热处理工艺对钙钛锆石基玻璃陶瓷固化体结构和化学稳定性的影响

Effect of Heat Treatment Process on the Structure and Chemical Stability of Zirconolite-based Glass-ceramic Immobilizations

通过“高温熔融-急速冷却”首先制备36.5SiO_(2)-9.9B_(2)O_(3)-7.3Na_(2)O-3.0Al_(2)O_(3)-10.3CaO-23.6TiO_(2)-9.4ZrO_(2)基础玻璃,再掺入质量分数30%的全组分,以“高温熔融-热处理工艺”制备玻璃陶瓷固化体,通过XRD、DSC、SEM、FTIR、Raman、ICP-MS等多种表征方法来探究固化体在析晶、结构和化学稳定性方面的差异。结果表明:随炉冷却和2℃/min冷却制备的固化体主晶相均为钙钛锆石,固化体内部钙钛锆石为长条状,表面为片状;随冷却速率提高,固化体密度和硬度提高,经过28 d天浸出实验,固化体标准化质量损失以及Ca、Zr、La、Ce、Nd元素的归一化质量损失均远远小于中国核工业标准,说明该钙钛锆石基玻璃陶瓷固化体化学稳定性良好。

36.5SiO_(2)-9.9B_(2)O_(3)-7.3Na_(2)O-3.0Al_(2)O_(3)-10.3CaO-23.6TiO_(2)-9.4ZrO_(2) base glass was first prepared by "high-temperature melting-rapid cooling",and then 30% of the whole components were mixed to prepare the glass-ceramic immobilizations by "high-temperature melting-heat treatment process",and the immobilizations were explored by XRD,DSC,SEM,FTIR,Raman,ICP-MS and other characterization methods,structural and chemical stability.The results show that the main crystal phase of the solidified body prepared by furnace cooling and 2 ℃/min cooling is zirconolite,and the zirconolite inside the immobilization is long strip and the surface is flaked.With the increase of cooling rate,the density and hardness of the immobilizations increased,and after 28 days of leaching experiment,the normalized mass loss of the immobilizations and the normalized mass loss of Ca,Zr,La,Ce,and Nd elements were much smaller than those of the Chinese nuclear industry standard,indicating that the zirconolite-based glass-ceramic immobilizations had good chemical stability.