LiNO3对石英玻璃与NaOH溶液反应的影响

摘要

The control of alkali-silica reaction(ASR)for the process of quartz glass soaked in NaOH solution by the use of LiNO3was investigated.Inductively coupled plasma was carried out to analyze concentrations of species(Si,Na and Li)in filtrates at different ages.The content of silica products was quantitatively determined over time via acidification method.The phase composition and microstructure of the reaction products were characterized by X-ray diffraction(XRD)and scanning electron microscope (SEM).Results showed that Li+ was involved in ASR prior to Na+ in NaOH solution with the presence of LiNO3.The formation of Li-based products prevented quartz glass from further attack by OH-,decreasing the dissolution rate of quartz glass and the solubility of silica,and then delayed the reaction rate of ASR. The Li-based solid products varied with curing temperatures.The main products at 38 ℃ were Li-contained gels,and Li2SiO3 at the surface of quartz glass at 60 ℃.Li2SiO3 could be easily crystallized through increasing the curing temperature.%将LiNO3掺入浸泡有石英玻璃的NaOH溶液中,研究其对碱硅酸反应(ASR)的影响.采用等离子发射光谱仪测试溶液中Na、Si和Li元素浓度,采用酸化处理法分析固相中SiO2含量,采用X线衍射仪(XRD)和扫描电子显微镜(SEM)分析固相产物的组成和微观形貌.结果表明:在含LiNO3的NaOH溶液中,Li+优先于Na+与溶液中SiO4-4反应,形成的含锂产物阻止了OH-对石英玻璃的进一步破坏,降低了NaOH溶液中石英玻璃的溶蚀率和溶液中SiO2的溶解度,减缓了ASR的反应速率;不同养护温度下反应形成的含锂产物不同,38 ℃下主要反应产物为含锂凝胶,60 ℃下反应形成不溶于水的Li2SiO3晶体,提高养护温度有利于Li2SiO3晶体的形成.