相山铀矿尾矿区酸性矿山排水和沉积物稀土元素地球化学特征  

Geochemical characteristics of rare earth elements in acid mine drainage and sediments from the Xiangshan uranium mine tailings area

作　　者：张一帆 刘海燕 董姝 郭华明[3] 王振 孙占学[1,2] 周仲魁[1,2] ZHANG Yifan;LIU Haiyan;DONG Shu;GUO Huaming;WANG Zhen;SUN Zhanxue;ZHOU Zhongkui(State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang 330032,China;Jiangxi Provincial Key Laboratory of Genesis and Remediation of Groundwater Pollution,East China University of Technology,Nanchang 330032,China;School of Water Resources and Environment,China University of Geosciences(Beijing),Beijing 100083,China)

机构地区：[1]东华理工大学核资源与环境国家重点实验室,江西南昌330032 [2]东华理工大学地下水污染成因与修复江西省重点实验室,江西南昌330032 [3]中国地质大学(北京)水资源与环境学院,北京100083

出　　处：《地学前缘》2025年第2期412-429,共18页Earth Science Frontiers

基　　金：国家自然科学基金项目(42262029,42302284);江西省自然科学基金项目(20232BAB203066,20232BAB213068);江西省重点研发计划项目(20212BBG71011)。

摘　　要：酸性矿山排水(AMD)因化学毒性和生态环境危害受到世界广泛关注。本文以相山铀矿尾矿排水及其下游沉积物为研究对象,沿矿山排水排泄方向采集了22个AMD和31个沉积物样品,通过室内室外试验综合分析,探究了AMD和沉积物中稀土元素(REEs)的含量和分异特征及其控制因素。研究表明,AMD的pH为3.65~6.24(平均值4.51),水化学类型为单一的SO_(4)^(2-)Ca型水,REEs浓度总量(ΣREEs)为0.41~191.23μg/L(平均值80.32μg/L),pH值与ΣREEs浓度呈负相关关系,是控制REEs浓度的重要因素;PHREEQC模拟显示,水中REEs以SO_(4)^(2-)络合态和自由态为主(>99%);上陆壳(UCC)归一化结果显示,水样呈重稀土元素(HREEs)相对于轻稀土元素(LREEs)富集,Ce负异常。沉积物ΣREEs含量为170.58~1259.18μg/g,随深度增加,ΣREEs含量逐渐递减;浅层沉积物具有与水样相似的HREEs富集归一化模式;尾矿内沉积物HREEs富集程度比下游沉积物更加显著;尾矿库下游沉积物随采样深度的增加,HREEs富集程度逐渐减弱,最后演变成平坦型或LREEs归一化模式。沉积物硫酸(1∶40)酸浸试验结果显示,浸出液REEs归一化模式与酸性排水相似,为HREEs富集。指示在矿山酸水形成过程中,HREEs优先于LREEs进入水体中,浅层沉积物继承了矿山酸水REEs含量特性。但是,REEs由表层往深部迁移的过程中发生了分异,HREEs相对于LREEs优先迁移,导致沉积物REEs分布模式在垂向上具有明显的演化趋势。本研究成果对铀矿山环境演化及水土污染防治具有重要意义。Acid mine drainage(AMD)has garnered global attention due to its chemical toxicity and ecological hazards.This study investigates the geochemistry of AMD and sediments in the Xiangshan uranium mine tailings area,focusing on the concentrations and fractionations of rare earth elements(REEs)and their controlling factors.A total of 22 AMD samples and 31 sediment samples were collected along the flow direction of AMD for field and laboratory analysis.The pH of AMD ranged from 3.65 to 6.24,with an average of 4.51,and the hydrochemical type was predominantly SO 2-4 Ca.Total REE concentrations(ΣREEs)in AMD varied between 0.41 and 191.23μg/L,with an average of 80.32μg/L.A negative correlation was observed between pH andΣREEs concentration,indicating that pH plays a critical role in controlling REE concentrations.Hydrogeochemical modeling using PHREEQC revealed that REEs in AMD primarily exist as SO_(4)^(2-) complexes and free ions(>99%).Upper continental crust(UCC)normalization showed that AMD was enriched in heavy REEs(HREEs)relative to light REEs(LREEs),with a negative Ce anomaly.In sediments,ΣREEs concentrations ranged from 170.58 to 1259.18μg/g and decreased with increasing depth.Shallow sediments exhibited HREE-enriched patterns similar to those of AMD samples.Sediments from the tailings pond showed a higher degree of HREE enrichment compared to sediments downstream of the tailings pond.However,with increasing depth,the HREE enrichment in downstream sediments gradually weakened,and UCC-normalized patterns evolved into relatively flat or even LREE-enriched patterns.A sulfuric acid leaching test(1∶40)on sediments revealed that the leachate exhibited REE patterns similar to AMD,with HREEs preferentially mobilized into solution compared to LREEs.This indicates that shallow sediments readily inherit the REE signatures of AMD.However,vertical migration to deeper sediment layers resulted in REE fractionation,with HREEs preferentially mobilized over LREEs,leading to a distinct vertical evolution in sediment REE patte

关 键 词：酸性矿山排水 稀土元素 异常富集 相山铀矿田 人为活动 

分 类 号：P641.3[天文地球—地质矿产勘探] P618.7[天文地球—地质学] TD167[矿业工程—矿山地质测量]