MECHANISMS CONTROLLING HYDRAULIC CONDUCTIVITY OF BENTONITE CLAY LINERS WITH BAUXITE LIQUOR
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摘要: 赤泥渗滤液的高离子强度可以抑制蒙脱石的膨胀,从而导致钠基膨润土黏土衬垫(GCL)的渗透性过强,并无法用作赤泥处理设施中的防渗衬层。通过2种钠基膨润土黏土衬垫与2种赤泥渗滤液的渗透过程,研究强碱性赤泥渗滤液与钠基膨润土黏土衬垫的渗透机理。结果表明:天然钠基膨润土(Na-GCL)和人工钠化钠基膨润土(Ar-GCL)的渗透系数与赤泥渗滤液的离子强度密切相关,随着离子强度的增加,渗透系数呈递进式系统性增大,对高离子强度的山东赤泥渗滤液的渗透系数最大,分别为7.8×10-7,3.2×10-7 m/s。且两者的渗透系数与膨胀指数呈正相关,SEM扫描的微观结构分析发现,膨润土的膨胀机理控制着其渗透作用。高离子强度会使膨润土中的蒙脱石矿物层间发生渗透性膨胀,并吸收大量的水分,减小孔隙度的同时改变流体的流动路径,从而导致渗透系数提高。该结果可为赤泥堆场底部防渗设计提供更为可靠的理论参考,有效降低我国赤泥堆场渗滤液污染风险。Abstract: The high ionic strength of bauxite liquor could suppress swelling of montmorillonite, which results in sodium bentonite clay liner (GCL) that was too permeable to be used as an impermeable liner in red mud treatment facilities. The mechanism controlling of strongly alkaline bauxite liquor and sodium bentonite clay liner was investigated through the infiltration process of sodium bentonite clay liner and two types of bauxite liquor. The results showed that hydraulic conductivity of natural sodium bentonite (Na-GCL) and artificial sodium bentonite (Ar-GCL) was closely related to ionic strength of bauxite liquor. As ionic strength increased, hydraulic conductivity systematically increased. Hydraulic conductivity of Shandong bauxite liquor with high ionic strength was the largest, 7.8×10-7 and 3.2×10-7 m/s, respectively. Hydraulic conductivity was positively related to swelling index. Through the analysis of the microstructure diagram of SEM scanning, swelling mechanism of bentonite controlled its hydraulic conductivity. High ionic strength caused permeable expansion of bentonite mineral layer, and absorbed a large amount of water, which reduced the porosity and changed the flow path of the fluid, resulting in an increase of hydraulic conductivity.
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Key words:
- bentonite clay liner /
- bauxite liquor /
- hydraulic conductivity /
- swell index /
- Mechanisms Controlling
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陈喜峰. 中国铝土矿资源勘查开发现状及可持续发展建议[J]. 资源与产业, 2016, 18(3):16-22. 中华人民共和国工业和信息化部. 赤泥综合利用指导意见[G/OL]. www.miit.gov.cn, 2010. POWER G, GRÄFE M, KLAUBER C. Bauxite residue issues:I. Current management, disposal and storage practices[J].Hydrometallurgy, 2011, 108(1):33-45. XUE S G, KONG X F, ZHU F, et al. Proposal for management and alkalinity transformation of bauxite residue in China[J]. Environmental Science and Pollution Res Intearch, 2016, 23(13):12822-12834. 南相莉, 张廷安, 刘燕, 等. 我国主要赤泥种类及其对环境的影响[J]. 过程工程学报, 2009, 9(1):459-464. CHEN J N, SUN C W, PENG D P, et al. The toxic elements and health impact of leachate from red mud management facilities[J]. Basic & Clinical Pharmacology & Toxicology, 2019, 124(3):30-31. 杨海朋, 白冰, 聂庆科. 赤泥渗沥液对黏性土和固化赤泥影响的试验研究[J]. 岩土力学,2017,38(增刊1):299-304. 张宏伟, 林伟岸, 詹良通, 等. 土工膜/GCL界面剪切强度特性的试验研究[J]. 