摘要
裂隙存在会导致溶液不均匀渗流,对离子型稀土原地浸出有重大影响。为探究裂隙对原地浸出溶液渗流和稀土离子浸出的影响机制,通过预设矿体裂隙结构开展室内浸出试验,探明裂隙影响下浸矿溶液非均匀渗流及稀土浸出规律。结果表明:裂隙阻碍了溶液的正常浸润,相较于无裂隙组浸润时长600 min,裂隙组浸润时长达1500 min,矿体初始浸润时间的延长降低了矿体的浸矿效率;其次,裂隙导致溶液自由流动受阻,有效渗流通道数量减少,其稳态入渗速率仅为无裂隙组的3/5;此外,无裂隙组中稀土离子的浸出率为86%,裂隙组的浸出率仅为74%,裂隙影响下稀土浸出率降低表明裂隙矿体内部存在局部浸矿盲区,影响原地浸矿过程中离子型稀土资源的高效回收。
The presence of fractures in ion-adsorbed rare earth ore significantly alters the infiltration behavior of leaching solutions,leading to uneven flow paths and reduced extraction efficiency.However,the mechanisms by which fractures affect the migration and leaching dynamics of rare earth elements remain insufficiently understood.This study aims to clarify how fractures influence leaching performance under controlled conditions.This study investigates the influence of fractures on the seepage behavior of leaching solutions and the leaching efficiency of rare earth ions during the leaching process.Using reconstructed rare earth samples,a box model was established with pre-designed fissure structures within the ore body to conduct laboratory leaching experiments.The research focuses on characterizing the non-uniform seepage patterns of the leaching solution in the presence of fractures,analyzing how fractures affect the infiltration capacity of the ore body,and elucidating the flow and distribution behavior of the leaching solution under fissure influence.Furthermore,the study reveals the governing mechanism by which fractures impact the leaching of rare earth ions.(1)In samples without fractures,the time to fully saturate the ore body was 600 min,whereas fractured samples required 1500 min,indicating that fractures delayed uniform infiltration;(2)The steady-state infiltration rate in fractured samples was 0.10 cm·min^(-1),compared to 0.06 cm·min^(-1) in non-fractured ones,suggesting that although fractures initially enhanced localized flow,they reduced overall permeability by impeding consistent diffusion;(3)The effluent discharge at the base of the fracture-free group exhibited a quasi-normal distribution,whereas a significant preferential flow phenomenon was observed in the fractured group;(4)The rare earth leaching recovery reached 86%in the non-fractured group,while the fractured group achieved only 74%.Moreover,the leaching process concluded in 104 h without fractures,whereas it extended to 144 h with fractures,implying that fractures reduce efficiency and prolong the leaching period.Fractures within the ore body lead to preferential saturation near the injection points while impeding the natural lateral flow of leaching solution into adjacent zones.As a result,before complete saturation occurs,the leaching solution is unable to exit the ore matrix effectively,and the prolonged initial infiltration phase significantly hampers overall leaching efficiency;Furthermore,the presence of fractures restricts the free flow of the solution within the ore body,reducing the number of effective seepage channels;the steady-state infiltration rate of the fractured group was only 3/5 of that in the fracture-free group,significantly reducing the overall permeability.Meanwhile,the localized discontinuities in pore structure or the geometric complexity of internal seepage channels caused by fractures result in low permeability in some ore regions,making it difficult for the solution to enter,thereby causing the solution flow in these areas to be obstructed or completely stagnant.This indicates that the internal fracture structure not only provides preferential pathways for solution infiltration but also alters the normal flow paths within the ore body.Once the main flow paths are established inside the ore body,they are difficult to change.In zones lacking effective flow paths,leachate infiltration becomes difficult,resulting in localized"leaching blind spots";In addition,internal fractures disrupt the migration of rare earth ions.Compared to the non-fractured samples,the breakthrough curves for the fractured group exhibited lower peak ion concentrations and multiple secondary peaks during the tailing stage,suggesting inconsistent and delayed ion transport.This significantly extends the leaching cycle and further diminishes extraction efficiency.The observed 14%decrease in rare earth recovery rate under fractured conditions underscores the presence of isolated,under-leached zones within the ore body.These findings demonstrate that fractures adversely affect both fluid distribution and ion mobility,ultimately compromising the effectiveness and recovery rate of in-situ leaching of ion-adsorbed rare earth resources.
作者
李立浩
胡凯建
刘一凡
叶文强
刘宇洲
王晓军
LI Lihao;HU Kaijian;LIU Yifan;YE Wenqiang;LIU Yuzhou;WANG Xiaojun(Jiangxi Provincial Key Laboratory of Safe and Efficient Mining of Rare Metal Resources,Ganzhou 341000,China;School of Resources and Environmental Engineering,Jiangxi University of Science and Technology,Ganzhou 341000,China;College of Emergency Management and Safety Engineering,Jiangxi University of Science and Technology,Ganzhou 341000,China)
出处
《有色金属(中英文)》
北大核心
2026年第2期369-380,共12页
Nonferrous Metals
基金
国家自然科学基金资助项目(52464013,52174113,51904119)
江西省国际合作重点项目(20244BDF60003)
江西理工大学清江青年英才支持计划资助项目(JXUSTQJYX2020007)。
关键词
离子型稀土矿
裂隙
入渗
不均匀渗流
稀土浸出
ionic rare earth ore
fracture
infiltration
non-uniform seepage
rare earth leaching
