离子吸附型稀土矿区硫酸铵原位浸矿与淋洗过程的室内模拟  

Indoor Simulation of the In-situ Ammonium Sulphate Leaching and Rainwater Leaching Processes in the Ion-adsorption Rare Earth Mining Area

作　　者：高震国 周铭 奚高胜 杨晓英[1] 王梓萌[1] GAO Zhenguo;ZHOU Ming;XI Gaosheng;YANG Xiaoying;WANG Zimeng(Department of Environmental Science and Engineering,Fudan University,Shanghai 200433,China)

机构地区：[1]复旦大学环境科学与工程系,上海200433

出　　处：《复旦学报（自然科学版）》2024年第1期134-142,共9页Journal of Fudan University：Natural Science

基　　金：国家重点研发计划(2019YFC1805100)。

摘　　要：离子吸附型稀土尾矿中残留的大量硫酸铵浸矿剂随雨水淋滤进入周边环境,可造成矿区及周边土壤和水体严重污染。本研究通过实地采集稀土矿区土壤,开展室内一维土柱实验分别模拟浸矿过程和淋洗过程,并建立Hydrus-1D模型,评价该模型对稀土矿浸矿和淋洗过程的模拟性能。Hydrus-1D模型的弥散度的率定值为0.5 cm,浸矿与淋洗过程的K d的率定值分别为0.07 cm^(3)/g和1.2 cm^(3)/g;在浸矿过程模拟中,4个观测孔模型的R^(2)为0.95~0.99,E_(RMS)为1.3~6.8 mmol/L;淋洗过程的R^(2)为0.93~0.98,E_(RMS)为0.2~1.6 mmol/L;Hydrus-1D能够较好模拟浸矿和淋洗过程中NH_(4)^(+)的迁移行为。示踪实验中Cl^(-)穿透耗时为30~90 min;浸矿实验中,4个观测孔达到吸附饱和耗时为60~150 min;淋洗实验中,4个观测孔的NH_(4)^(+)浓度低于检测限的耗时为360~540 min;土壤吸附作用对浸矿与淋洗过程中NH+4运移过程的影响显著。A large amount of ammonium sulfate leaching agent has remained in ion-adsorption rare earth tailings,which could leach into the ambient environment with rainwater and subsequently pollute surrounding soils and water bodies seriously.Using the soils collected from the rare earth mining area,we have conducted one-dimensional indoor soil column experiments to simulate in-situ ammonium sulfate leaching as well as rain water leaching processes.Hydrus-1D model was then established to evaluate its performance in simulating both processes in the rare earth mining area.In the Hydrus-1D model,dispersivity was calibrated to be 0.5 cm,whereas the K d of ammonium sulphate leaching and rainwater leaching processes was 0.07 cm^(3)/g and 1.21 cm^(3)/g,respectively.In simulating the ammonium sulphate leaching progress R^(2) and root mean square error(E_(RMS))ranged from 0.95 to 0.99 and from 1.3 to 6.8 mmol/L respectively at the four observation holes.In rainwater leaching processes,R^(2) and E_(RMS) respectively ranged from 0.93 to 0.98 and 0.21.6 mmol/L.This indicated that Hydrus-1D is capable of satisfactorily simulating the migration behavior of ammonium ions during both ammonium sulphate leaching and rainwater leaching processes.In the tracer experiment,the Penetration time of Cl^(-)was 3090 min,and in the leaching experiment,the absorption saturation time of the four observation holes was 60150 min.In rain leaching experiment,it takes 360540 min for the concentration of ammonium ions in four observation holes to be below the detection limit.Soil adsorption has a significant influence on the transport process of ammonium ions in leaching and rain leaching.

关 键 词：离子吸附型稀土矿 硫酸铵 迁移行为 土柱实验 Hydrus 

分 类 号：X53[环境科学与工程—环境工程]