岩土工程学报, 2013, 46(2):123-130. MESRI G, OLSON R. Mechanisms controlling the permeability of clays[J]. Clays and Clay Minerals, 1971,19:151-158. NORRISH K, QUIRK J. Crystalline swelling of montmorillonite, Use of electrolytes to control swelling[J]. Nature, 1954,173:255-257. CHEN J N, BRADSHAW S, LIKOS, W, et al. Hydraulic conductivity of geosynthetic clay liners to synthetic coal combustion product leachates[A]. Geo-Characterization and Modeling for Sustainability, Geotechnical Special Publication No. 234, ASCE, Reston, VA, 2014, 334-342. BRADSHAW S L, BENSON C H. Effect of municipal solid waste leachate on hydraulic conductivity and exchange complex of geosynthetic clay liners[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2014, 140(4):04013038. 介玉新, 彭涛, 傅志斌, 等. 土工合成材料黏土衬垫的渗透性研究[J]. 土木工程学报, 2009, 42(2):92-97. ASTM. Standard test methods for measurement of hydraulic conductivity of saturated porous materials using a flexible wall permeameter[S]. ASTM D5084, West Conshohocken, PA,2016. ASTM. Standard test method for measuring the exchange complex and cation exchange capacity of inorganic fine-grained soils[S]. ASTM D7503, West Conshohocken, PA,2010. ASTM. Standard test method for evaluation of hydraulic properties of geosynthetic clay liners permeated with potentially incompatible aqueous solutions[S]. ASTM D6766, West Conshohocken, PA,2012. ASTM. Standard test method for swell index of clay mineral component of geosynthetic clay liners[S]. ASTM D5890, West Conshohocken, PA,2011. TIAN K, BENSON C, LIKOS W. Hydraulic conductivity of geosynthetic clay liners to low-level radioactive waste leachate[J]. Journal of Geotechnical Geoenvironmental Engineering, 2016, 142(8):04016037. JO H, BENSON C, LEE J, et al. Long-term hydraulic conductivity of a non-prehydrated geosynthetic clay liner permeated with inorganic salt solutions[J]. J Geotech Geoenviron Eng, 2005, 10.1061/(ASCE)1090-0241(2005)131:4(405):405-417. BENSON C, OREN A, GATES W. Hydraulic conductivity of two geosynthetic clay liners permeated with a hyperalkaline solution[J]. Geotext Geomembr, 2010, 28(2):206-218. SCALIA J, BENSON C H, BOHNHOFF G L, et al. Long-term hydraulic conductivity of a bentonite-polymer composite permeated with aggressive inorganic solutions[J]. Journal of Geotechnical Geoenvironmental Engineering, 2014, 140(3):04013025. CHEN J N, BENSON C, EDIL T. Hydraulic conductivity of geosynthetic clay liners with sodium bentonite to coal combustion product leachates[J]. Journal of Geotechnical Geoenvironmental Engineering, 2018, 144(3). JO H, KATSUMI T, BENSON C, et al. Hydraulic conductivity and swelling of non-prehydrated GCLs permeated with single species salt solutions[J]. Journal of Geotechnical Geoenvironmental Engineering, 2001, 127(7):557-567. KOLSTAD D, BENSON C, EDIL T, et al. Hydraulic conductivity of a dense prehydrated GCL permeated with aggressive inorganic solutions[J]. Geosynthetics International, 2004b, 11(3):233-241. TIAN K, BENSON C H. Containing bauxite liquor Using Bentonite-Polymer Composite Geosynthetic Clay Liners[C]//Proceedings of the 8th International Congress on Environmental Geotechnics Volume 2, Springer Singapore, Singapore, 2019:672-678. CHEN J, BRADSHAW S, BENSON C, et al. pH-Dependent Leaching of Trace Elements from Recycled Concrete Aggregate, State of the Art and Practice in Geotechnical Engineering[M]. ASCE, Reston VA, 2012:3729-3738.
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