硼硅酸盐玻璃固化体蚀变层结构及浸出行为研究  

Alteration Layer Structure and Leaching Behavior of Borosilicate Glass Waste Forms

作　　者：张海洋 吴浪[1] 王宾 姚颖 康泽 ZHANG Haiyang;WU Lang;WANG Bin;YAO Ying;KANG Ze(School of Materials Science and Engineering,Southwest University ofScience and Technology,Mianyang 621010,China)

机构地区：[1]西南科技大学材料科学与工程学院,绵阳621010

出　　处：《玻璃》2021年第5期7-14,共8页Glass

基　　金：国家自然科学基金(NO.11775182)。

摘　　要：采用挂片静态浸泡法评价了硼硅酸盐玻璃固化体经模拟地下水侵蚀长达364 d的浸出行为,用X射线衍射仪(XRD)和扫描电子显微镜-X射线能谱仪(BSE-EDS)等手段分析了蚀变层物相、形貌及成分随时间的变化情况。结果表明,浸泡56 d后玻璃固化体表面出现了蜂窝状的页硅酸盐,其结构疏松且孔隙较大,使得Si、B的浸出速率略有升高;91 d后由蜂窝状转变为短棒状形貌并出现了棱柱状CaCO_(3)和片状BaSO_(4)晶体,随着时间进一步延长其结构变得更加致密,Si、B的浸出速率因此逐渐下降且Si的浸出比B低一个数量级;蚀变层主要由富Mg硅酸盐二次相和凝胶层构成,其厚度随着浸泡时间的延长而增加,二次相厚度在182 d后基本保持不变;Cs在7 d内快速浸出后逐渐下降,U的浸出速率总体呈下降趋势。The leaching behavior of borosilicate glass waste forms by simulated groundwater erosion for 364 d was evaluated by monolithic static leaching method.The changes of phase,morphology and composition of the alteration layer with time were analyzed by X-ray diffractometry(XRD)and scanning electron microscope-X-ray energy dispersive spectroscopy(BSE-EDS).The results show that honeycomb-like phyllosilicate appears in the glass surface after leaching for 56 d.The alteration layer has a loose structure and large pores,leading to a slight increase in the leaching rate of Si and B.After 91 d,the honeycomb morphologies changes into short rods,and prismatic CaCO_(3) and flake-like BaSO_(4) crystals form.With further increasing the time,the structure of alteration layer becomes dense.The leaching rate of Si and B decreases gradually and the leaching rate of Si is one order of magnitude lower than that of B.The alteration layer is mainly composed of Mg-rich silicate secondary phase and gel.The thickness of the gel layer increases with the extension of leaching time,and the thickness of the secondary phase layer basically remains almost unchanged after 182 d.After rapid leaching of Cs within 7 d,the leaching rate of Cs decreases gradually,and the leaching rate of U shows a general decreasing trend.

关 键 词：硼硅酸盐玻璃 静态浸出 模拟地下水 蚀变层 

分 类 号：TL941[核科学技术—辐射防护及环境保护]