Geochemical reactions altering the mineralogical and multiscale pore characteristics of uranium-bearing reservoirs during CO2 + O2 in situ leaching

Frontiers in Earth Science

Earth Science

Xuebin Su¹  Lixin Zhao¹  Genmao Zhou¹  Qinghe Niu²  Xingyu Zhou²  Beibei Sun²  Jianhui Zhang²  Wei Wang²  Qizhi Wang³  Zhongmin Ji⁴  Xiaofei Qi⁵  Lanlan Tian⁵ 

[1] Department of In Situ Leaching Technology, Beijing Research Institute of Chemical Engineering and Metallurgy, Beijing, China;Key Laboratory of Roads and Railway Engineering Safety Control, Ministry of Education (Shijiazhuang Tiedao University), Shijiazhuang, China;State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures, Shijiazhuang Tiedao University, Shijiazhuang, China;Hebei Technology and Innovation Center on Safe and Efficient Mining of Metal Mines, Shijiazhuang, China;School of Civil Engineering, Hebei University of Science and Technology, Shijiazhuang, China;Innovation Center of Disaster Prevention and Mitigation Technology for Geotechnical and Structural Systems of Hebei Province (Preparation), Shijiazhuang, China;School of Civil Engineering, Zhengzhou University of Technology, Zhengzhou, China;The Second Geological Team of Hebei Coalfield Geology Bureau, Xingtai, China;

关键词: CO + O–water–rock geochemical reaction;    pore size distribution;    fractal characteristic;    mineral dissolution and precipitation;    pore throat;   

DOI  :  10.3389/feart.2022.1094880

 received in 2022-11-10, accepted in 2022-12-09,  发布年份 2023

来源: Frontiers

【 摘 要 】

CO2 + O2 in situ leaching has been extensively applied in uranium recovery in sandstone-type uranium deposits of China. The geochemical processes impact and constrain the leaching reaction and leaching solution migration; thus, it is necessary to study the CO2 + O2–water–rock geochemical reaction process and its influence on the physical properties of uranium-bearing reservoirs. In this work, a CO2 + O2–water–rock geochemical reaction simulation experiment was carried out, and the mineralogical and multiscale pore characteristics of typical samples before and after this simulation experiment were compared by X-ray diffraction and high-pressure mercury intrusion porosimetry (HPMIP). The results show that the CO2 + O2–water–rock geochemical reaction has complicated effects on the mineral compositions due to the various reaction modes and types. After the CO2 + O2–water–rock geochemical reaction, the femic minerals decrease and the clay minerals in the coarse sandstone, medium sandstone, fine sandstone, and siltstone increase, while the femic minerals and clay minerals in sandy mudstone show a contrary changing trend. The CO2 + O2–water–rock geochemical reaction decreases the total pore volume of uranium-bearing reservoirs and then promotes pore transformation from small scale to large scale. The fractal dimensions of macropores are decreased, and the fractal dimensions of mesopores, transition pores, and micropores are increased. The effects of felsic mineral and carbonate dissolution, secondary mineral precipitate, clay mineral swelling, and mineral particle migration are simultaneously present in the CO2 + O2 in situ leaching process, which exhibit the positive transformation and the negative transformation for the uranium-bearing reservoirs. The mineral dissolution may improve reservoir permeability to a certain degree, while the siltation effect will gradually reveal with the extension of CO2 + O2 in situ leaching. This research will provide a deep understanding of the physical property response of uranium-bearing reservoirs during CO2 + O2 in situ leaching and indicate the direction for the efficient recovery of uranium resources.

【 授权许可】

Unknown   
Copyright © 2023 Zhou, Wang, Niu, Wang, Su, Zhou, Zhao, Ji, Qi, Tian, Zhang and Sun.