板集煤矿地下水稀土元素地球化学特征

Geochemical characteristics of rare earth elements in groundwaterof Banji Coal Mine

稀土元素具有稳定且相似的地球化学性质,被广泛用于研究地下水体与含水层之间的相互作用和地球化学过程。以淮南煤田板集煤矿为研究区,采集了砂岩水、太灰水和采空区混合水等地下水样,并对这些水样的稀土元素含量和常规水化学离子进行了测试分析,以研究矿区地下水的水化学特征、稀土元素含量分布特征以及相关控制因素等方面的内容。研究结果表明:矿区地下水中的Na^(+)+K+、Cl^(-)、HCO_(3)-平均质量浓度分别为669.1、820.3、344.0 mg/L,水质类型主要为Cl-Na、Cl·HCO_(3)-Na、HCO_(3)-Na型。研究区地下水中的稀土元素含量总体处于较低的浓度范围,其中三个混合水样中出现了重稀土的富集现象,大部分水样则呈现轻稀土富集。其中,Eu的含量最高,这是由于Eu与钙矿物的结晶沉淀作用导致其从稀土元素中分离出来。通过相关性冗余分析发现,研究区地下水样中的Eu和Fe存在一定的线性关系,说明Fe氧化物与稀土元素的吸附作用是影响稀土元素含量的重要控制因素之一。本研究对于深入了解淮南煤田板集煤矿地下水体系中的地球化学过程具体重要意义,并为矿区地下水的评价和管理提供了科学依据。

Rare earth elements possess stable and similar geochemical properties,making them widely utilized in the study of groundwater-aquifer interactions and geochemical processes.In this study,taking the Banji Coal Mine in the Huainan Coalfield as the research area,water samples including sandstone water,gray overburden water,and mixed water from mined-out areas were collected.These samples were tested and analyzed for their rare earth element contents,as well as conventional water chemistry ions.The objective was to investigate the hydrochemical characteristics of groundwater in the mining area,the distribution of the rare earth element as well as the related controlling factors.The results showed that the average mass concentrations of Na^(+)+K^(+),Cl^(-),and HCO_(3)^(-) in the groundwater of the mining area were determined to be 669.1,820.3,and 344.0 mg/L,respectively.Based on the water quality types,we classified the groundwater primarily into Cl-Na type,Cl-HCO_(2)-Na type,and HCO_(2)-Na type.Generally,the rare earth element contents in the groundwater fell within a lower concentration range.However,three mixed water samples exhibited significant enrichment of heavy rare earth elements,while most of the water samples demonstrated light rare earth enrichment.Notably,Eu displayed the highest content,primarily due to its separation from the rare earth element group during crystallization and precipitation with calcium minerals.Correlation redundancy analysis unveiled a linear relationship between Eu and Fe in the groundwater samples of the area.The adsorption of Fe oxides with rare earth might be a significant controlling factor influencing the rare earth element content.This study is of significance to a comprehensive understanding of the geochemical processes in the groundwater system of the Banji Coal Mine in the Huainan Coalfield.Furthermore,it provides a scientific basis for the evaluation and management of groundwater in the mining areas.