Minerals

39 pages, 3652 KiB

Open AccessFeature PaperReview

Coal and Coal By-Products as Unconventional Lithium Sources: A Review of Occurrence Modes and Hydrometallurgical Strategies for Metal Recovery

by Ewa Rudnik

Minerals 2024, 14(8), 849; https://doi.org/10.3390/min14080849 - 22 Aug 2024

Viewed by 490

Abstract

Lithium, a critical material for the global development of green energy sources, is anomalously enriched in some coal deposits and coal by-products to levels that may be considered economically viable. Recovering lithium from coal, particularly from coal gangue or coal ashes, offers a [...] Read more.

Lithium, a critical material for the global development of green energy sources, is anomalously enriched in some coal deposits and coal by-products to levels that may be considered economically viable. Recovering lithium from coal, particularly from coal gangue or coal ashes, offers a promising alternative for extracting this element. This process could potentially lead to economic gains and positive environmental impacts by more efficiently utilizing coal-based waste materials. This review focuses on lithium concentrations in coal and coal by-products, modes of lithium occurrence, methods used to identify lithium-enriched phases, and currently available hydrometallurgical recovery methods, correlated with pretreatment procedures that enable lithium release from inert aluminosilicate minerals. Leaching of raw coal appears inefficient, whereas coal gangue and fly ash are more feasible due to their simpler composition and higher lithium contents. Lithium extraction can achieve recovery rates of over 90%, but low lithium concentrations and high impurity levels in the leachates require advanced selective separation techniques. Bottom ash has not yet been evaluated for lithium recovery, despite its higher lithium content compared to feed coal. Full article

(This article belongs to the Special Issue Beneficiation and Extraction of Critical Metals from Ores and Secondary Resources)

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27 pages, 20829 KiB

Open AccessArticle

Elemental Geochemistry and Pb Isotopic Compositions of the Thick No. 7 Coal Seam in the Datun Mining Area, China

by Na Meng, Qianlong Xiao and Wu Li

Minerals 2024, 14(8), 848; https://doi.org/10.3390/min14080848 - 22 Aug 2024

Viewed by 317

Abstract

Thick coal seams recorded abundant petrological, geochemical, and mineralogical information regarding their formation, which in turn can reflect the characteristics of the coal-forming environments, provenance attributes, paleoclimate, and so on. In order to explore the geochemical and lead isotope characteristics of thick coal [...] Read more.

Thick coal seams recorded abundant petrological, geochemical, and mineralogical information regarding their formation, which in turn can reflect the characteristics of the coal-forming environments, provenance attributes, paleoclimate, and so on. In order to explore the geochemical and lead isotope characteristics of thick coal seams, the No. 7 coal seam in the Datun mining area, Jiangsu Province of China, was selected as the research object. In this work, 29 samples (including coal, roof, and floor rock samples) were collected from three coal mines in the Datun mining area. Through an analysis of the mineral composition and element geochemical characteristics in the coal samples, the enrichment degree of trace elements and modes of rare earth elements were determined. The genetic mechanism of abnormal enrichment of enriched elements is discussed, especially the modes of occurrence and isotope characteristics of Pb. The results showed the following: (1) The main minerals in the coal samples include quartz, potassium feldspar, plagioclase, calcite, dolomite, pyrite, gypsum, and clay minerals, with clay minerals, calcite, quartz, and dolomite being the most common. (2) The major element oxides in coal mainly include SiO₂, Al₂O₃, Fe₂O₃, MgO, CaO, Na₂O, K₂O, TiO₂, P₂O₅, and FeO. In the vertical direction, the variation of SiO₂, Al₂O₃, Fe₂O₃, MgO, K₂O, and FeO in coal samples from the three coal mines is consistent. The average value of Al₂O₃/TiO₂ in the samples of Kongzhuang, Longdong, and Yaoqiao coal mines is 28.09–50.52, which basically locates the samples in the felsic source area, such that the sediment source is considered to be felsic source rock. (3) Elements U, La, Pb, and other elements are more enriched in Kongzhuang coal mine samples; elements Th, U, La, Pb, and other elements are more enriched in the Longdong coal mine samples; and elements Th, U, La, Pb, and other elements are more enriched in the Yaoqiao coal mine samples. Furthermore, W is enriched in Yaoqiao mine samples and is highly enriched in Longdong mine samples. The mining area is generally rich in the elements U, La, and Pb. The distribution curves of rare earth elements in the three mines are inclined to the right, with negative Eu anomalies. The enrichment is of the light rare earth enrichment type. (4) Pb isotope data show that the samples from the three mines are mainly distributed in the orogenic belt and the subduction zone lead source areas, where the upper crust and the mantle are mixed, with individual sample points distributed in the mantle and upper crust lead source areas. Full article

(This article belongs to the Section Environmental Mineralogy and Biogeochemistry)

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25 pages, 8461 KiB

Open AccessReview

Regolith-Hosted Rare Earth Element Mineralization in the Esperance Region, Western Australia: Major Characteristics and Potential Controls

by Nikita Sergeev and Tiffany Collins

Minerals 2024, 14(8), 847; https://doi.org/10.3390/min14080847 - 22 Aug 2024

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Abstract

A number of regolith-hosted REE occurrences have recently been discovered in the Esperance region in southern Western Australia. This paper summarizes major characteristics of REE mineralization and discusses contributing factors and potential controls. The main aim is to explain why there is a [...] Read more.

A number of regolith-hosted REE occurrences have recently been discovered in the Esperance region in southern Western Australia. This paper summarizes major characteristics of REE mineralization and discusses contributing factors and potential controls. The main aim is to explain why there is a lack of highly sought-after ion-adsorption-clay-type REE deposits across the region despite the presence of the regolith-hosted REE mineralization on a regional scale. Local mineralization mostly occurs as continuous flat-lying enrichment “blankets” within the residual regolith developed over Archaean–Proterozoic granite gneisses and granitoids with elevated REE content. The enriched horizon is commonly located in the lower saprolite and saprock and is accompanied by an overlying REE-depleted zone. This distribution pattern, together with the data on HREE fractionation and the presence of the supergene REE minerals, indicates chemogenic type enrichment formed by supergene REE mobilization into groundwater, downward transport, and accumulation in the lower part of the weathering profile. Residual REE accumulation processes due to bulk rock volume and mass reduction during weathering also contribute to mineralization. It is proposed that climate and groundwater chemistry are the critical regional controls on the distribution of REEs in the weathering profile and on their speciation in the enrichment zone. Cenozoic aridification of climate in southwest Australia heavily overprinted pre-existing REE distributions in the weathering profile. Acidic (pH < 4), highly saline groundwaters intensely leached away any relatively weakly bound, adsorbed or colloidal REE forms, moving them downward. Dissolved REEs precipitated as secondary phosphates in neutral to alkaline environment at lower Eh near the base of the weathering profile forming the supergene enrichment zone. Low denudation rates, characteristic of areas of low relief under the arid climate, are favourable for the preservation of the existing weathering profiles with REE mineralization. Full article

