铈模拟放射性废物固化体的物理化学性质  

Physicochemical Properties of Simulated Radioactive Waste Formed with Cerium

作　　者：毛仙鹤[1] 袁晓宁[1] 秦志桂[1] 陈旻[1] 赵康[1] 杨萍[1] 

机构地区：[1]西北核技术研究所,西安710024

出　　处：《硅酸盐学报》2012年第1期131-136,共6页Journal of The Chinese Ceramic Society

摘　　要：以稀土元素Ce作为示踪核素,采用铝热剂自蔓延高温合成技术固化了粒度≤200μm的模拟核废物土壤,通过密度测定和扫描电子显微镜、X射线荧光光谱、X射线衍射、电感耦合等离子发射光谱分析,研究了不同Ce含量的固化体的组成结构和核素浸出率。结果表明:在CeO2质量分数大于1%的情况下,示踪核素Ce主要是以CeAl11O18和Ce2SiO5的矿物晶体的形态存在于固化产物中。产物为无定形态玻璃和陶瓷体的混合物,体积密度超过3.0 g/cm3。固化体中示踪核素Ce的28 d平均浸出速率为10-5～10-6 g/(m2.d),比一般硼硅酸盐玻璃固化体中稀土元素的浸出速率低1～2个数量级。固化体中Ca、Si和Al的28d浸出速率约为10-3g/(m2.d),Fe的28d浸出率约为10-4g/(m2.d)。A simulated radioactive sandy soil waste with the particle size of ≤200 μm was immobilized using anthanon Ce as a tracer element by a thermit self-propagating high temperature synthesis（SHS） process.The composition,the structure and the normalized release rate of the products with different Ce contents were characterized by scanning electron microscopy,measurement of density,X-ray diffraction,X-ray fluorescence analysis,inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectroscopy（ICP-AES）.The results show that the tracer element Ce mainly forms the crystalline phases CeAl11O18 and Ce2SiO5 when the amount of CeO2 is 1%（in mass）.The self-propagating high-temperature synthesis immobilization resulted in vit-reous products with the amorphous phase particles and crystallines dispersed in the matrix.The volume density was over 3.0 g/cm3.The normalized release rate of Ce during 28 d was 10-5-10-6 g/（m2？d）,which was lower than that of borosilicate glass.The normalized release rate of Ca,Si and Al during 28 d was 10-3 g/（m2？d） and the release rate of Fe was 10-4 g/（m2？d）.

关 键 词：铈 自蔓延高温合成 固化 核废物 土壤 

分 类 号：TQ174[化学工程—陶瓷工业]