Uranium Mineralization and Its Radioactive Decay-Induced Carbonization in a Black Shale-Hosted Polymetallic Sulfide Ore Layer, Southwest China

Xu, Ji‐Feng; Zhu, Sanyuan; Luo, Taiyi; Zhou, Wen; Li, Yiliang

doi:10.2113/econgeo.110.6.1643

Cited by 16 publications

(5 citation statements)

References 71 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Additionally, the identification of factors affecting the dissolution of U–V bearing minerals under environmentally relevant conditions evaluated in this study is relevant to inform remediation and resource recovery initiatives in sites where these U–V bearing minerals are abundant. For instance, the results from this study have implications for other abandoned uranium mines in the Colorado Plateau, South Dakota (Black Hills), southwest China, southern Jordan, and the calcreted drainages of arid and semiarid western and southern Australia where carnotite, tyuyamunite and other U–V bearing minerals are commonly found. ,,− …”

Section: Resultsmentioning

confidence: 80%

Reactive Transport of U and V from Abandoned Uranium Mine Wastes

Avasarala¹,

Lichtner

Ali³

et al. 2017

Environ. Sci. Technol.

View full text Add to dashboard Cite

The reactive transport of uranium (U) and vanadium(V) from abandoned mine wastes collected from the Blue Gap/Tachee Claim-28 mine site in Arizona was investigated by integrating flow-through column experiments with reactive transport modeling, and electron microscopy. The mine wastes were sequentially reacted in flow-through columns at pH 7.9 (10 mM HCO3−) and pH 3.4 (10 mM CH3COOH) to evaluate the effect of environmentally relevant conditions encountered at Blue Gap/Tachee on the release of U and V. The reaction rate constants (km) for the dissolution of uranyl–vanadate (U–V) minerals predominant at Blue Gap/Tachee were obtained from simulations with the reactive transport software, PFLOTRAN. The estimated reaction rate constants were within 1 order of magnitude for pH 7.9 (km = 4.8 × 10−13 mol cm−2 s−1) and pH 3.4 (km = 3.2 × 10−13 mol cm−2 s−1). However, the estimated equilibrium constants (Keq) for U–V bearing minerals were more than 6 orders of magnitude different for reaction at circumneutral pH (Keq = 10−38.65) compared to acidic pH (Keq = 10−44.81). These results coupled with electron microscopy data suggest that the release of U and V is affected by water pH and the crystalline structure of U–V bearing minerals. The findings from this investigation have important implications for risk exposure assessment, remediation, and resource recovery of U and V in locations where U–V-bearing minerals are abundant.

show abstract

Section: Resultsmentioning

confidence: 80%

Reactive Transport of U and V from Abandoned Uranium Mine Wastes

Avasarala¹,

Lichtner

Ali³

et al. 2017

Environ. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…These results indicate that synthetic and natural minerals could experience potential discrepancies in crystal structure due to differences in hydration that could affect their rates of reaction under environmentally relevant conditions. The knowledge obtained from this study and the integrated methodology used to obtain this information can be transcribed to other mine waste sites where uranyl vanadates are dominant [7][8][9][10][11][12][13][14][15]. This information will be especially helpful in developing effective reclamation strategies that will promote the conversion of abandoned and contaminated U mines to usable land.…”