(This article belongs to the Special Issue Chemical Weathering Studies)

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16 pages, 13977 KiB

Open AccessArticle

Cu–Polymetallic Deposit Exploration under Thick Cover in Gucheng–Yaxi Area Using Audio-Magnetotelluric and Spread-Spectrum-Induced Polarization

by Farid Ullah, Xin Zhou, Rujun Chen, Lunkai Yang, Hongchun Yao, Hao Hu, Siwen Chen and Quangong Wang

Minerals 2024, 14(8), 846; https://doi.org/10.3390/min14080846 - 22 Aug 2024

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Abstract

Successful geophysical exploration projects in the Gucheng–Yaxi area located in Gaochun District, Jiangsu Province, China, have been limited partly due to the complex geological conditions of the area and high artificial noise in data acquired using electrical and electromagnetic methods. In this study, [...] Read more.

Successful geophysical exploration projects in the Gucheng–Yaxi area located in Gaochun District, Jiangsu Province, China, have been limited partly due to the complex geological conditions of the area and high artificial noise in data acquired using electrical and electromagnetic methods. In this study, we deployed the new anti-interference spread-spectrum-induced polarization method (SSIP) and the audio-magnetotelluric (AMT) method to detect a copper–polymetallic deposit in the area. Two-dimensional inversion results in the Gucheng–Yaxi area revealed a high chargeability anomalous zone on the SSIP profile that coincided with a zone of moderate resistivity located between two resistor bodies on the AMT profile. A follow-up 1200 m drill hole was established at this high-chargeability, moderate-resistivity zone which encountered polymetallic (copper, lead, zinc, gold, and silver) mineralization at a depth of ≥400 m. Drill hole data analysis showed that mineralization occurred interspaced in the marble rock mass at varying depths. Furthermore, several low-resistivity, weak-chargeability sections were revealed and attributed to Cretaceous sediments and faults. These faults are thought to have played a critical role in the polymetallic mineralization genesis. In summary, this study demonstrated the successful of application of SSIP and AMT in detecting a metallic deposit in an area with high artificial noise. Hence, the geophysical prospection potential of the Gucheng–Yaxi area is great. Full article

(This article belongs to the Section Mineral Exploration Methods and Applications)

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15 pages, 5625 KiB

Open AccessArticle

Pan-African and Early Paleozoic Orogenic Events in Southern Tibet: Evidence from Geochronology and Geochemistry of the Kangbuzhenri Gneissic Granite in the Zhegu Area

by Ming Cheng, Xuming Hu, Yao Tang, Zhao Deng, Yingzi Min, Shiyi Chen, Saijun Sun and Huanzhan Zhou

Minerals 2024, 14(8), 845; https://doi.org/10.3390/min14080845 - 22 Aug 2024

Viewed by 304

Abstract

The Zhegu area in southern Tibet is situated in the central and eastern part of the Tethys Himalayan tectonic belt, with the Kangbuzhenri area being abundant in gneissic granites. This study examines the petrology, chronology, and geochemistry of the Kangbuzhenri gneissic granite, providing [...] Read more.

The Zhegu area in southern Tibet is situated in the central and eastern part of the Tethys Himalayan tectonic belt, with the Kangbuzhenri area being abundant in gneissic granites. This study examines the petrology, chronology, and geochemistry of the Kangbuzhenri gneissic granite, providing insights into its Pan-African and Early Paleozoic geological evolution. The zircon U-Pb chronology indicates an upper intercept age of ~539 Ma, reflecting Pan-African orogenic events in the eastern part of the Tethys Himalayan tectonic belt, and a lower intercept age of ~144 Ma, representing a late tectonic–thermal event. Geochemically, the gneissic granites are calc-alkaline peraluminous rocks with high SiO₂ and Al₂O₃ contents and low TiO₂, P₂O₅, MgO, and FeO^T contents. The gneissic granites are enriched in LREE and LILEs (Rb, Pb, Th, U, etc.), but relatively depleted in HREE and HFSEs (Nb, Ti, P, etc.). Most of them show a weak negative δEu anomaly, except for two samples which show a significant negative δEu anomaly due to the crystallization of plagioclase. Based on the above study, most of the gneissic granites exhibited the characteristics of an I-type granite, while two of the samples were a highly differentiated I-type granite with S-type affinities. All the above characteristics indicate that the gneissic granite likely originated from the partial melting of crustal materials and sediments with a minor involvement of mantle-derived materials. Combined with the previous chronological studies, the Kangbuzhenri gneissic granites were formed in an extensional tectonic environment during post-collision orogeny and then they were influenced by the Kerguelen mantle plume tectonic–thermal event around ~144 Ma and the subsequent Southern Tibet Detachment System (STDS). Full article

(This article belongs to the Section Mineral Geochemistry and Geochronology)

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18 pages, 5890 KiB

Open AccessArticle

An Approach to Accurately Identifying Binders in Historic Mortars by the Combination of Microscopic and Microanalytical Techniques

by Luís Almeida, António Santos Silva, Rosário Veiga and José Mirão

Minerals 2024, 14(8), 844; https://doi.org/10.3390/min14080844 - 21 Aug 2024

Viewed by 415

Abstract

Mortars are among the most important materials in building construction. They are generally obtained by mixing aggregates with an inorganic binder. The identification of mortar constituents, particularly the binder type in historic buildings, is one of the essential aspects of building conservation, considering [...] Read more.

