摘要
玻璃固化技术是国内外目前主要的高放废液固化处理手段。针对模拟高燃耗动力堆高放废液,研究了废物氧化物包容量为24%(质量分数,下同)和30%时玻璃固化体在不同热处理温度下的析晶行为以及析晶对玻璃固化体抗浸出性能的影响。根据X射线衍射、拉曼光谱和扫描电子显微镜分析结果,当热处理温度为800℃时,玻璃固化体析出晶体相为树枝状的钼酸钙CaMoO_(4)和丝状的锆铈氧化物Zr_(x)Ce_(1-x)O_(2);当热处理温度为950℃时,除钼酸钙和锆铈氧化物之外,玻璃固化体中还有大量的空心六方柱形的硅氧磷灰石相Ca_(2)Ln_(8)(SiO_(4))_(6)O_(2)析出。根据抗浸出性能检测结果,玻璃固化体经热处理析晶后其归一化质量损失降低了约1/3,B、Na、Mo、Ca等的归一化质量损失也有明显下降。且950℃热处理比800℃热处理后的玻璃固化体归一化质量损失更小。结果表明热处理析晶可提升玻璃固化体抗浸出性能。
Vitrification is currently the primary choice worldwide for high-level nuclear waste immobilization. This study investigated the crystallization behaviors of glasses containing 24%(mass fraction) and 30% simulated high-level nuclear waste, respectively, under different temperatures. According to X-ray diffraction, Raman spectroscopy and scanning electronic microscopy results, dendritic powellite(CaMoO_(4)) phase and string-like Zr-cerianite(Zr_(x)Ce_(1-x)O_(2)) are the main crystalline phases when the glasses are heat treated at 800 ℃, while a great amount of hollow hexagonal oxyapatite(Ca_(2)Ln_(8)(SiO_(4))_(6)O_(2)) phases are observed in addition when the glasses are heated at 950 ℃. The chemical durability test shows that the heat treatment decreases the total normalized leaching mass loss of glass by about 1/3, with main contributions from B, Na, Mo and Ca. The normalized leaching mass loss of the glasses after heat treatment at 950 ℃ is smaller than that after heat treatment at 800 ℃. It indicates that the heat treatment of glass for crystallization improves glass durability.
作者
常煚
朱冬冬
王佳腾
贺诚
刘潇
张华
谭盛恒
CHANG Jiong;ZHU Dong-dong;WANG Jia-teng;HE Cheng;LIU Xiao;ZHANG Hua;TAN Sheng-heng(China Institute of Atomic Energy,P.O.Box 275(93),Beijing 102413,China)
出处
《核化学与放射化学》
CAS
CSCD
北大核心
2023年第1期22-31,共10页
Journal of Nuclear and Radiochemistry
基金
核废料玻璃固化中关键元素行为研究(BJ19001703)。
关键词
玻璃固化
钼酸盐
稀土氧化物
析晶
抗浸出性能
vitrification
molybdate
rare earth oxides
crystallization
glass chemical durability
