强碱性溶液扩散对高庙子膨润土的化学腐蚀
Corrosion of GMZ bentonite by diffusion of strong alkaline solution
查看参考文献35篇
|
文摘
|
高放废物地下处置库中,地下水腐蚀衬砌混凝土析出的强碱性溶液,会扩散进入膨润土缓冲屏障内部,引起屏障性能的退化。设计专门的扩散试验单元,模拟KOH强碱性溶液在压实高庙子膨润土试样内部的扩散过程,研究辐射升温条件下膨润土中蒙脱石矿物含量及微结构变化,为我国高庙子膨润土缓冲屏障长期性能评价提供依据。设计24组正交试验,对初始干密度为1.80 g/cm~3的压实膨润土开展KOH扩散试验,工况组合条件为:pH值为12.6,13.0和13.5,环境温度T为30 ℃和60 ℃,反应时间t为7,14,21和28 d。扩散试验终结之后对试样开展X射线衍射(XRD)和扫描电镜(SEM)试验。试验结果证实,高庙子膨润土中蒙脱石矿物溶解损失,与溶液pH值和试验温度的升高成正相关关系,显著溶解发生在接触带2 mm以内,最严重的情形下蒙脱石含量从初始的44.4%减少到25.9%。蒙脱石矿物的溶失可能与蒙脱石水化产生的羽翼状胶体的溶解有关。碱溶液对膨润土结构的损伤程度随扩散深度减缓,表观孔隙率逐渐降低。接触界面上肉眼观察到腐蚀裂隙;接触带0~4 mm范围内,膨润土团聚体结构遭受一定的破坏;大于4 mm的范围,微结构形态基本保持不变。关于高庙子膨润土缓冲屏障长期性能的化学演化,今后应关注溶液化学性质、水力条件及固液反应时间等因素的影响。 |
|
其他语种文摘
|
In the underground repository of high-level wastes,strong alkaline cementitious material dissolved by groundwater from the lining concrete will penetrate into bentonite buffer,resulting in a certain degradation of the performance of the buffer barrier.A diffusion cell was particularly designed to simulate the diffusion process of KOH solution into compacted GMZ bentonite specimens,so to investigate the possible changes in clay minerals and microstructure under elevated temperature for the purpose of long-term evaluation of GMZ bentonite buffer in China.Totally,24 sets of KOH diffusion tests were conducted on bentonite specimens with an initial dry density of 1.80 g/cm~3,covering combinations of pH = 12.6,13.0 or 13.5,temperature of 30 ℃ or 60 ℃ and reaction time of t = 7,14,21 or 28 d.As soon as diffusion tests terminated,bentonite specimens were disassembled to carry out X-ray diffraction(XRD) and scanning electron microscopy(SEM) analysis.Research results verify that the dissolution loss of montmorillonite in bentonite has a positive correlation with pH and temperature and that the dissolution mainly concentrate within 0-2 mm from the contact surface with a max drop from original 44.4% to 25.9%.The alkaline dissolution of wing-like gels generated originally during bentonite hydration is responsible for the montmorillonite dissolution.Bentonite microstructure damage resulted from alkaline solution moderates with increasing the diffuse depth from the contact surface,accompanied by a decrease of the apparent porosity.Macro fissures on the contact surface are visible by naked eyes,aggregate destroy occurs within 0–4 mm from the contact surface but the microstructure almost keeps changeless while deeper than 4mm.With respect to the long term chemical evolution of bentonite barrier,further attention should be paid to solution chemistry,hydraulic condition and time scale of mineral-solution reactions. |
|
来源
|
岩石力学与工程学报
,2020,39(1):166-176 【核心库】
|
|
DOI
|
10.13722/j.cnki.jrme.2019.0417
|
|
关键词
|
土力学
;
膨润土
;
蒙脱石
;
碱溶液
;
溶解
;
X射线衍射
;
扫描电镜
|
|
地址
|
1.
兰州大学, 西部灾害与环境力学教育部重点实验室, 甘肃, 兰州, 730000
2.
兰州大学土木工程与力学学院, 甘肃, 兰州, 730000
|
|
语种
|
中文 |
|
文献类型
|
研究性论文 |
|
ISSN
|
1000-6915 |
|
学科
|
建筑科学 |
|
基金
|
国家自然科学基金
|
|
文献收藏号
|
CSCD:6678904
|
参考文献 共
35
共2页
|
|
1.