Mortars are among the most important materials in building construction. They are generally obtained by mixing aggregates with an inorganic binder. The identification of mortar constituents, particularly the binder type in historic buildings, is one of the essential aspects of building conservation, considering that the new conservation materials must be chemically, mechanically, and physically compatible with the old masonries. Among other techniques used to characterise binders, those related to optical and electronic microscopy are particularly important. Microscopy and combined techniques may be the key to this identification since the classic mineralogical and chemical-based identification approaches are not conclusive enough in investigating the types of hydraulic binders in mortars. This work presents an analysis procedure to identify mortar binders by combining EDS microanalysis and petrography. Mortar samples of known composition were used as a reference for analyzing mortars from historic buildings. The proposed methodology made it possible to identify the type of binder or a mixture of binders based on the identification of the binder features by petrography together with analysis of the chemical composition of the paste by X-ray microanalysis under a scanning electron microscope. Full article

(This article belongs to the Special Issue Mineralogical and Geochemical Characterization of Geological Materials)

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37 pages, 33345 KiB

Open AccessArticle

LA-ICP-MS Analyses of Sulfides from Gold-Bearing Zones at the Perron Deposit, Abitibi Belt, Canada: Implications for Gold Remobilization through Metamorphism from Volcanogenic Mineralizations to Orogenic Quartz–Carbonate Veins

by Damien Gaboury, Dominique Genna, Jérôme Augustin, Maxime Bouchard and Jacques Trottier

Minerals 2024, 14(8), 843; https://doi.org/10.3390/min14080843 - 21 Aug 2024

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Abstract

The Perron deposit, located in the northern part of the Archean Abitibi belt, bears some of the highest gold-grade mineralization for orogenic-vein-type deposits worldwide (High-Grade Zone: HGZ). More than 13 gold-bearing zones with different sulfide assemblages, hydrothermal alterations, and gold grades have been [...] Read more.

The Perron deposit, located in the northern part of the Archean Abitibi belt, bears some of the highest gold-grade mineralization for orogenic-vein-type deposits worldwide (High-Grade Zone: HGZ). More than 13 gold-bearing zones with different sulfide assemblages, hydrothermal alterations, and gold grades have been recently outlined, and they range from volcanogenic to orogenic in origin. In addition, seven zones are hosted in a restricted volume of ~1 km³, which is called the Eastern Gold Zone. Pyrite, sphalerite, pyrrhotite, and chalcopyrite—each from a different gold-bearing zone—were analyzed with LA-ICP-MS to decipher their genetic links, mineralizing processes, and temperature of formation. The temperatures calculated with the sphalerite GGIMFis thermometer range from 348 to 398 °C. All gold-bearing zones recorded volcanogenic hydrothermal inputs at different intensities, manifested by pyrrhotite. Pyrite was late-metamorphic and related to the orogenic gold system induced by the contact metamorphism of amphibolite facies. The pyrrhotite grains had very homogeneous trace element signatures in all zones, which is a characteristic of metamorphic recrystallization, exhibiting a loss of mobile elements (Au, Te, Bi, Tl, Sn, W, In) but high concentrations of Ni, Co, and As. Conversely, the pyrite was systematically enriched with all elements depleted from pyrrhotite, bearing five specific signatures of element enrichments: W, Tl, Sn, In-Cd-Zn, and Bi-Te-Au. For gold-rich zones (e.g., the HGZ), gold was linked to the Bi-Te-Au signature of pyrite, with Bi enrichment occurring at up to 72,000 times the background level in Archean shale pyrite. It was concluded that gold was transported, at least in part, as Bi-Te melts in the previously documented non-aqueous orogenic fluids, hence accounting for the very-high-grade gold content of the HGZ. Genetically, the metamorphism of primary gold-bearing volcanogenic mineralizations was the main source of gold during the overprinting of amphibolite (600 °C) in a metamorphically induced orogenic mineralizing event. A strong volcanogenic pre-enrichment is considered the main factor accounting for the gold endowment of the Eastern Gold Zone. Full article

(This article belongs to the Special Issue Understanding Hydrothermal Ore Deposits)

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16 pages, 2871 KiB

Open AccessReview

Application of Nanofibrous Clay Minerals in Water-Based Drilling Fluids: Principles, Methods, and Challenges

by Guanzheng Zhuang, Jiajun Zhang, Jinrong Chen, Qian Liu, Wenxiao Fan and Qiang Li

Minerals 2024, 14(8), 842; https://doi.org/10.3390/min14080842 - 21 Aug 2024

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Abstract

Nanofibrous clay minerals, specifically palygorskite (Pal) and sepiolite (Sep), have been becoming a new generation of rheological additives for drilling fluid systems due to their unique nanostructure, high performance, environmentally benign nature, and cost-effectiveness. These nanoclay minerals exhibit excellent colloidal and rheological properties [...] Read more.

Nanofibrous clay minerals, specifically palygorskite (Pal) and sepiolite (Sep), have been becoming a new generation of rheological additives for drilling fluid systems due to their unique nanostructure, high performance, environmentally benign nature, and cost-effectiveness. These nanoclay minerals exhibit excellent colloidal and rheological properties in aqueous systems, even in saline and high-temperature environments. Although Pal and Sep have been employed as auxiliary rheological additives in a few cases to enhance the salt resistance of conventional water-based drilling fluids (WBDFs), these two clay minerals have not yet been used on a large scale due to a lack of understanding of their structures and properties, as well as the control of their performance. This paper presents a comprehensive review of the clay mineralogy, colloidal chemistry, rheological behaviors, and filtration properties of nanofibrous clay minerals in WBDFs, with critical comments. It also discusses the challenges and prospects for further research. This review provides new insights into fundamental and applied studies of nanofibrous clay minerals and helps promote the large-scale application of nanofibrous clay products in drilling fluids. Full article

(This article belongs to the Special Issue Clay Minerals: Roles in Oil and Gas Generation, Drilling, and Enhanced Recovery)

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29 pages, 30448 KiB

Open AccessArticle

The Ore-Forming Process of Washan Porphyrite Iron Deposits in the Ningwu District Associated with Iron Oxide Apatite (IOA) Deposits and Iron Oxide Copper Gold (IOCG) Deposits

by Zhen Liu, Wei Xu, Chunming Liu and Dezhi Huang

Minerals 2024, 14(8), 841; https://doi.org/10.3390/min14080841 - 21 Aug 2024

Viewed by 364

Abstract

The Washan iron deposits in Ningwu district contain different magma-related genetic natures, including magmatic, magmatic–hydrothermal and hydrothermal types, and their ore-forming processes remain a subject of debate. To elucidate the ore-forming processes of iron ores from Washan, we present textural, major element analytical, [...] Read more.

