人造岩石固化体SrCeTi2O7的合成与性能研究

Synthesis and Property of SrCeTi2O7 Synroc for Immobilization of High Level Radioactive Waste

  • 摘要: 采用88Sr模拟放射性核素90Sr,Ce4+模拟四价锕系放射性核素。以分析纯SrCO3、CeO2和TiO2为主要原料,通过高温固相反应制备SrCeTi2O7人造岩石固化体。对固化体的烧成工艺、物理性能、晶体结构及微观形貌进行研究,并对固化体的热稳定性及抗浸出性能进行探讨。结果表明,选择配方n(SrCO3)∶n(CeO2)∶n(TiO2)=1∶1∶2,在1 450 ℃下保温5 h可合成结构致密、晶型发育完整的SrCeTi2O7人造岩石固化体;Dicvol程序指标化结果表明,该固化体化合物属四方晶系,晶胞参数为a=0.387 33(4) nm,c=0.388 07(5) nm;SrCeTi2O7人造岩石固化体具有良好的热稳定性,经高达800 ℃热处理后样品仍保持原有物相不变;PCT-B粉末浸泡法测试结果表明,SrCeTi2O7人造岩石固化体具有较好的抗浸出性能,浸泡周期28 d时Sr、Ce和Ti的浸出率分别为3.51×10-4、8.23×10-8和2.02×10-7 g/(m2·d)。

     

    Abstract: Simulating radionuclide 90Sr with 88Sr and tetravalent actinides radionuclides with Ce4+, using analytical SrCO3, CeO2 and TiO2 as raw materials, the SrCeTi2O7 synroc was synthesized through a high temperature solid-state method. The synthesis technology, physical properties, crystal structure and microstructure of SrCeTi2O7 synroc were researched. The thermal stability and leaching performance were also investigated. The results show that when selecting formulation as n(SrCO3)∶n(CeO2)∶n(TiO2)=1∶1∶2, sintering at 1 450 ℃ with holding time 5 h can synthesize SrCeTi2O7 synroc with dense structure and well crystallized. Indexing results show that SrCeTi2O7 synroc crystallizes as a tetragonal structure with the lattice parameters are a=0.387 33(4) nm, c=0.388 07(5) nm. The SrCeTi2O7 synroc has excellent thermal stability, and it maintains the SrCeTi2O7 phase after 800 ℃ heat treatment. Product consistency test shows SrCeTi2O7 synroc has good leaching performance, and the leaching rate of Sr, Ce and Ti are 3.51×10-4, 8.23×10-8 and 2.02×10-7 g/(m2·d) in 28 days, respectively.

     

  • 分享
  • 用微信扫码二维码

    分享至好友和朋友圈