强碱性溶液扩散对高庙子膨润土的化学腐蚀

doi:10.13722/j.cnki.jrme.2019.0417

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摘要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/cm3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。

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	张虎元1
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	童艳梅2
	贾全全2

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

Abstract：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/cm3，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.

Key words： soil mechanics')" href="#">

soil mechanics bentonite montmorillonite alkaline solution dissolution XRD；SEM

引用本文:

张虎元1，2，童艳梅2，贾全全2. 强碱性溶液扩散对高庙子膨润土的化学腐蚀[J]. 岩石力学与工程学报, 2020, 39(1): 166-176.
ZHANG Huyuan1，2，TONG Yanmei2，JIA Quanquan2.

Corrosion of GMZ bentonite by diffusion of strong alkaline solution

. , 2020, 39(1): 166-176.

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http://www.rockmech.org/CN/10.13722/j.cnki.jrme.2019.0417 或 http://www.rockmech.org/CN/Y2020/V39/I1/166

[33]	PUSCH R，YONG R. Microstructure of smectite clays and engineering performance[M]. Abingdon：Taylor and Francis，2006：300-305.
[19]	SAVAGE D. Review of the potential effects of alkaline plume migration from a cementitious repository for radioactive waste[R]. London：UK Environment Agency，1997.
[1]	National Research Council of the United States. The disposal of radioactive waste on land[R]. Washington：National Academy Sciences，1956.
[21]	MITCHELL J K. Fundamentals of soil behavior[M]. New York：John Wiley and Sons Inc.，1993：154-158.
[16]	ADENOT F，BUIL M. Modelling of the corrosion of cement paste by deionized water[J]. Cement and Concrete Research，1992，22：489-496.
[29]	GAUCHER E C，BLANCA P，MATRAYB J M，et al. Modeling diffusion of an alkaline plume in a clay barrier[J]. Applied Geochemistry，2004，19：1 505-1 515.
[7]	VILLA R V，CUEVAS J，RAMIREZ S，et al. Zeolite formation during the alkaline reaction of bentonite[J]. European Journal of Mineralogy，2001，13：635-644.
[8]	BAUER A，VELDE B. Smectite transformation in high molar KOH solutions[J]. Clay Minerals，1999，34(2)：259-273.
[20]	PUSCH R. Geological storage of highly radioactive waste-current concepts and plans for radioactive waste disposal[M]. Berlin：Springer，2008：127-154.
[3]	TAYLOR，HARRY F W. A method for predicting alkaline concentrations in cement pore solutions[J]. Advances in Cement Research，1987，1(1)：5-16.
[6]	FERNÁNDEZ R，K MÄDER U，RODRÍGUEZ M，et al. Alteration of compacted bentonite by diffusion of highly alkaline solutions[J]. European Journal of Mineralogy，2009，21(4)：725-735.
[9]	陈宝，张会新，陈萍. 高碱溶液对高庙子膨润土侵蚀作用的研究[J]. 岩土工程学报，2013，35(1)：181-186.(CHEN Bao，ZHANG Huixin，CHEN Ping. Erosion effect of hyper-alkaline solution on Gaomiaozi bentonite[J]. Chinese Journal of Geotechnical Engineering，2013，35(1)：181-186.(in Chinese))
[11]	陈宝，张会新，陈萍. 高碱性溶液对高庙子膨润土溶蚀作用的研究[J]. 岩石力学与工程学报，2012，31(7)：1 478-1 483.(CHEN Bao，ZHANG Huixin，CHEN Ping. Laboratory test on unsaturated hydraulic conductivity of densely compacted Gaomiaozi bentonite under confined conditions[J]. Chinese Journal of Rock Mechanics and Engineering，2012，31(7)：1 478-1 483.(in Chinese))
[13]	FERNÁNDEZ R，CUEVAS J，MÄDER U K. Modeling experimental results of diffusion of alkaline solutions through a compacted bentonite barrier[J]. Cement and Concrete Research，2010，40(8)：1 255-1 264.
[23]	VILLAR M V，LLORET A. Influence of temperature on the hydro- mechanical behaviour of a compacted bentonite[J]. Applied Clay Science，2004，26(1/2/3/4)：337-350.
[26]	TAKASE H. Discussion on PA model development for bentonite barriers affected by chemical interaction with concrete：Do we have enough evidence to support bentonite stability?[C]// Proceedings of International Workshop on Bentonite-Cement Interaction in Repository Environments. Tokyo，Japan：[s. n.]，2004.
[31]	ODA C，WALKER C，CHINO D，et al. Na-montmorillonite dissolution rate determined by varying the Gibbs free energy of reaction in a dispersed system and its application to a coagulated system in 0.3M NaOH solution at 70 ℃[J]. Applied Clay Science，2014，93/94：62-71.