The Washan iron deposits in Ningwu district contain different magma-related genetic natures, including magmatic, magmatic–hydrothermal and hydrothermal types, and their ore-forming processes remain a subject of debate. To elucidate the ore-forming processes of iron ores from Washan, we present textural, major element analytical, and thermal data of magnetites from various ore bodies in Washan, probing the crystallization conditions and subsequent formation sequence of magnetites. SEM analysis with back-scattered electron (BSE) imaging reveals diverse magnetite textures, including mineral inclusions, exsolution lamellae, and recrystallization features, reflecting the transitional environment from magmatic to hydrothermal. Based on Ti, V, and Cr compositions of magnetite from different ore bodies, two distinct evolution trends of genetic processes are identified, including evolution paths from porphyry-type to IOA- and IOCG-type magnetite. High-resolution WDS mapping highlights the intensifying alterations during this process. Calculated magnetite crystallization temperatures among different types of magnetite range from 597 °C to 378 °C, suggesting a cooling trend from porphyry-type magnetite (~558 °C) to IOA-type magnetite (~515–439 °C) and IOCG-type magnetite (~378 °C). These results underscore the significant role of magma-derived hydrosaline liquids and vapors in the formation of iron ores from Washan, where variations in the salinity of ore-forming fluids lead to different evolutionary paths for subsequent generations of magnetite. The metallogenic model of the Washan iron deposit suggests that highly saline, iron-rich fluids connect the varying geneses of magnetite, transitioning from deeply formed porphyry-type magnetite to IOA- or IOCG-type magnetite generated in the subaerial zone. Full article

(This article belongs to the Section Mineral Deposits)

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15 pages, 3441 KiB

Open AccessArticle

Analysis of the Effect of Surfactants on the Performance of Apatite Column Flotation

by Thessa F. Mendes, Angelica S. Reis, André C. Silva and Marcos A. S. Barrozo

Minerals 2024, 14(8), 840; https://doi.org/10.3390/min14080840 - 20 Aug 2024

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Abstract

Given that particle and bubble size, as well as their surface properties, are pivotal in froth flotation, surfactants have been extensively employed due to their impact on bubble size and froth stabilization. This study aimed to investigate the influence of surfactants on the [...] Read more.

Given that particle and bubble size, as well as their surface properties, are pivotal in froth flotation, surfactants have been extensively employed due to their impact on bubble size and froth stabilization. This study aimed to investigate the influence of surfactants on the performance of apatite flotation in column. Three different categories of surfactants were examined: anionic, amphoteric, and nonionic, specifically Lupromin, Genagen, and Triton X-100, respectively. The critical coalescence concentration (CCC) and surface tension of each surfactant were determined. The impact of these surfactants on reducing bubble size was quantified, and their subsequent effects on apatite flotation in a column were assessed. The most favorable flotation response for Genagen was achieved at CCC and pH 11, resulting in the highest apatite recovery and the smallest bubble size. For Triton X-100, the best condition was attained at ¼ CCC and pH 11. However, overall, Lupromin was the surfactant that yielded the best flotation results (at ¼ CCC and pH 11). The superior performance of this anionic surfactant was corroborated by chemical adsorption results, as demonstrated by FTIR analyses. Full article

(This article belongs to the Special Issue Surface Chemistry and Reagents in Flotation)

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18 pages, 2454 KiB

Open AccessArticle

Mantle Volatiles and Heat Contributions to the Cu-Pb-Zn Mineralization in the Baoshan Deposit, South China: Constraints from He and Ar Isotopes

by Jinchuan Huang, Jiantang Peng and Tengxiang Xie

Minerals 2024, 14(8), 839; https://doi.org/10.3390/min14080839 - 19 Aug 2024

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Abstract

The Baoshan deposit is one of the important Cu-Pb-Zn deposits associated with granitic rocks in the Nanling Range, South China. Here, we present He and Ar isotope data for the Baoshan deposit to decipher the contributions of mantle-derived volatiles and heat to its [...] Read more.

The Baoshan deposit is one of the important Cu-Pb-Zn deposits associated with granitic rocks in the Nanling Range, South China. Here, we present He and Ar isotope data for the Baoshan deposit to decipher the contributions of mantle-derived volatiles and heat to its Cu-Pb-Zn mineralization. The ore-forming fluids in sphalerite and pyrite exhibited ³He/⁴He ratios up to 1.51 Ra. A linear correlation between He and Ar isotopes suggests that the ore-forming fluids were a mixture of a predominantly mantle-derived fluid with a high ³He/⁴He ratio and a shallow crustal fluid, characterized by a low ³He/⁴He ratio. The δ³⁴S values of sulfides in the Baoshan deposit ranged from +2.30 to +5.21‰, consistent with the magma-derived sulfur. The calculated ³He/Q ratios for the ore-forming fluid exceeded those of mid-oceanic ridge hydrothermal solutions by 10 to 50 times, indicating that the ore-forming fluids acquired both heat and volatiles in a convective hydrothermal regime rather than a conductive one. Therefore, there is a significant contribution of mantle-derived volatiles, heat, and possibly metals, to the Cu-Pb-Zn mineralization in the Baoshan deposit, and the continuous influx of mantle-derived fluids/melts probably plays a crucial role during the Cu-Pb-Zn mineralization related to granitic rocks. Full article

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21 pages, 12899 KiB

Open AccessArticle

Location Prediction Study of Fluorite Ore in Shallow Cover Area: Evidence from Integrated Geophysical Surveys

by Liu Cheng, Li Han, Yang Kai, Gao Yongbao, Tang Weidong and Yao Chuan

Minerals 2024, 14(8), 838; https://doi.org/10.3390/min14080838 - 19 Aug 2024

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Abstract

The Beishan region is a vital fluorite metallogenic belt in northwest China, characterized by favorable geological conditions for fluorite mineralization. However, being located in the Gobi Desert and affected by shallow cover layers, only a few outcrops can be observed on the surface. [...] Read more.

The Beishan region is a vital fluorite metallogenic belt in northwest China, characterized by favorable geological conditions for fluorite mineralization. However, being located in the Gobi Desert and affected by shallow cover layers, only a few outcrops can be observed on the surface. Therefore, comprehensive geophysical research is necessary to locate and predict regional metallogenic potential and the spatial distribution of veins beneath the cover. This study conducted a combination of ground magnetic method (GM), induced polarization (IP) surveys, portable gamma-ray (PGR), portable X-ray fluorescence analyses (PXRF), and audio Magnetotelluric (AMT) to conduct comprehensive exploration. The IP and GM effectively identified concealed ore-bearing space distributions and ground PGR- and PXRF-constrained mineralization anomalies, while AMT surveys constructed deep electrical structure models for ore deposits. This approach delineated concealed fluorite deposit locations as well as potential magmatic–hydrothermal migration pathways. Engineering verification confirmed the effectiveness of this method combination. This study established a comprehensive geological–geophysical positioning prediction technique that can serve as a reference for locating and predicting fluorite deposits in shallow-covered areas within the Gobi Desert. Full article

(This article belongs to the Special Issue Advances in Magnetic and Electromagnetic Techniques for Mineral Exploration: Enhancing Resource Discovery)

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14 pages, 5127 KiB

Open AccessArticle

Deep Geological Structure Analysis of the Dongyang Area, Fujian, China: Insights from Integrated Gravity and Magnetic Data

by Zhenyu Zhang, Yongbo Li, Liang Chen, Qiang Zhang and Yue Sun

Minerals 2024, 14(8), 837; https://doi.org/10.3390/min14080837 - 19 Aug 2024

Viewed by 299

Abstract

To explore the deep geological structure of the Dongyang area in Fujian, China, gravity data from the area and its surroundings were collected and processed. Additionally, a high-precision magnetic survey was conducted in the Zhongxian region of this area, with subsequent analysis of [...] Read more.

