【摘要】 为了探索Gd2Ti1.3Zr0.7O7烧绿石快速固化高放废物中锕系核素的方法,采用Sm模拟三价锕系核素,以氧化铜为氧化剂、钛粉为还原剂,氧化钆、氧化钐和二氧化锆为原料,利用自蔓延高温结合快速加压合成技术制备掺钐烧绿石陶瓷固化体,分别采用X射线衍射仪(XRD)、场发射扫描电镜(FESEM)、能谱仪(EDS)、电感耦合等离子体发射光谱-质谱(ICP-MS)和维氏硬度计研究样品的物相、微观组织形貌、元素分布、化学稳定性和力学性能。结果表明:自蔓延高温快速加压合成法在极短的时间(5min)内合成完全固溶的Gd2-xSmxTi1.3Zr0.7O7(0≤x≤0.2)烧绿石陶瓷固化体,烧绿石陶瓷固化体(x=0.2)的相对密度达92.8%,具有优异的化学稳定性;浸出时间为42d时,Gd和Sm的归一化浸出率分别为2.23×10-5 g·m-2·d-1、1.57×10-5g·m-2·d-1。更多还原

【Abstract】 In order to explore a rapid synthesis method for Gd2Ti1.3Zr0.7O7 pyrochlore immobilizing actinide elements from radioactive wastes.In this study,the synroc mineral of pyrochlore was employed as host phase for the immobilization of Sm²O₃,which was selected as surrogate of trivalent actinide nuclides.Gd2-xSmxTi1.3Zr0.7O7/Cu composites were rapidly synthesized by self-propagating high-temperature synthesis plus quick pressing（SHS/QP）using CuO as the oxidant and Ti as the reductant.The products were characterized by means of XRD,FESEM,EDS,ICP-MS and so on.The results show that among all the compositions,Gd2-xSmxTi1.3Zr0.7O7（0≤x≤0.2）solid solution with a cubic pyrochlore structure is synthesized within only 5min.The pyrochlore-base waste form（x=0.2）exhibits the relative density of 92.8%.Furthermore,the ceramic forms exhibit excellent aqueous durability.The 42 days normalized leaching rates of Gd and Sm were calculated to be 2.23×10-5 g·m-2·d-1and 1.57×10-5 g·m-2·d-1.更多还原