National Research Council of the United States.
The disposal of radioactive waste on land,1956
|
CSCD被引
1
次
|
|
|
|
|
2.
Pusch R. Highly compacted sodium bentonite for isolating rockdeposited radioactive Waste Products.
Nuclear Technology,1979,45(2):153-157
|
CSCD被引
28
次
|
|
|
|
|
3.
Taylor. A method for predicting alkaline concentrations in cement pore solutions.
Advances in Cement Research,1987,1(1):5-16
|
CSCD被引
1
次
|
|
|
|
|
4.
Pusch R. Interaction of cement and smectitic clay-theory and practice.
Applied Clay Science,2003,23:203-210
|
CSCD被引
3
次
|
|
|
|
|
5.
Sanchez L. Reaction kinetics of FEBEX bentonite in hyperalkaline conditions resembling the cement–bentonite interface.
Applied Clay Science,2006,33(2):125-141
|
CSCD被引
7
次
|
|
|
|
|
6.
Fernandez R. Alteration of compacted bentonite by diffusion of highly alkaline solutions.
European Journal of Mineralogy,2009,21(4):725-735
|
CSCD被引
6
次
|
|
|
|
|
7.
Villa R V. Zeolite formation during the alkaline reaction of bentonite.
European Journal of Mineralogy,2001,13:635-644
|
CSCD被引
2
次
|
|
|
|
|
8.
Bauer A. Smectite transformation in high molar KOH solutions.
Clay Minerals,1999,34(2):259-273
|
CSCD被引
8
次
|
|
|
|
|
9.
陈宝. 高碱溶液对高庙子膨润土侵蚀作用的研究.
岩土工程学报,2013,35(1):181-186
|
CSCD被引
12
次
|
|
|
|
|
10.
陈宝. 高碱溶液入渗对GMZ膨润土微观孔隙结构的影响.
浙江大学学报:工学版,2013,47(4):602-608
|
CSCD被引
6
次
|
|
|
|
|
11.
陈宝. 高碱性溶液对高庙子膨润土溶蚀作用的研究.
岩石力学与工程学报,2012,31(7):1478-1483
|
CSCD被引
17
次
|
|
|
|
|
12.
陈宝. 碱溶液对GMZ膨润土膨胀性和渗透性的影响.
中南大学学报:自然科学版,2013,44(2):737-742
|
CSCD被引
6
次
|
|
|
|
|
13.
Fernandez R. Modeling experimental results of diffusion of alkaline solutions through a compacted bentonite barrier.
Cement and Concrete Research,2010,40(8):1255-1264
|
CSCD被引
6
次
|
|
|
|
|
14.
Fernandez R. Reactivity of the cement-bentonite interface with alkaline solutions using transport cells.
Applied Geochemistry,2006,21(6):977-992
|
CSCD被引
11
次
|
|
|
|
|
15.
Ramirez S. Hydrothermal alteration of“La Serrata”bentonite(Almeria,Spain) by alkaline solutions.
Applied Clay Science,2002,21(5/6):257-269
|
CSCD被引
6
次
|
|
|
|
|
16.
Adenot F. Modelling of the corrosion of cement paste by deionized water.
Cement and Concrete Research,1992,22:489-496
|
CSCD被引
4
次
|
|
|
|
|
17.
Faucon P. Long-term behavior of cement pastes used for nuclear waste disposal:review of physico-chemical mechanisms of water degradation.
Cement and Concrete Research,1998,28:847-857
|
CSCD被引
6
次
|
|
|
|
|
18.
张明. 缓冲回填材料的室内制样方法研究.
建筑材料学报,2012,15(5):638-643
|
CSCD被引
10
次
|
|
|
|
|
19.
Savage D.
Review of the potential effects of alkaline plume migration from a cementitious repository for radioactive waste,1997
|
CSCD被引
2
次
|
|
|
|
|
20.
Pusch R.
Geological storage of highly radioactive waste-current concepts and plans for radioactive waste disposal,2008:127-154
|
CSCD被引
1
次
|
|
|
|
|
了解气象卫星更多信息，请访问