To explore the deep geological structure of the Dongyang area in Fujian, China, gravity data from the area and its surroundings were collected and processed. Additionally, a high-precision magnetic survey was conducted in the Zhongxian region of this area, with subsequent analysis of the magnetic anomalies. Through the integration of regional geological data, a comprehensive analysis was carried out on the characteristics of gravity–magnetic anomalies and deep geological structures in the Dongyang area. The study indicates that the primary portion of the Dongyang area lies southwest of the expansive circular volcanic structure spanning Dehua to Yongtai. Two significant residual gravity anomalies were identified within the region, interpreted as the Xiaoban-Shuangqishan and Dongyang-Lingtouping residual gravity-positive anomalies. In the Zhongxian region, the magnetic field exhibits complexity with notable amplitude variations. Positive anomalies predominate in the western and northern sectors, while localized positive anomalies are prominent in the eastern region. The central area portrays a circular and disordered mix of positive and negative anomalies. Particularly distinctive are the band-shaped and fan-shaped negative anomalies curving from northeast to southeast through the central region. Various positive and negative anomalies of varying strengths, gradients, and orientations overlay both positive and negative magnetic backgrounds in specific locales. Moreover, the Dongyang area showcases well-developed fault structures, primarily oriented in northeast and northwest directions. Leveraging the regional magnetic attributes in conjunction with regional geological data, 39 faults were deduced in the Zhongxian region of the Dongyang area, delineating three promising mineralization zones. Full article

(This article belongs to the Special Issue Advances in Magnetic and Electromagnetic Techniques for Mineral Exploration: Enhancing Resource Discovery)

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23 pages, 14189 KiB

Open AccessArticle

The Differences in the Li Enrichment Mechanism between the No. 6 Li-Rich Coals and Parting in Haerwusu Mine, Ordos Basin: Evidenced Using In Situ Li Microscale Characteristics and Li Isotopes

by Guohong Qin, Jinhao Wei, Yingchun Wei, Daiyong Cao, Xin Li and Yun Zhang

Minerals 2024, 14(8), 836; https://doi.org/10.3390/min14080836 - 18 Aug 2024

Viewed by 438

Abstract

As a potential strategic mineral resource, lithium (Li) in coal measures (including coal and parting) has attracted increasing attention from scholars globally. For a long time, Li in coal measures has been studied mainly on the macro-scale (whole rock); however, the microscopic characteristics [...] Read more.

As a potential strategic mineral resource, lithium (Li) in coal measures (including coal and parting) has attracted increasing attention from scholars globally. For a long time, Li in coal measures has been studied mainly on the macro-scale (whole rock); however, the microscopic characteristics of Li and Li isotope variations in coal measures are less well known. In this study, the No. 6 coal measures in the Haerwusu Mine were studied using ICP-MS, XRD, SEM-EDS, MC-ICP-MS, and LA-ICP-MS. The geochemical and mineralogical characteristics, the microscale distribution of Li in minerals, and the Li isotopes of Li-rich coal and parting in the No. 6 coal measure were investigated. The results show that the Li content in the No. 6 coal seam ranges from 3.8 to 190 μg/g (average 83 μg/g), which is lower than the parting (290 μg/g) and higher than the comprehensive evaluation index of Li in Chinese coal (80 μg/g). LA-ICP-MS imaging showed that Li in the coal is mainly contained within cryptocrystalline or amorphous lamellae aluminosilicate materials, and the Li content in lenticular aggregate kaolinite is low. The Li in parting is mainly found in illite/chlorite. The δ⁷Li of the coals was 3.86‰, which may be influenced by the input of the source rock. The δ⁷Li of the parting (7.86‰), which was higher than that of the coal, in addition to being inherited from the source rock, was also attributed to the preferential adsorption of ⁷Li by the secondary clay minerals entrapped in the parting from water during diagenetic compaction. Finally, by integrating the peat bog sediment source composition, sedimentary environment evolution, and Li isotope fractionation mechanism of No. 6 coal, a Li metallogenic model in the Li-rich coal measure was initially established. In theory, the research results should enrich the overall understanding of the Li mineralization mechanism in coal measures from the micro-scale in situ and provide a scientific basis for the comprehensive utilization of coal measure resources. Full article

(This article belongs to the Special Issue Mineralization Mechanism and Geochemical Characteristics of Coals and Associated Minerals)

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20 pages, 7605 KiB

Open AccessArticle

Geochronology and Geochemistry of the Uhelchulu Quartz Diorite-Granodiorite in Inner Mongolia of China: Implications for Evolution of the Hegenshan Ocean in the Early-Middle Devonian

by Tianshe Cheng, Wenjing Yang, Chao Teng, Xinjie Yang and Deng Xiao

Minerals 2024, 14(8), 835; https://doi.org/10.3390/min14080835 - 17 Aug 2024

Viewed by 592

Abstract

The Uhelchulu quartz diorite-granodiorite intrusions in Xiwuqi, Inner Mongolia, are exposed along the northwestern margin of the Xilinhot microcontinental block, located within the central and eastern parts of the southeastern Hegenshan suture zone. LA-ICP-MS zircon U-Pb dating yielded crystallization ages of (396 ± [...] Read more.

