放射性废物水泥固化体铯固化机理研究

Study on Cs^+ Solidification Mechanism in the Cement-Based Radioactive Waste Forms

采用SEM、AAS等测试方法 ,研究不同沸石掺加量、不同成型方法的沸石基碱矿渣水泥放射性废物固化体Cs+ 浸出性能和固化体微观结构 ,推理出固化体中Cs+ 的 3种持留作用 :随矿渣水化进入固化体凝胶结构中 ;被沸石颗粒吸附且被水泥胶体包裹 ;存在于固化体孔隙中 其中固化体对Cs+ 的持留作用以沸石吸附为主 ,这是因为沸石表面的部分孔隙被水泥胶体所堵塞 ,增强了固化体持留Cs+ 的能力 ,据此建立了Cs+ 固化物理模型 ,探讨了Cs+ 固化机理 对影响固化体Cs+ 浸出率的 3个主要因素 :温度、沸石颗粒表面孔隙、固化体孔隙率进行了分析 ,进而合理解释了固化体中Cs+

By the techniques of SEM and AAS, the leaching property and microstructure of radioactive waste with various zeolite content and different forming methods are studied. Three kinds of retaining Cs + actions in zeolite added alkali activated slag cement radioactive wastes are discovered: combined with the gel structure in the waste solid form, absorbed in the zeolite particles enwrapped with cement gel, and existed in the capillaries and gels, on which the activity of solid form retaining Cs + plays an important role because of zeolite surface blocked up with cement gel. The physical model of Cs + solidification is established. Further more, the solidification mechanism of Cs + which could give a reasonable explainati on the Cs + leaching behaviors of the solidification waste forms is discussed on the basis of analysis on factors affecting Cs + leaching rate of temperature, porosity of zeolite particles and waste solid form.