Nd_(2)O_(3)取代CaO对硼硅酸盐玻璃物相、结构和化学稳定性的影响

Effects of the Substitution of Nd_(2)O_(3) for CaO on the Phase Composition, Structure and Chemical Stability of Borosilicate Glasses

以典型Na_(2)O-CaO-ZrO_(2)-B_(2)O_(3)-SiO_(2)为基础玻璃组分,通过Nd_(2)O_(3)替换CaO,采用传统的高温熔融冷却法制备了固化体。通过X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)和扫描电子显微镜(SEM)对固化体进行了物相和结构的表征,并通过产品一致性检测法(PCT)和溶解速率法(MCC-1)对化学稳定性进行了分析和评估。结果表明:随着Nd_(2)O_(3)取代量的增加,ZrO_(2)的析晶逐渐减弱,当Nd_(2)O_(3)的含量为5%时,6%的ZrO_(2)能完全溶于玻璃相中。通过Nd_(2)O_(3)替换CaO促进ZrO_(2)在该硼硅酸盐玻璃结构中的溶解,可提高固化体的化学稳定性。浸泡28天后,固化体的LRSi、LRCa、LRZr和LRNd在10^(-4)g/(m^(2)·d)数量级及以下,失重速率在10^(-9)g/(cm^(2)·min)数量级,其主要浸出的元素是Na和Ca。因此,本研究为富含Zr和Nd的高放废液固化提供了理论支撑和实验指导。

With typical Na_(2)O-CaO-ZrO_(2)-B_(2)O_(3)-SiO_(2)as the basic glass component,the immobilization products were prepared by the traditional melting cooling method by replacing CaO with Nd_(2)O_(3).The phase and structure of immobilization products were characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR)and scanning electron microscopy(SEM),and the chemical stability was analyzed and evaluated by product consistency test(PCT) and dissolution rate method(MCC-1).The results show that the crystallization of ZrO_(2)decreases with increasing substitution of Nd_(2)O_(3).When the content of Nd_(2)O_(3)is 5%,6% ZrO_(2)was completely dissolved in glass phase.The chemical stability of immobilization products can be improved by replacing CaO with Nd_(2)O_(3)to promote the dissolution of ZrO_(2)in this borosilicate glass.After 28 days of immersion,the LRSi,LRCa,LRZrand LRNdof immobilization products remained below the order of 10^(-4)g/(m^(2)·d),the weight loss rate remained at the order of 10^(-9)g/(cm^(2)·min),and the main leaching elements are Na and Ca.Therefore,this study provides theoretical support and experimental guidance for the immobilization of high-level waste rich in Zr and Nd.