The Uhelchulu quartz diorite-granodiorite intrusions in Xiwuqi, Inner Mongolia, are exposed along the northwestern margin of the Xilinhot microcontinental block, located within the central and eastern parts of the southeastern Hegenshan suture zone. LA-ICP-MS zircon U-Pb dating yielded crystallization ages of (396 ± 8) Ma for the quartz diorite and (385 ± 5) Ma for the granodiorite, indicating an Early-Middle Devonian magmatic event. The quartz diorite exhibits I-type granite features, characterized by elevated Al₂O₃ (14.33–15.43 wt%), MgO (3.73–5.62 wt%), and Na (Na₂O/K₂O = 1.04–1.44), coupled with low P₂O₅ (0.15–0.20 wt%) and TiO₂ (0.73–0.99 wt%). Trace element patterns show relative enrichments in Rb, Th, U, and Pb, while Nb, Ta, Sr and Ti are relatively depleted. Total REE contents are relatively low (123–178 ppm), with significant LREE enrichment (ΣLREE/ΣHREE = 4.75–5.20), and a non-obvious Eu anomaly (δEu = 0.75–0.84). In contrast, the granodiorite displays S-type granite characteristics, with high SiO₂ (70.48–73.01 wt%), K (K₂O/Na₂O = 1.35–1.83), Al₂O₃ (A/CNK = 1.16–1.31), and a high differentiation index (DI = 76–82). Notably, MgO (1.44–2.24 wt%) contents are low, and significant depletions of Ba, Sr, Ti, and Eu are observed, while Rb, Pb, Th, U, Zr, and Hf are significantly enriched. Total REE contents are relatively low (178–314 ppm), exhibiting significant LREE enrichment (LREE/HREE = 6.17–8.36) and a pronounced negative Eu anomaly (δEu = 0.34–0.49). The overall characteristics point towards an active continental margin arc background for the Uhelchulu intrusions. Previous studies have suggested that the Hegenshan ocean continuously subducted northward from the Early Carboniferous to the Late Permian, but there is a lack of evidence for its geological evolution during the pre-Early Carboniferous. Therefore, this paper provides a certain basis for studying the geological evolution during the pre-Early Carboniferous in the Hegenshan ocean. We preliminarily believed that the Hegenshan ocean underwent a southward subduction towards the Xilinhot microcontinental block in the Xiwuqi area, at least from the Early Devonian to the Middle Devonian and the Hegenshan ocean may might have undergone a shift in subduction mechanism during the Late Devonian or Early Carboniferous. Full article

(This article belongs to the Section Mineral Geochemistry and Geochronology)

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20 pages, 5613 KiB

Open AccessArticle

Alteration and Non-Formula Elements Uptake of Zircon from Um Ara Granite, South Eastern Desert, Egypt

by Hamdy H. Abd El-Naby

Minerals 2024, 14(8), 834; https://doi.org/10.3390/min14080834 - 17 Aug 2024

Viewed by 348

Abstract

The Um Ara granites are a suite of granitoid rocks located in the southern part of the Eastern Desert of Egypt. The integration of various electron probe micro analyzer (EPMA) techniques, such as backscattered electron (BSE) imaging, X-ray compositional mapping, and wavelength dispersive [...] Read more.

The Um Ara granites are a suite of granitoid rocks located in the southern part of the Eastern Desert of Egypt. The integration of various electron probe micro analyzer (EPMA) techniques, such as backscattered electron (BSE) imaging, X-ray compositional mapping, and wavelength dispersive spectrometry (WDS), has provided valuable insights into the alteration process of zircon in the Um Ara granite. The zircon exhibits high concentrations of non-formula elements such as P, Al, Ca, Fe, Ti, and REEs, suggesting that the alteration involved coupled dissolution-reprecipitation processes influenced by aqueous fluids. The negative correlations between Zr and the non-formula elements indicate that these elements were incorporated into zircon at the expense of Zr and Si, significantly affecting the distribution and fractionation of REEs in the original zircon. Based on the presented data and literature knowledge, the sequence of alteration events is proposed as follows: (1) initial zircon crystallization around 603 Ma accompanied by the formation of other U- and Th-bearing minerals like xenotime, thorite, monazite, and apatite; (2) long-term metamictization leading to fractures and cracks that facilitated fluid circulation and chemical changes; (3) a major hydrothermal event around 20 Ma that released a suite of non-formula elements from the metamicted zircon and associated minerals, with the enriched hydrothermal fluids subsequently incorporating these elements into the modified zircon structure; and (4) further low-temperature alteration during subsequent pluvial periods (around 50,000–159,000 years ago), facilitated by the shear zones in the Um Ara granites, may have allowed further uptake of non-formula elements. The interplay between hydrothermal fluids, meteoric water, and the shear zone environments appears to have been a key driver for the uptake of non-formula elements into the altered zircon. Full article

(This article belongs to the Section Mineral Geochemistry and Geochronology)

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18 pages, 29127 KiB

Open AccessArticle

Multi-Scale Characterization of Pores and Fractures in Coals with Different Coal-Body Structures from the Jincheng Mine, Qinshui Basin, Northern China

by Haoran Yang, Xiaomei Wang, Rui Li, Pancun Chai, Fan Deng and Xingxing Guo

Minerals 2024, 14(8), 833; https://doi.org/10.3390/min14080833 - 17 Aug 2024

Cited by 1 | Viewed by 396

Abstract

The Qinshui Basin is located in the southeast of Shanxi Province, China. It is one of the most abundant coal resources from Permo-Carboniferous North China. It is rich in coal and coalbed methane resources. However, the accumulation of coalbed methane is complex and [...] Read more.

The Qinshui Basin is located in the southeast of Shanxi Province, China. It is one of the most abundant coal resources from Permo-Carboniferous North China. It is rich in coal and coalbed methane resources. However, the accumulation of coalbed methane is complex and the enrichment law has not been fully understood because of the high heterogeneity of coal reservoirs in the Qinshui Basin. The examination of dissimilarities between tectonically deformed coals (TDCs) and primary coals at multiple scales holds paramount importance in advancing our understanding of the occurrence and flow patterns of coalbed methane, and in providing guidance for exploration efforts. In the present study, the samples from the Jincheng Mine, Qinshui Basin, were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP), CO₂ gas adsorption and 3D X-ray micro-computed tomography. The results showed that the dominant minerals in coal were illite, kaolinite, and calcite, with minor amounts of quartz and ankerite. In comparison to primary coal, tectonism could increase the microfractures density of type A (the fracture of width ≥ 5 μm and length > 10 mm) in TDCs. In CO₂ gas adsorption in mylonite coal, it was observed that the volume of micropores (<2 nm) was significantly reduced leading to a decrease in gas adsorption capacity. The result of Micro-CT scanning revealed that the minerals occurred as veins in primary coal, but as irregular aggregates in TDCs. Moreover, tectonism had a staged impact on fracture structure, which was initially closed in cataclastic coal and then formed into granulated coal during the tectonic evolution. The effects of tectonism on coal structure had an impact on the connectivity of micropores at the micrometer scale by the destruction of the pore throat structure, increasing the heterogeneity of the reservoir. These findings help to better understand the changes in TDC structure at different scales for developing effective strategies for coalbed methane exploration and production. Full article