Section: Discussionmentioning

confidence: 99%

Crystal Chemistry of Carnotite in Abandoned Mine Wastes

et al. 2020

View full text Add to dashboard Cite

The crystal chemistry of carnotite (prototype formula: K2(UO2)2(VO4)2·3H2O) occurring in mine wastes collected from Northeastern Arizona was investigated by integrating spectroscopy, electron microscopy, and x-ray diffraction analyses. Raman spectroscopy confirms that the uranyl vanadate phase present in the mine waste is carnotite, rather than the rarer polymorph vandermeerscheite. X-ray diffraction patterns of the carnotite occurring in these mine wastes are in agreement with those reported in the literature for a synthetic analog. Carbon detected in this carnotite was identified as organic carbon inclusions using transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS) analyses. After excluding C and correcting for K-drift from the electron microprobe analyses, the composition of the carnotite was determined as 8.64% K2O, 0.26% CaO, 61.43% UO3, 20.26% V2O5, 0.38% Fe2O3, and 8.23% H2O. The empirical formula, (K1.66Ca0.043Al(OH)2+0.145 Fe(OH)2+0.044)((U0.97)O2)2((V1.005)O4)2·4H2O of the studied carnotite, with an atomic ratio 1.9:2:2 for K:U:V, is similar to the that of carnotite (K2(UO2)2(VO4)2·3H2O) reported in the literature. Lattice spacing data determined using selected area electron diffraction (SAED)-TEM suggests: (1) complete amorphization of the carnotite within 120 s of exposure to the electron beam and (2) good agreement of the measured d-spacings for carnotite in the literature. Small differences between the measured and literature d-spacing values are likely due to the varying degree of hydration between natural and synthetic materials. Such information about the crystal chemistry of carnotite in mine wastes is important for an improved understanding of the occurrence and reactivity of U, V, and other elements in the environment.

show abstract

“…Natural U ore with a U content of 8748 μg/g was used to enhance neutron-induced natural decays. All of the rock, kerogen, and U ore samples were crushed to the needed fineness (<75 μm in size), for the observed range of the radiation effects in rock and OM were within 75 μm …”

Section: Methodsmentioning

confidence: 99%

“…Approximately 90% of the natural radiation dose comes from α decay, and the remaining radiation dose comes mostly from β decay . Radiation has been found to have an effect within a semidiameter of ∼75 μm, similar to penetration depth of α particles (<100 μm), much shorter than that of β (1–5 mm) and γ (>50 m). Positive relationships between the δ 13 C org with natural U decay ,, and artificial radiation of α particles has been found, while not for γ .…”

Section: Introductionmentioning

confidence: 99%

Oil Generation from the Immature Organic Matter after Artificial Neutron Irradiation

et al. 2019

View full text Add to dashboard Cite

Organic-rich shale often receives high doses of radiation from radionuclides, mostly uranium (U). Natural decay of U releases particles and energy simultaneously. Thermal stress is considered to be conducive to organic matter (OM) maturation and petroleum generation and has always been taken into account in the simulation of basin thermal evolution. However, for the particles and their bombardment, the effect is still unclear. The main reason is that the half-life of U is up to 4.5 billion years; it is impossible to monitor the effect of U natural decay in the laboratory. Here, we implemented a thermal neutron irradiation experiment in a nuclear reactor using immature Type-II organic matter, to activate and accelerate the natural decay of U. Radiogenic heat was designed to be removed with the circulating water at room temperature to reduce the potential effect of thermal degradation. Oil generated from the irradiated organic matter confirmed that particle bombardment from the U natural decay promoted oil production, with a maximum yield of 19.5 mg g −1 TOC. The oil produced was rich in asphaltene, aromatic compounds, and high-molecular-weight compounds, and also had abundant low-maturity and intermediate products (e.g., alkenes, prist-1-ene, C 27 -hop-17(21)-ene, and moretanes) in the saturated fraction. These results indicated that particle bombardment led to the radiolytic cracking of C−C bonds, different from the traditional thermal degradation processes. Therefore, as a function of time and content, the natural irradiation from U decay should be taken into account, when evaluating the petroleum resources of Paleozoic and Proterozoic U-rich source rocks.

show abstract

Uranium Mineralization and Its Radioactive Decay-Induced Carbonization in a Black Shale-Hosted Polymetallic Sulfide Ore Layer, Southwest China

Cited by 16 publications

References 71 publications

Reactive Transport of U and V from Abandoned Uranium Mine Wastes

Reactive Transport of U and V from Abandoned Uranium Mine Wastes

Crystal Chemistry of Carnotite in Abandoned Mine Wastes

Oil Generation from the Immature Organic Matter after Artificial Neutron Irradiation

Contact Info

Product

Resources

About