SiO2和B2O3含量对模拟高放废物玻璃结构的影响

硼硅酸盐玻璃具有特别高的化学稳定性、较好的热稳定性、较大的放射性废物包容量等优点，被广泛作为固化高放废液的基础玻璃料。废物玻璃固化体的结构与其组成存在一定的内在依存关系，它将对废物玻璃的性质产生影响。以组分含量作为变量，所引起的废物玻璃固化体的某些结构特征的变化，是探索影响高放废物玻璃固化体性能的内在线索。为了获取废物玻璃组分含量对其结构特征参数（非桥氧键数）的影响规律，以对废物玻璃固化体的性能进行估计，进而指导设计高效处理高放废液的玻璃固化体配方，以某模拟高放废物玻璃固化体的配方为基础，通过改变其中SiO₂和B₂O₃含量制备一系列的废物玻璃样品，并进一步采用拉曼光谱法对废物玻璃的硅酸盐网络结构单元（Qn，Q和n分别代表四面体单元和每个四面体结构单元所具有的桥氧键数）进行分析，讨论SiO₂和B₂O₃含量对此废物玻璃固化体网络结构的影响。结果表明：随着SiO₂含量（SiO₂的质量与剩余氧化物质量的比值）由0.721增加到1.037，废物玻璃固化体中桥氧键的比例随之而增多，同时玻璃网络结构的聚合度（N，非桥氧/桥氧的比例）减小，但是，随着B₂O₃的含量（B₂O₃的质量与剩余氧化物质量的比值）由0.117增加到0.143，再到0.176，桥氧键的比例先减小后增大。在本实验的范围内，废物玻璃固化体的密度变化不明显，无析晶现象。

Effects of SiO2 and B2O3 Content on Structure of Simulated High-Level Waste Glasses

Borosilicate glass has been widely used as a basal frit for the solidification of high-level waste due to its excellent chemical stability,good thermal stability,and high glass tolerance for radioactive waste properties.There is inherent dependence relationship between the structure of waste glass solidified bodies and its composition,which will have impact on the properties of waste glass.The contents of waste glass composition are considered as variables that will give rise to the change of certain structural characteristics of waste glass solidified bodies,which is an internal thread to explore the influence on the performance of high-level waste glass solidified bodies.The aim of this study is to obtain the influence rule of the content of waste glass composition on its structural feature parameters(such as the fraction of non-bridging oxygen)and to estimate the properties of waste glass solidified body,and then to provide a guidance for designing an optimal formula of waste glass for highly efficient disposal of high-level waste.In this study,a series of waste glass samples were prepared on the basis of the formula for certain simulated high-level waste glass solidified body,but the glass composition was changed as a function of SiO2 or B2O3 content.Furthermore,the Raman spectroscopy is applied for analysis of the silicate networks structure unit(Q n,where Q and n represents the tetrahedral unit and the number of bridging oxygen per tetrahedron,respectively)of the waste glasses.And the influence of the content of SiO 2 and B2O3 on the network structure of the waste glass solidified bodies was discussed.The results show that an increase of the fraction of bridging oxygen with increase of SiO2 content(mass ratio of SiO2 to that of all the other oxides)from 0.721 to 1.037 and in the meantime silicate network polymerization degree(N)as indicated by the ratio of non-bridging oxygen/bridging oxygen decrease.However,the fraction of bridging oxygen first decreases with B2O3 content(mass ratio of B2O3 to that of all the other oxides)reaching to 0.143 from 0.117 and then increases with further increase of B2O3 content to 0.176.The density determinations have shown close results and no crystallization are observed on the waste glass solidified bodies within our scope of the experiments.