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38 pages, 22170 KiB

Open AccessArticle

New Geochemical and Geochronological Constraints on the Genesis of the Imourkhssen Cu±Mo±Au±Ag Porphyry Deposit (Ouzellagh-Siroua Salient, Anti-Atlas, Morocco): Geodynamic and Metallogenic Implications

by Mariam Ferraq, Saïd Belkacim, Li-Zhen Cheng, Joshua H. F. L. Davies, Morgann G. Perrot, Abdelhay Ben-Tami and Mohammed Bouabdellah

Minerals 2024, 14(8), 832; https://doi.org/10.3390/min14080832 - 16 Aug 2024

Viewed by 523

Abstract

The Imourkhssen porphyry Cu±Mo±Au±Ag deposit is located at the Ouzellagh-Siroua Salient (OSS) straddling the boundary between the central Anti-Atlas and the central High Atlas. It is characterized by a typical porphyry-style mineralization. The volcanic rocks are intruded by numerous magmatic rocks of the [...] Read more.

The Imourkhssen porphyry Cu±Mo±Au±Ag deposit is located at the Ouzellagh-Siroua Salient (OSS) straddling the boundary between the central Anti-Atlas and the central High Atlas. It is characterized by a typical porphyry-style mineralization. The volcanic rocks are intruded by numerous magmatic rocks of the Ouarzazate Group (580–539 Ma), referred to as the Late Ediacaran magmatic suites (LEMS). Of these, the Askaoun, Imourkhssen, and Imourgane granites are the most significant as they are related to the porphyry mineralization. The entire set is intruded by the Zaghar mafic dyke swarms. Zircon U-Pb dating of the Imourkhssen granite and the ore-bearing granite porphyry shows that these intrusive rocks were emplaced at 558 ± 1 and 550 ± 2 Ma, respectively. Moreover, the whole-rock major and trace element geochemistry reveal a high-K calc-alkaline I-type composition, consistent with an emplacement in a post-collisional setting under a trans-tensional tectonic regime. Ore bodies are hosted by the Askaoun granodiorite as well as the Imourgane granite. The mineralization occurs as fine-grained dissemination and infills of hydrothermally altered NNE–SSW to N–S trending veins and veinlets. Ore-related hydrothermal alteration consists of potassic, chlorite-sericite, serecitic, and propylitic mineral assemblages along with pervasive silicification and pyritization, providing a porphyry-style alteration pattern. The ore periods comprise supergene and magmatic-hydrothermal periods. The latter includes primary dissemination and secondary NNE–SSW to N–S ore-bearing system stages. The occurrence of molybdenite is either restricted to the potassic and chlorite-sericite alteration zones of the ore-bearing granite as fine disseminations or alternatively as veinlet infills within the propylitic halos. The molybdenite occurrences along with pyrite, chalcopyrite, galena, and tennantite dissemination are assigned to the primary ore stage, while the NNE–SSW to N–S ore-bearing system is related to the secondary ore stage. It consists of pyrite, chalcopyrite, bornite, covellite, diagenite, sphalerite, hematite, galena, gold, and chenguodaite. The predominance of cockade and crack-and-seal textures suggest multiple episodes of ore-forming fluid circulations under epithermal conditions. The supergene stage is achieved by subordinate malachite, azurite, barite, hematite, epsomite, and chrysocolla. From the descriptions above, we argue that the Imourkhssen Cu±Mo±Au±Ag mineralization shares many mineralogical and paragenetic attributes of porphyry-copper deposits. Full article

(This article belongs to the Special Issue Igneous Rocks and Related Mineral Deposits)

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17 pages, 4298 KiB

Open AccessArticle

Effect of Solid Ratio and Particle Size on Dissolution of Heat-Activated Lizardite at Elevated Pressures and Moderate Temperatures

by Ammar Abu Fara, Mark R. Rayson, Geoff F. Brent, Timothy K. Oliver, Michael Stockenhuber and Eric M. Kennedy

Minerals 2024, 14(8), 831; https://doi.org/10.3390/min14080831 - 16 Aug 2024

Viewed by 321

Abstract

This study investigates the effect of the particle size and solid-to-liquid ratio on the dissolution rate of magnesium (Mg) and silicon (Si) in heat-activated lizardite. The investigation was conducted under specific conditions: without the presence of sodium bicarbonate (NaHCO₃), at a [...] Read more.

This study investigates the effect of the particle size and solid-to-liquid ratio on the dissolution rate of magnesium (Mg) and silicon (Si) in heat-activated lizardite. The investigation was conducted under specific conditions: without the presence of sodium bicarbonate (NaHCO₃), at a moderate temperature (40 °C), and under elevated CO₂ pressure (100 bar). The aim was to isolate the dissolution reactions and enhance comprehension of the factors constraining the overall yields in the Albany Research Center (ARC) mineral carbonation process. Our study disclosed two distinct dissolution regimes: an initial stage with a rapid initial rate of Mg extraction, resulting in the fraction of Mg extracted ranging from 30 to 65% during the first 20 min of the experiment, following which the dissolution rate decreases dramatically. The initial rapid dissolution stage is primarily driven by the low pH of the supernatant solution, resulting from CO₂ dissolution, leading to a higher concentration of protons that extract Mg²⁺ cations. However, as the heat-activated lizardite dissolution progresses, the pH increases due to the high level of leached Mg²⁺, and a diffusion barrier forms due to the precipitation of amorphous silica. This phenomenon ultimately slows down the mineral’s dissolution rate during the latter stages of particle dissolution. Full article

(This article belongs to the Special Issue Mineralogy, Chemistry, Weathering and Application of Serpentinite)

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18 pages, 7588 KiB

Open AccessArticle

Estimation of the Potential Antimony Resource in Southern China with the Geochemical Block Method

by Yude Du, Zhixuan Han, Bimin Zhang, Zhengnan Dong, Xiaocheng Wei, Haonan Zhao, Xiaolong Wang, Man Zhang and Hanliang Liu

Minerals 2024, 14(8), 830; https://doi.org/10.3390/min14080830 - 16 Aug 2024

Viewed by 366

Abstract

Antimony (Sb) is widely utilized in modern industries and classified as a critical mineral worldwide. China possesses the most abundant Sb mineral resources globally, with over 70% of proven reserves concentrated in southern China. However, due to excessive exploitation, the lifespan of Sb [...] Read more.