[4]	PUSCH R，ZWHAR H，GERBER R，et al. Interaction of cement and smectitic clay-theory and practice[J]. Applied Clay Science，2003，23：203-210.
[14]	FERNÁNDEZ R，CUEVAS J，SÁNCHEZ L，et al. Reactivity of the cement-bentonite interface with alkaline solutions using transport cells[J]. Applied Geochemistry，2006，21(6)：977-992.
[24]	SHIRAZI S M. The influence of temperature on swelling characteristics of compacted bentonite for waste disposal[J]. Environment of Asia，2010，3(1)：284-286.
[34]	NAKAYAMA S，SAKAMOTO Y，YAMAGUCHI T，et al，Iida. Dissolution of montmorillonite in compacted bentonite by highly alkaline aqueous solutions and diffusivity of hydroxideions[J]. Applied Clay Science，2004，27：53-65.
[2]	PUSCH R. Highly compacted sodium bentonite for isolating rock- deposited radioactive Waste Products[J]. Nuclear Technology，1979，45(2)：153-157.
[5]	SÁNCHEZ L，CUEVAS J，RAMÍREZ S，et al. Reaction kinetics of FEBEX bentonite in hyperalkaline conditions resembling the cement- bentonite interface[J]. Applied Clay Science，2006，33(2)：125-141.
[10]	陈宝，张会新，陈萍. 高碱溶液入渗对GMZ膨润土微观孔隙结构的影响[J]. 浙江大学学报：工学版，2013，47(4)：602-608. (CHEN Bao，ZHANG Huixin，CHEN Ping. Influence of hyper-alkaline solution infiltration on microscopic pore structure of compacted GMZ bentonite[J]. Journal of Zhejiang University：Engineering Science，2013，47(4)：602-608.(in Chinese))
[12]	陈宝，张会新，陈萍. 碱溶液对GMZ膨润土膨胀性和渗透性的影响[J]. 中南大学学报：自然科学版，2013，44(2)：737-742. (CHEN Bao，ZHANG Huixin，CHEN Ping. Performance alteration of compacted GMZ bentonite submitted to hyper-alkaline solution[J]. Journal of Central South University：Science and Technology，2013，44(2)：737-742.(in Chinese))
[15]	RAMÍREZ S，CUEVAS J，VIGIL R，et al. Hydrothermal alteration of“La Serrata”bentonite(Almeria，Spain) by alkaline solutions[J]. Applied Clay Science，2002，21(5/6)：257-269.
[17]	FAUCON P，ADENOT F，JACQUINOT J F，et al. Long-term behavior of cement pastes used for nuclear waste disposal：review of physico-chemical mechanisms of water degradation[J]. Cement and Concrete Research，1998，28：847-857.
[18]	张明，张虎元，贾灵艳，等. 缓冲回填材料的室内制样方法研究[J]. 建筑材料学报，2012，15(5)：638-643.(ZHANG Ming，ZHANG Huyuan，JIA Yanling，et al. Method for sample preparation of buffer/backfilling materials in laboratory[J]. Journal of Building Materials，2012，15(5)：638-643.(in Chinese))
[22]	张发忠，方振东，秦冰，等. 不同温度下膨润土膨胀变形行为研究[J]. 后勤工程学院学报，2017，33(2)：23-27.(ZHANG Fazhong，FANG Zhendong，QIN Bing，et al. Study on Bentonite¢s swelling strain behaviour at different temperatures[J]. Journal of Logistical Engineering University，2017，33(2)：23-27.(in Chinese))
[25]	DAUZERES A，LE BESCOP P，SARDINI P，et al. Physico-chemical investigation of clayey/cement-based materials interaction in the context of geological waste disposal：Experimental approach and results[J]. Cement and Concrete Research，2010，40(8)：1 327-1 340.
[27]	陈宝，毛耀建，张会新. 氢氧根离子在膨润土中的弥散规律及其溶蚀作用[J]. 地下空间与工程学报，2018，14(2)：436-443.(CHEN Bao，MAO Yaojian，ZHANG Huixin. Diffusion laws of OH－ in bentonite and its dissolution effect[J]. Chinese Journal of Underground Space and Engineering，2018，14(2)：436-443.(in Chinese))
[28]	YAMAGUCHI Y，SAKAMOTO Y，AKAI M，et al. Experimental and modeling study on long-term alteration of compacted bentonite with alkaline ground water[J]. Physics and Chemistry of the Earth，2007，32：298-310.
[30]	KARNLAND O，OLSSON S，NILSSON U，et al. Experimentally determined swelling pressures and geochemical interactions of compacted Wyoming bentonite with highly alkaline solutions[J]. Physics and Chemistry of the Earth，2007，32(1/7)：275-286.
[32]	WATSON C，WILSON J，SAVAGE D，et al. Coupled reactive transport modelling of the international long-term cement studies project experiment and implications for radioactive waste disposal[J]. Applied Geochemistry，2018，97：134-146.
[35]	MÄDER U，JENNI A，LEROUGE C，et al. 5-year chemico-physical evolution of concrete-claystone interfaces[J]. Swiss Journal of Geosciences，2017，110(1)：307-327.