 ℃ for 728 d. The bentonite and cement can retard leaching of elements from the specimen, while ferroferric oxide can speed the leaching process. Except Ti ions being depleted on the specimen, the other ions, such as U, Zr, Al, and Ca, are in a steady state, whereas Ba ions are enriched during the leaching process. These facts indicate that the simulated geological medium possesses good retarding ability for element leaching.

关 键 词：富烧绿石 模拟处置条件 浸出行为 高放废物 地质处置 

分 类 号：TL942.1[核科学技术—辐射防护及环境保护]