CO_(2)+O_(2)地浸采铀采区含铀砂岩孔隙演化试验研究  

Experimental investigate on the evolution of porosity structure in uranium⁃bearing sandstone cores within CO_(2)+O_(2)in⁃situ leaching uranium mining

作　　者：贺桂成 张沈平 扶海鹰 崔佳欣 张辉 HE Guicheng;ZHANG Shenping;FU Haiying;CUI Jiaxin;ZHANG Hui(School of Resource Environment and Safety Engineering,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

出　　处：《采矿与安全工程学报》2024年第1期179-189,共11页Journal of Mining & Safety Engineering

基　　金：国家重点研发计划项目(2021YFC2902104);国家自然科学基金项目(51974163,52274127)。

摘　　要：CO_(2)+O_(2)地浸采铀采区含铀砂岩孔隙结构演化影响了铀矿的高效浸出,已成为制约地浸采铀技术发展的瓶颈。为此,采用自制的CO_(2)+O_(2)地浸采铀试验装置,模拟了某砂岩型铀矿地浸采铀过程;并采用高压压汞仪、CT扫描仪和X射线衍射分析仪等设备表征了含铀砂岩岩芯在试验前后的孔隙演化特征;同时,运用Avizo软件构建了三维数字岩芯及其渗流模型,分析了溶浸液渗流规律。研究结果表明:试验后含铀砂岩岩芯总孔隙度和连通孔隙度与试验前相比分别增加了5.03%和5.53%;且试验后数字岩芯的逐层面孔率分布范围更广、孔喉等效半径和喉道面积急剧增大;试验后岩芯孔隙数量随孔隙配位数增大而减小,但当孔隙配位数C≥4时,试验后孔隙数量与试验前相比成倍数增长,最高达到了试验前的21.63倍,此时岩芯中连通孔隙非常显著,渗透率增大;含铀砂岩岩芯中大孔喉相互连接形成的孔隙网络为溶浸液提供了主要的渗流通道,且溶浸液的渗流速度由岩芯中心沿径向方向呈现出由大变小的规律。研究结果可为后续CO_(2)+O_(2)地浸采铀中分析溶质迁移演化规律提供有意义的参考。The evolution of porosity structure in uranium⁃bearing sandstone cores within CO_(2)+O_(2)in⁃situ leaching uranium mining has a significant impact on the efficient leaching of uranium,and it has become a bottleneck in the development of in⁃situ uranium leaching technology.This study employed a custom⁃designed CO_(2)+O_(2)in⁃situ leaching uranium test apparatus to simulate the in⁃situ uranium leaching process in a sandstone⁃type uranium deposit.Additionally,advanced equipment,including a high⁃pressure mer⁃cury porosimeter,CT scanner,and X⁃ray diffraction analyzer,was used to characterize the changes in porosity features of uranium⁃bearing sandstone core samples before and after experimentation.Further⁃more,3D digital core samples and their permeability models were created using Avizo software to ana⁃lyze the leachate fluid flow patterns.The research results indicate that after the experiments,the total po⁃rosity and connected porosity of the uranium⁃bearing sandstone core samples increased by 5.03%and 5.53%,respectively,compared to their pre⁃experiment state.The distribution range of layer⁃by⁃layer pore rates of the digital core samples was broader after the experiments,and the equivalent radius of pore throats and throat area experienced a significant increase.Additionally,the number of pores within the core samples decreased as the pore coordination number increased,but when the pore coordination num⁃ber was greater than or equal to 4,the number of pores after the experiments increased by a multiple,reaching a maximum of 21.63 times the pre⁃experiment levels.At this point,the core samples exhibited highly significant connected porosity,resulting in increased permeability.The interconnected pore net⁃work formed by large pore throats within the uranium⁃bearing sandstone core samples served as the primary fluid flow pathways for the leachate,and the leachate flow velocity displayed a pattern of decrea⁃sing from large to small along the radial direction from the core cen

关 键 词：CO_(2)+O_(2)地浸采铀 含铀砂岩 孔隙演化 数字岩芯 渗透率 

分 类 号：TD862[矿业工程—金属矿开采]