高放废液煅烧物与基础玻璃高温反应物相与结构转变研究

Phase and Structure Transitions of High-Level Liquid Waste Calcine and Glass at Elevated Temperature

高放废液玻璃固化是我国亟待突破的关键环节之一,而高放废液玻璃固化过程中高放废液与基础玻璃反应发生的物相转变与结构变化一直是关注的重点。本文以模拟高放废液煅烧物和基础玻璃的混合物为研究对象,利用DSC、原位XRD、NMR、Raman等表征方法开展玻璃固化过程中高温反应物相与结构变化研究。研究结果表明:模拟高放废液煅烧物在~700℃开始溶解于基础玻璃中,并在800~900℃生成系列硅(铝)酸盐中间物相;煅烧物与基础玻璃高温反应过程中,高放废液中的大量玻璃网络改变体溶入基础玻璃中,导致玻璃网络聚合度下降。

The vitrification of high-level liquid waste(HLLW)is one of the challenges in the reprocessing of spent nuclear fuel in China.The feed-to-glass conversion comprising quite complex chemical reactions and structure transitions has been of great concern.In this paper,the phase and structure transitions of the heat-treated feed(mixture of simulated HLLW calcine and glass frit)during vitrification were analyzed with DSC,in-situ XRD,NMR and Raman.The results show that the simulated HLLW calcine begins to dissolve in the glass frit at~700℃,and the intermediate phases of aluminosilicates appeare at 800~900℃.During the reactions of HLLW calcine and glass frit at elevated temperatures,most of network modifiers from HLLW enter into the glass network of glass frit,resulting in a decrease of the network polymerization.