NZP型磷酸盐陶瓷固化模拟放射性核素Sr^(2+)/Sm^(3+)的研究  

Study on Immobilization of Simulated Radionuclide Sr^(2+)/Sm^(3+) by NZP-type Phosphate Ceramics

作　　者：张雪 王进[1] 罗萍 刘蝶 詹磊 魏玉锋 王军霞[1] ZHANG Xue;WANG Jin;LUO Ping;LIU Die;ZHAN Lei;WEI Yufeng;WANG Junxia(School of Materials Science and Engineering,Southwest University of Science and Technology,Mianyang 621010,Sichuan,China)

机构地区：[1]西南科技大学材料科学与工程学院,四川绵阳621010

出　　处：《材料导报》2022年第1期60-64,共5页Materials Reports

基　　金：国家自然科学基金青年基金(11705153)。

摘　　要：本工作以Sr^(2+)和Sm^(3+)分别模拟二价裂变核素和三价次锕系核素,利用NaZr_(2)(PO_(4))_(3)(NZP)结构丰富的离子取代性同时固化多种模拟放射性核素,采用微波烧结工艺在1100℃保温2 h制备了固溶Sr、Sm的NZP型磷酸盐陶瓷固化体(Na,Sr)(Zr,Sm)_(2)(PO_(4))_(3),系统地研究了Sr/Sm掺入量对固化体的物相组成、微观形貌、表观密度以及维氏硬度的影响规律。研究结果表明:Sr能够完全固溶进入NZP结构的Na晶格位形成Sr_(0.5)-Zr_(2)(PO_(4))_(3)(SrZP),而Sm难以进入NZP的Zr晶格位,掺入的Sm主要以SmPO_(4)独居石的形式存在。固溶Sr/Sm的陶瓷固化体结构致密,晶粒大小均匀,且SmPO_(4)独居石的存在不会降低固化体的致密性和力学性能;随着Sm掺入量的增加,样品的表观密度和维氏硬度逐渐增大,最大值分别为3.61 g·cm^(-3)和679 MPa。同时,PCT浸出结果表明所制备的样品具有良好的化学稳定性,各元素的归一化浸出率均处于10^(-3)~10^(-7) g·m^(-2)·d^(-1)。In this work,Sr^(2+) and Sm^(3+) were chosen as surrogates for the fission nuclide and minor actinides,respectively.NaZr_(2)(PO_(4))_(3)(hereinafter referred to as NZP)was employed to simultaneously incorporate the multiple simulated radionuclides due to its abundant ionic substitution,and a series of Sr^(2+) and Sm^(3+) incorporated NZP-type(Na,Sr)(Zr,Sm)_(2)(PO_(4))_(3) ceramics waste forms were prepared by microwave sintering at 1100℃holding for 2 h.The effects of Sr/Sm content on the phase composition,micromorphology,apparent density,and Vickers hardness of the samples were systematically investigated.It was shown that Sr was incorporated in the Na lattice of NZP structure to form Sr_(0.5)Zr_(2)(PO_(4))_(3)(SrZP),while Sm was difficult to enter Zr lattice site of NZP,but mainly existed in the form of SmPO_(4) monazite phase.The Sr/Sm-incorporated ceramics waste forms exhibited an excellent dense structure with uniform grain size,and the existence of SmPO_(4) monazite would not lower its densification and physical properties.The apparent density and Vickers hardness of the samples increased gradually with the increase of Sm content,which were up to 3.61 g·cm^(-3) and 679 MPa,respectively.Moreover,it was indicated that the as-prepared samples exhibited great chemical stability according to PCT test results,and the normalized leaching rate of each element was in the order of 10^(-3)-10^(-7) g·m^(-2)·d^(-1).

关 键 词：磷酸锆钠(NZP) 固化 放射性核素 独居石 微波烧结 

分 类 号：TQ174[化学工程—陶瓷工业]