Mineralogy and geochemistry of carbonate cement in sandstone and implications for mineralization of the Qianjiadian sandstone-hosted uranium deposit, southern Songliao Basin, China

In situ leaching (ISL) is becoming the main mining practice for sandstone-type uranium deposits in China. The key to ISL technology is to aid the leaching solution in contacting the ore bed over a large range, which will induce a series of chemical reactions to extract uranium; thus, it is essential to thoroughly understand the reservoir physical properties of uranium deposits. Taking the Qianjiadian sandstone-type uranium deposits (southern Songliao Basin, China) as an example, the mineral composition and pore structure of samples in different layers were measured using X-ray diffraction (XRD), thin section analysis (TSA), low-temperature N2 adsorption (LTN2A), and mercury intrusion porosimetry (MIP), and their influences on the ISL effect were analyzed. The results show that more than 65% of the minerals in the Qianjiadian uranium deposits are felsic minerals, and the carbonate minerals, clay minerals, and augite are auxiliary minerals. The primary intergranular pores, intergranular-dissolved pores, intragranular-dissolved pores, intercrystalline pores, and microfractures are developed in uranium deposits with various lithologies to different degrees. The macropores ( >1000 nm) and mesopores (100-1000 nm) of medium sandstone, argillaceous sandstone, and siltstone are well developed; in contrast, the proportions of micropores ( <10 nm) and transition pores (10-100 nm) in coarse sandstone, fine sandstone, and sandy mudstone are quite high. The heterogeneity of pores in uranium deposits of different lithologies is strong and influences the mineral composition and its fabric mode. Coarse sandstone, fine sandstone, and sandy mudstone are favorable for ISL mining in Qianjiadian uranium deposits because their permeability is above the required permeability threshold of ISL. The uranium deposits with permeability below the threshold are recommended to adopt the blasting-enhanced permeability method to improve their permeability for achieving large-scale and high-efficiency ISL mining. This study can provide guidance for the selection of favorable ore beds for ISL mining and reservoir stimulation methods in low-permeability sandstone-type uranium deposits.

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“…After the test, the mineral compositions were obtained by profile fitting of the scattering curve. Sixth member [36]). 4 Geofluids…”

Section: Experimental Methodmentioning

confidence: 99%

Mineral Composition and Full-Scale Pore Structure of Qianjiadian Sandstone-Type Uranium Deposits: Application for In Situ Leaching Mining

et al. 2022

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“…Under the action of oxygenated meteoric precipitation, Cdcontaining minerals in source rocks such as sphalerite are prone to dissolution and oxidation [47], forming oxides such as CdO or CdSO 4 that enter oxygenated ore-forming fluids for relatively long-distance transport along permeable sandstones. Polarizing microscope and scanning electron microscope observations show that carbonate cements including dolomite, ankerite, calcite, and siderite are developed in the sandstones of the oxidation and transition zones of the Yaojia Formation [12,14,48]. Hydrocarbons from the source rocks of the Jiufotang (K1j) Formation acted as reductants [5,9], generating a large amount of CO 2 that was expected to participate in carbonate cementation [13].…”

Section: Cadmium (Cd)mentioning

confidence: 99%

“…Otavite and siderite have similar chemical properties and forming conditions and often occur as paragenetic minerals [47]. The siderite content in the transition and oxidation zones of the Qianjiadian uranium deposit was both low but approximately equal [48]. However, the degree of cadmium enrichment in the transition zone is much higher than that in the oxidation zone.…”

Section: Cadmium (Cd)mentioning

confidence: 99%

Geochemical Characteristics of Trace Elements and REEs and their Geological Significance for Uranium Mineralization within the Qianjiadian Sandstone-Hosted Uranium Deposit, Songliao Basin

Yan

Guo

et al. 2023

Geofluids

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The Qianjiadian uranium deposit is a typical interstratified oxidized zone sandstone-hosted uranium deposit hosted in the Upper Cretaceous Yaojia Formation of the southern Songliao Basin. Despite its significance, little research has been conducted on the relationship between trace elements, REEs, and uranium mineralization in this deposit. This study presents new geochemical data from sandstones in the oxidation, transition, and reduction zones. The sandstones in the transition zone are highly enriched in U and moderately enriched in Mo, Cd, and V compared to those in the oxidation and reduction zones. They are also weakly enriched in Co, Ni, and Zn. The oxidation and transition zone sandstones have higher ∑LREE and ∑HREE contents than those in the reduction zone. However, the oxidation zone sandstones are characterized by LREE enrichment and flat HRRE distribution, while the transition zone sandstones show HRRE enrichment and flat LREE distribution. These trace element and REE differentiation characteristics within each subzone are closely related to the geological process of interstratified oxygenation. Oxygenated uranium-bearing fluids from southwestern provenance areas carried multiple trace elements and REEs and infiltrated along the oxidation sandstones to reach the Yaojia Formation’s transition zone. During this process, a certain amount of Mo, V, Cd, and LREE from the oxygenated ore-forming fluids was precipitated by Fe-Mn hydroxide adsorption or calcite and siderite cementation. Meanwhile, about 20.33% of preexisting U in the oxidation zone sandstones was continuously extracted and entered into the oxygenated ore-forming fluids. In the transition zone, where dissolved oxygen was exhausted and hydrocarbons were continuously injected, U, Mo, Cd, V, Co, Ni, Zn, and REEs were unloaded and precipitated as uranium minerals, sulfide minerals, or carbonate minerals. The enrichment of Mo, Cd, V, and HREEs in the sandstones can serve as new prospecting indicators for the Qianjiadian uranium deposit.

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“…In recent decades, extensive research has been conducted primarily regarding the mineralization processes of sandstone-type uranium deposits (Yue et al 2011;Zhao et al 2018;Jia et al 2020), where the CO 2 ? O 2 in-situ leaching uranium represents the reverse process of mineralization.…”

Section: Chemical Reactionsmentioning

confidence: 99%

Quantifying the impact of mineralogical heterogeneity on reactive transport modeling of CO2 + O2 in-situ leaching of uranium

et al. 2021

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CO 2 ? O 2 in-situ leaching (ISL) of sandstonetype uranium ore represents the third generation of solution mining in China. In this study, reactive transport modeling of the interaction between hydrodynamic and geochemical reactions is performed to enable better prediction and regulation of the CO 2 ? O 2 in-situ leaching process of uranium. Geochemical reactions between mining solutions and rock, and the kinetic uranium dissolution controlled by O 2 (aq) and bicarbonate ( HCO À3 ) are considered in the

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Mineralogy and geochemistry of carbonate cement in sandstone and implications for mineralization of the Qianjiadian sandstone-hosted uranium deposit, southern Songliao Basin, China

Cited by 19 publications

References 31 publications

Mineral Composition and Full-Scale Pore Structure of Qianjiadian Sandstone-Type Uranium Deposits: Application for In Situ Leaching Mining

Mineral Composition and Full-Scale Pore Structure of Qianjiadian Sandstone-Type Uranium Deposits: Application for In Situ Leaching Mining

Geochemical Characteristics of Trace Elements and REEs and their Geological Significance for Uranium Mineralization within the Qianjiadian Sandstone-Hosted Uranium Deposit, Songliao Basin

Quantifying the impact of mineralogical heterogeneity on reactive transport modeling of CO2 + O2 in-situ leaching of uranium

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