γ辐照对高庙子钠基膨润土矿物成分和微观结构的影响

The influence of γ-ray irradiation on the mineral components and microstructures of the Gaomiaozi sodium-based bentonite

为了解γ辐照对高庙子天然钠基膨润土中矿物组分和微观结构的影响,拓展高放地质处置缓冲材料性能评价范围,以内蒙古高庙子天然钠基膨润土和北山地下水为研究对象,利用红外光谱仪、X射线衍射仪和穆斯堡尔谱仪分析了不同γ辐照剂量(500、1000、1500、2000、2500和3000kGy)照射后的高庙子天然钠基膨润土中基团、矿物组分以及Fe的赋存状态和含量变化,并对其中Si元素在北山地下水中的溶解性进行测试。结果表明,随着累积辐照剂量的增加,膨润土中Fe(Ⅱ)含量明显增大,Fe(Ⅲ)含量显著减小;可溶性偏硅酸根随累积辐照剂量的增加而增加;辐射后膨润土的相关基团数量有所变化,蒙脱石含量增加,石英和钠长石含量下降,但没有发生种类变化。总体而言,γ辐照引起了高庙子天然钠基膨润土某些参数的显著变化,具体变化有待深入研究。

In order to understand the impact of gamma irradiation on the mineral components and microstructures of the Gaomiaozi(GMZ)natural sodium-based bentonite and to expand the assessment scope of properties of buffer materials for the geological disposal of high-level radioactive wastes(HLW),the GMZ natural sodium-based bentonite in Inner Mongolia and groundwater from the Beishan area have been selected as research objects for studying the variation of functional groups,mineral components,and occurrences and contents of iron of the GMZ natural sodium-based bentonites which were gamma irradiated with accumulative irradiation dosages of 500 kGy,1000 kGy,1500 kGy,2000 kGy,2500 kGy,and 3000 kGy,respectively by using methods of the FTIR,XRD,and M?ssbauer spectrometry in this paper.In addition,the Si solubility of the bentonite into groundwater in the Beishan area has also been studied.The results indicate that Fe(Ⅱ)contents of bentonites are obviously increased but Fe(Ⅲ)contents of bentonites are decreased significantly with the increase of the accumulative irradiation dosages.The concentrations of SiO32-in groundwater are increased obviously with the increase of irradiation dosages.The gamma irradiation may cause a certain variation of numbers of functional groups in the irradiated bentonite.The percentages of montmorillonite are increased,but those of quartz and albite are decreased,with no variation in numbers of minerals and functional groups in the bentonite.In general,some properties of the GMZ natural sodium-based bentonite are obviously varied after theγ-ray irradiation on the bentonite.The detailed variation of those properties needs to be furtherly studied.