铀尾矿充填体氡析出规律理论研究  

Theoretical study on the radon exhalation in the uranium tailings backfill

作　　者：范楠彬 叶勇军[1] 李志[1] 赵娅利 江俊廷 

机构地区：[1]南华大学环境保护与安全工程学院,湖南衡阳421001

出　　处：《安全与环境学报》2015年第2期236-239,共4页Journal of Safety and Environment

基　　金：国家自然科学基金项目(11105069);南华大学研究生科研创新项目(2013xcx03)

摘　　要：堆浸铀尾矿用作地下充填法采场的充填料是处理铀尾矿的一种方法。将铀尾矿作为充填料时,其内残留的镭衰变产生的氡气会从其表面析出,污染井下作业环境。基于氡在介质中纯扩散的理论,研究了在尾矿介质孔隙率为0.3、铀尾矿中镭活度浓度为3 400 Bq/kg、干燥时铀尾矿的射气系数为0.1、铀尾矿的密度为2.5×103kg/m3的条件下,含水饱和度、孔隙率、覆盖层厚度等物理参数对铀尾矿充填体氡析出的影响规律。结果表明：无覆盖层时,含水饱和度在0~0.25的范围内,随含水饱和度增加,铀尾矿介质表面氡析出率先增加后减小,含水饱和度从0增加到0.12时,铀尾矿介质表面氡析出率从5 Bq/（m2·s）增加到11 Bq/（m2·s）,含水饱和度从0.12增加到0.25时,铀尾矿介质表面氡析出率从11 Bq/（m2·s）减小到10.5 Bq/（m2·s）;有覆盖层时,铀尾矿介质厚度为3 m,添加孔隙率为0.05的覆盖层,当覆盖层厚度从0增加到0.1 m时,介质表面氡析出率减小67.5%,当覆盖层厚度增加到0.5 m时,介质表面氡析出率减小91.8%。The paper is attempting to make a theoretical study on the radon exhalation in the uranium toilings backfill ground. As is done in the uranium mining practice, heap-leaching uranium railings can be used as the filling material in the stopes to deal with the uranium railings, which can not only help to reduce the pollution to the envi- ronment caused by the uranium tailings that pile on the ground-sur- face, but also can help to increase the security of the underground mined-out areas. In addition, when the uranium tailings are used as filling materials, the radon tends to decay from the residual radium in the tailings and exhale from its surface, which is likely to cause the pollution of the underground working environment. In order to ensure the security of the radiation environment to the underground workers, it is of a great urgency to study the migration regularity and the con- trol measures of radon in the radium mine. It is just starting from this need that we have worked out the formulas and equations to calculate the radon exhalation rate on the surface of the filling system. What is more important, we have been trying to use the pure diffusion theory of radon in the media as two different situations. And, then, we have made an exploration of the effects of different physical parameters, including the water saturation, porosity and layer thickness on the radon exhalation of uranium tailings, under the conditions with the railings medium porosity being 0. 3. Besides, we have also made an assessment that the radium activity concentration in the uranium tail- ings is 3 400 Bq/kg, whereas the dry uranium tailings emanation co- efficient is 0.1 with the density of uranium tailings being 2.5 × 103 kg/m3 . As is shown in the results of our study, the emanation coeffi- cient with no cover of the water saturation may tend to increase from 0 to O. 25. Furthermore, the radon exhalation of uranium tailings has been found increasing first and then decreasing. Specifically speak- ing, when the water saturation increas

关 键 词：环境工程学 铀尾矿 充填法 氡运移 覆盖层 

分 类 号：X591[环境科学与工程—环境工程]