背景地下水作用下铀在砂岩铀矿微界面上的扩散模式  

Diffusion patterns of uranium at the micro-interfaces between groundwater and sandstone uranium ore under the action of background groundwater

作　　者：杨迎春 丁洋 周函 丁德馨 姜瑭[1,2] YANG Yingchun;DING Yang;ZHOU Han;DING Dexin;JIANG Tang(School of Resources,Environment and Safety Engineering,University of South China,Hengyang Hunan 421001,China;Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy,University of South China,Hengyang Hunan 421001,China)

机构地区：[1]南华大学资源环境与安全工程学院,湖南衡阳421001 [2]南华大学铀矿冶生物技术国防重点学科实验室,湖南衡阳421001

出　　处：《有色金属（矿山部分）》2024年第1期107-113,共7页NONFERROUS METALS(Mining Section）

基　　金：国家自然科学基金资助项目(U1967210)。

摘　　要：上游背景地下水流入酸法地浸采铀退役采区地下水中时产生了稀释和冲洗作用。为探究背景地下水作用下酸法地浸退役采区地下水中铀在水岩微界面上的扩散模式和控制机理,开展了静态稀释实验和动态冲洗实验。静态稀释实验结果显示,背景地下水与污染地下水比例为50∶1时,1440 min内铀浓度降到背景值60μg/L以下;初期阶段(0~20 min),反应速率主要受膜扩散控制;中期阶段(20~150 min),反应速率受膜扩散和颗粒内扩散共同控制;后期阶段(150~600 min),反应速率主要受颗粒内扩散控制。动态冲洗实验结果表明,用25个孔隙体积的背景地下水,10 d内铀浓度降至50μg/L;初期阶段(0~4 d),反应速率主要受膜扩散控制;中期阶段(4~7 d),反应速率同时受膜扩散与颗粒内扩散控制;后期阶段(7~10 d),反应速率主要受颗粒内扩散控制。这些研究结果揭示了上游背景地下水流入酸法地浸采铀退役采区地下水中后铀的扩散和迁移规律,为酸法地浸采铀退役采区地下水自然净化的可行性评估提供了理论依据。The upstream background groundwater flowing into the contaminated groundwater in the decommissioned area at an acid in-situ leach uranium mine produces dilution and flushing effects.In order to investigate the diffusion patterns and related mechanisms of uranium at the micro-interfaces between groundwater and sandstone uranium ore in the decommissioned area at an in-situ leach uranium mine under the action of background groundwater,and static dilution and dynamic flushing experiments were carried out.The results of static dilution experiments showed that when the ratio of background groundwater to polluted groundwater is 50∶1,the concentration of uranium decreased below the background value of 60μg/L within 1440 min;in the early dilution period(0—20 min),the reaction rate was mainly controlled by the membrane diffusion mode;in the middle dilution period(20—150 min),the reaction rate was controlled by both membrane diffusion and intra-particle diffusion;in the late dilution period(150—600 min),the reaction rate was mainly controlled by the intra-particle diffusion mode.The results of dynamic flushing experiments showed that 25 pore volume of background groundwater decreased the concentration of uranium to 50μg/L within 10 d;in the early flushing period(0—4 d),the reaction rate was mainly controlled by the membrane diffusion mode;in the middle flushing period(4—7 d),the reaction rate was controlled by both membrane diffusion and intra-particle diffusion;in the late flushing period(7—10 d),the reaction rate was mainly controlled by the intra-particle diffusion mode.These research results revealed the diffusion and migration patterns of uranium in the groundwater after the upstream background groundwater flowed into it and provided a theoretical basis for the feasibility assessment of natural purification of uranium-contaminated groundwater.

关 键 词：酸法地浸 铀污染地下水 自然修复 微界面 膜扩散 颗粒内扩散 

分 类 号：X523[环境科学与工程—环境工程]