硝酸钡预处理高放废液玻璃固化体结构和抗浸出性能研究

Structure and Leaching Resistance of Ba(NO_(3))^(2-) Pretreated High-Level Liquid Glass Waste Form

为提高硼硅酸盐玻璃对硫的包容能力,采用Ba(NO_(3))_(2)将模拟高硫高钠废液中的SO_(4)^(2-)转变为BaSO_(4),再利用熔融法制备硼硅酸盐玻璃固化体,研究了模拟高放废液掺量对玻璃固化体结构和抗浸出性能的影响。结果表明:采用Ba(NO_(3))_(2)对模拟高硫高钠废液进行预处理后,废物包容量达到23%(质量分数)仍未发生分相;掺入模拟高放废液的玻璃固化体中的Na、B、Si元素归一化质量损失比纯硼硅酸盐玻璃低一个数量级,随着模拟高放废液掺量增加玻璃固化体抗浸出性能无明显变化。^(11)B和^(29)Si核磁共振谱分析表明,模拟高放废液的掺入使部分BO_(3)结构转变为BO_(4)结构,玻璃网络结构有所增强。

In order to increase solubility of sulfur in borosilicate glass,SO_(4)^(2-)ions in simulated high-level liquid waste(HLLW)with relatively high content of sulfur and sodium were pretreated by adding Ba(NO_(3))_(2)solution,and then borosilicate glass waste form was prepared by melt-quenching method.The effects of pretreated HLLW on the structure and leaching resistance were mainly investigated.The results show that the waste loading can be increased to 23%(mass fraction)without phase separation after the Ba(NO_(3))_(2)pretreatment.The normalized elemental mass loss of Na,B and Si of the HLLW-loaded samples are one order of magnitude lower than that of the pure borosilicate glass.Furthermore,the leaching resistance of the glass waste form has no significant change with increasing HLLW content.11 B and 29 Si MAS NMR analyses indicate that part of BO_(3)transforms into BO_(4)structural units and a polymerization of the glass network occurs after HLLW addition.