Enrichment of Nb-Ta-Zr-W-Li in the Late Carboniferous Coals from the Weibei Coalfield, Shaanxi, North China

Mineralogical and geochemical characteristics of coals provide crucial information on their potential clean, efficient, and integrated utilization. In this paper, the mineralogical and geochemical behaviors of the No. 5 coals of the Taiyuan Formation in the Weibei Coalfield, North China, were investigated, and their geological controlling factors were subsequently discussed. The minerals in the Weibei coals mainly consist of kaolinite (8.3%), calcite (5.0%), and pyrite (3.1%), with minor proportions of tobelite (2.9%), dolomite (1.7%), quartz (1.8%), and traces of siderite (0.4%) and gypsum (0.6%). Several critical elements, including Nb (19.8 mg/kg), Ta (3.6 mg/kg), Zr (71.0 mg/kg) and Li (32.3 mg/kg), occur at concentrations higher than those averages for world hard coals, making the Weibei coals potential sources of these critical elements. Several factors, terrigenous material, seawater invasion, and hydrothermal fluids are responsible for these mineralogical and geochemical characteristics. The L-type rare earth elements and yttrium (REE-Y) enrichment in the roofs and partings, Al2O3-TiO2 and Zr/TiO2-Nb/Y plots, and negative Eu and weak negative Ce anomalies in the Weibei coals indicate a felsic-intermediate dominated sediment provenance primarily derived from the Qilian-Qinling Oldland on the South. Marine bioclastic limestone, negative Ce and positive Y anomalies in coals imply the influence of seawater on the Weibei coals. Last but not least, the cleat-infilling and/or fracture-infilling calcite, pyrite, barite, and tobelite as well as the positive Eu and Gd anomalies, H-type, and M-type REE-Y enrichment patterns suggest the influence of hydrothermal fluids, which lead to re-distribution of some critical elements from roof and parting to the underlying coal seam.

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Enrichment of Li–Ga–Zr–Hf and Se–Mo–Cr–V–As–Pb Assemblages in the No. 11 Superhigh Organic Sulfur Coal from the Sangshuping Coal Mine, Weibei Coalfield, Shaanxi, North China

Energies ◽

10.3390/en13246660 ◽

2020 ◽

Vol 13 (24) ◽

pp. 6660

Author(s):

Jing Li ◽

Peng Wu ◽

Guanghua Yang ◽

Lei Pan ◽

Xinguo Zhuang ◽

...

Keyword(s):

Sulfur Content ◽

Coal Mine ◽

North China ◽

Negative Impact ◽

Hydrothermal Activity ◽

Depositional Environments ◽

Hydrothermal Fluids ◽

Organic Sulfur ◽

Sediment Provenance ◽

High Sulfur Content

Superhigh organic sulfur(SHOS) coals have currently attracted great attention due to their typical depositional environments and formation history as well as their great negative impact on the ecosystem. This study investigated the geochemistry of the No. 11coalof the Late Carboniferous Taiyuan Formation from the Sangshuping coalmine, Hancheng miningarea, Weibei coalfield, Shaanxi, North China. The No. 11 coal is a high-sulfur coal with a large proportion of organic sulfur content (3.7 to 5.5%, avg. 4.4%) and belongs to typical SHOS coal. The high sulfur content in the Sangshuping coal mine has been mainly caused by the combined influences of seawater and hydrothermal fluids. The SHOS in No. 11 coal was formed in the Fe-poor and S-rich high-marine influenced occlusive environment. During the late coalification stage, a high proportion of pyritic sulfur was formed due to sufficient Fe supply from the Fe–S-rich epigenetic hydrothermal fluids. The No. 11 SHOS coal is enriched in Li–Ga–Zr–Hf and Se–Mo–Cr–V–As–Pb element assemblages. The sediment provenance of the Sangshuping coal mine is predominantly felsic–intermediate rocks from both the Yinshan and Qinling Oldland. However, the elevated concentrations of critical elements (Li, Ga, Zr, and Hf) in the No. 11 coal are primarily inherited from the Yinshan Oldland. The enrichment of the Se–Mo–Cr–V–As–Pb assemblage in No. 11 coal can be ascribed to the influence of both seawater and epigenetic hydrothermal activity.

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Geochemical characteristics and mechanism of organic matter accumulation of marine-continental transitional shale of the Lower Permian Shanxi Formation, southeastern Ordos Basin, North China

Journal of Petroleum Science and Engineering ◽

10.1016/j.petrol.2021.108815 ◽

2021 ◽

pp. 108815

Author(s):

Bangsheng Zhao ◽

Rongxi Li ◽

Xiaoli Qin ◽

Ning Wang ◽

Wei Zhou ◽

...

