School of Resource Environment and Safety Engineering, University of South China, Hengyang, 421001, Hunan, China.
Environ Sci Pollut Res Int. 2021 Mar;28(12):15248-15258. doi: 10.1007/s11356-020-11758-0. Epub 2020 Nov 24.
The permeability characteristics of overburden soil have a significant effect on radon exhalation in uranium tailings pond. To understand this change, the effects of dry density, particle size range, and moisture content on the gas permeability and radon exhalation were studied by correlation analysis method. According to the mechanism of radon generation, the permeability characteristics of overburden, and the weather conditions, a theoretical model of radon exhalation was constructed and an experimental setup was designed. A series of tests on different properties of overburden soil were conducted by uranium tailings permeameter, and the radon exhalation rate of corresponding overburden surface was measured by local static method. Results show that the permeability of overburden decreased, which led to the decrease of radon exhalation: (1) At the same moisture content, with the increase of dry density, both the gas permeability and radon exhalation rate decrease. (2) At the same moisture content, with the increase of the particle size range, both the gas permeability and radon exhalation rate increase. (3) At the same dry density, with the increase of moisture content, the gas permeability decreases, while the radon exhalation rate increases slightly at first and then decreases.
覆盖层土壤的渗透特性对铀尾矿库氡逸出有重要影响。为了了解这种变化，采用相关分析方法研究了干密度、粒径范围和含水量对气体渗透和氡逸出的影响。根据氡的生成机理、覆盖层的渗透特性和天气条件，构建了氡逸出的理论模型，并设计了实验装置。利用铀尾矿渗透仪对不同性质的覆盖层土壤进行了一系列试验，并采用局部静态法测量了相应覆盖层表面的氡逸出率。结果表明，覆盖层的渗透率降低，导致氡逸出减少：(1) 在相同含水量下，随着干密度的增加，气体渗透率和氡逸出率均降低。(2) 在相同含水量下，随着粒径范围的增加，气体渗透率和氡逸出率均增加。(3) 在相同干密度下，随着含水量的增加，气体渗透率降低，而氡逸出率起初略有增加，然后降低。