Keyword(s):

Organic Matter ◽

North China ◽

Ordos Basin ◽

Geochemical Characteristics ◽

Lower Permian ◽

Organic Matter Accumulation

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Acquisition and Quantification of Main Controlling Factors of Water Inrush from Coal Seam Floor in Coalfields of North China

Research on Risk Evaluation Methods of Groundwater Bursting from Aquifers Underlying Coal Seams and Applications to Coalfields of North China - Springer Theses ◽

10.1007/978-3-319-79029-9_3 ◽

2018 ◽

pp. 49-70

Author(s):

Yifan Zeng

Keyword(s):

Coal Seam ◽

North China ◽

Water Inrush ◽

Controlling Factors ◽

Main Controlling Factors

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The Distribution of Rare Metals in the LCT Pegmatites from the Giraúl Field, Angola

Minerals ◽

10.3390/min9100580 ◽

2019 ◽

Vol 9 (10) ◽

pp. 580

Author(s):

Gonçalves ◽

Melgarejo ◽

Alfonso ◽

Amores ◽

Paniagua ◽

...

Keyword(s):

Grain Size ◽

Hydrothermal Fluids ◽

Granitic Pegmatite ◽

Rare Metals ◽

Accessory Minerals ◽

Critical Elements ◽

Incompatible Elements ◽

Pegmatite Body ◽

Quartz Core ◽

Oxide Minerals

The Giraúl granitic pegmatite field in Angola is composed of five pegmatite types, the most evolved belong to the beryl-columbite, beryl-columbite-phosphate and spodumene types. Pegmatites are concentrically zoned with increased grain size toward a quartz core; the most evolved pegmatites have well-developed replacement units. These pegmatites are rich in Nb-Ta oxide minerals and the field has a moderate interest for critical elements such as Ta and Hf. Tourmaline, garnet and micas occur as accessory minerals. The abundance of Zr and Nb-Ta minerals increases with the evolution of the pegmatites, as well as the proportions of beryl and Li-rich minerals. The Ta/(Ta + Nb) ratio in Nb-Ta oxide minerals and the Hf/(Hf + Zr) ratio in zircon also increase with the evolution of the pegmatites and within each pegmatite body from border to inner zones, and especially in the late veins and subsolidus replacements. Textural patterns and occurrence of late veins with Ta-rich minerals suggest that Nb and especially Ta can be enriched in late hydrothermal fluids exsolved from the magma, along with Hf and other incompatible elements as Sn, U, Pb, Sb and Bi.

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Sandstone-Hosted Uranium Deposits as a Possible Source for Critical Elements: The Eureka Mine Case, Castell-Estaó, Catalonia

Minerals ◽

10.3390/min10010034 ◽

2019 ◽

Vol 10 (1) ◽

pp. 34 ◽

Cited By ~ 1

Author(s):

Montgarri Castillo-Oliver ◽

Joan Carles Melgarejo ◽

Lisard Torró ◽

Cristina Villanova-de-Benavent ◽

Marc Campeny ◽

...

Keyword(s):

Organic Matter ◽

Low Temperature ◽

Black Shales ◽

Hydrothermal Fluids ◽

Uranium Deposits ◽

Critical Metals ◽

Fine Grained ◽

Critical Elements ◽

By Products ◽

Red Bed

The Eureka deposit in Castell-estaó in the Catalan Pyrenees is a Cu–U–V deposit, hosted by Triassic red-bed sandstones, and classified here as a low-temperature, sandstone-hosted stratabound metamorphite U deposit. The main mineralisation is stratabound, related to coal-bearing units and produced during the Alpine deformation by migration of hydrothermal fluids. In this stage, the original sedimentary and diagenetic components (quartz and calcite, micas, hematite and locally apatite) were replaced by a complex sequence of roscoelite, fine-grained REE phosphates, sulphides and Ni–Co arsenides and sulpharsenides, Ag–Pb selenides, bismuth phases, sulphosalts and uraninite. The black shales of the Silurian sediments underlying the deposit and the nearby Carboniferous volcanoclastic rocks are interpreted as the source of the redox-sensitive elements concentrated in Eureka. The sulphur source is related to leaching of the evaporitic Keuper facies. The REE transport would be facilitated by SO4-rich solutions. The reduction of these solutions by interaction with organic matter resulted in the widespread precipitation of REE and redox-sensitive elements, including many critical metals (V, Bi, Sb, Co), whereas barite precipitated in the oxidized domains. The occurrence of similar enrichments in critical elements can be expected in other similar large uranium deposits, which could be a source of these elements as by-products.

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