Antimony (Sb) is widely utilized in modern industries and classified as a critical mineral worldwide. China possesses the most abundant Sb mineral resources globally, with over 70% of proven reserves concentrated in southern China. However, due to excessive exploitation, the lifespan of Sb reserves is less than ten years. Therefore, the knowledge of Sb needs to be urgently strengthened. Here, the effectiveness of the geochemical block method to delineate the prospective areas of Sb deposits and determine the potential resource of Sb was studied, with geochemical data covering 2.3 million km² across southern China. The statistical results showed that the median concentration of Sb in stream sediments (1.05 ppm) in southern China was 1.5 times that of whole China, indicating a significantly elevated background level of Sb in southern China. By setting the threshold value at 2.98 ppm, a total of nine distinct geochemical blocks were delineated. Remarkably, 85% and 76% of the large and medium Sb deposits were located within these geochemical blocks, respectively. Taking the block containing the Xikuangshan giant Sb deposit in Hunan Province as the model, the metallogenic coefficient of Sb is calculated to be 0.32%. The total potential Sb resources in southern China within a depth of 1000 m are estimated to be 21.939 million tons, which are primarily concentrated in the provinces of Hunan, Guangxi, Yunnan, and Guizhou. When the threshold value is set at 4.19 ppm, the predicted potential resources of Sb are 21.45 million tons in twelve blocks, which closely approximate 21.939 million tons. The estimated Sb resource in this study significantly surpasses the proven reserves. The periphery and deep areas of known Sb deposits still hold promising prospects for exploration. This study highlighted the effectiveness of employing the geochemical block method to estimate the potential resources of Sb and determined the ore-prospecting direction of Sb deposits. However, it is important to acknowledge and address the overestimation of predicted resources resulting from the high geological background. Full article

(This article belongs to the Section Mineral Exploration Methods and Applications)

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20 pages, 30900 KiB

Open AccessArticle

Effects of Low-Temperature Heat Treatment on Mong Hsu Rubies

by Chen Fan and Yung-Chin Ding

Minerals 2024, 14(8), 829; https://doi.org/10.3390/min14080829 - 15 Aug 2024

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Abstract

This study examined the effects of low-temperature heat treatment on the characteristics of the rubies from Mong Hsu, Myanmar. Five ruby samples were heated to 400, 600, 900 and 1200 °C for different durations, respectively. Before and after each heating step, a visual [...] Read more.

This study examined the effects of low-temperature heat treatment on the characteristics of the rubies from Mong Hsu, Myanmar. Five ruby samples were heated to 400, 600, 900 and 1200 °C for different durations, respectively. Before and after each heating step, a visual examination was conducted with a gem microscope under different illumination conditions. Various spectral analyses such as UV-Vis, FTIR, Raman and PL were also used to examine the effect of heating on the ruby samples. The low-temperature heat treatment enhanced the ruby samples by causing the dark blue core to partially or completely fade away. It then increased the overall light transmittance and enhanced the fluorescence peak around 694 nm but did not improve the red hue of the samples. Two major changes were found in the experiments. One was the dark blue core of the samples that faded as the heating temperature increased. They were verified by the spectra to be the variation in the intervalence charge transfer between Fe²⁺ and Ti⁴⁺. The variation in the intervalence charge transfer of Mong Hsu ruby was not noticeable before heating to 900 °C but changed dramatically when heated to 1200 °C. The other was the shift of the FTIR peak, which is caused by decomposition of minerals due to heating. An FTIR 630 cm⁻¹ peak proved to be sensitive to the low-temperature heating and might be helpful for detecting low-temperature treatment. Full article

(This article belongs to the Special Issue Gem Deposits: Mineralogical and Gemological Aspects, 2nd Edition)

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23 pages, 6255 KiB

Open AccessReview

A Critical Review on the Flotation Reagents for Phosphate Ore Beneficiation

by Liangmou Yu, Pan Yu and Shaojun Bai

Minerals 2024, 14(8), 828; https://doi.org/10.3390/min14080828 - 15 Aug 2024

Viewed by 427

Abstract

Phosphate ore is the dominating natural resource for the production of fertilizers and phosphorous chemical products. Flotation is the most widely employed technique to enrich apatite and remove the impurities for the separation of the phosphate ore. The flotation reagents play an important [...] Read more.

Phosphate ore is the dominating natural resource for the production of fertilizers and phosphorous chemical products. Flotation is the most widely employed technique to enrich apatite and remove the impurities for the separation of the phosphate ore. The flotation reagents play an important role in this efficient separation of phosphate ores. In the last few decades, great progress has been achieved in the flotation reagents for phosphate ores. However, a critical review on this theme has rarely been reported in recent years. Thus, the goal of this paper is to critically analyze the published literature on the flotation reagents for phosphate ores, mainly ranging from 2010 to 2024, including the regulators, depressors, collectors, and frothers. Additionally, the interaction mechanisms between the reagents and mineral surfaces were analyzed. It is concluded that sulfuric acids and its derivatives play a leading role in the depression of phosphate minerals. Highly selective biobased depressants have become potential carbonate inhibitors. Additionally, the derivatization and synthesis of multi-functional compounds and identifying the biobased frothers are the main development trends of collectors and frothers. Overall, a high-quality concentrate with a 31.05% grade and 98.21% recovery at pH 5 was achieved using lecithin as an ecofriendly amphoteric collector and sulfuric acid as the depressor when the feed contained 24.49% P₂O_5, which was superior to other flotation indexes of similar phosphate ores. This review will help researchers to document knowledge gaps and provide a reference for the efficient and green beneficiation of phosphate ores in the future. Full article

(This article belongs to the Section Mineral Processing and Extractive Metallurgy)

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15 pages, 5434 KiB

Open AccessArticle

Evaluating the Behavior of Bauxite Tailings Dewatering in Decanter Centrifuges

by Camila Botarro Moura, Arthur Pinto Chaves, Rafael Alves de Souza Felipe and Homero Delboni Júnior

Minerals 2024, 14(8), 827; https://doi.org/10.3390/min14080827 - 15 Aug 2024

Viewed by 396

Abstract

Depending on the ore quality, a washing process can be conducted with the bauxite, which basically consists of scrubbing the ore and screening in order to increase the available alumina grade, i.e., the alumina extractable using the Bayer Process, and reduce the impurity [...] Read more.

Depending on the ore quality, a washing process can be conducted with the bauxite, which basically consists of scrubbing the ore and screening in order to increase the available alumina grade, i.e., the alumina extractable using the Bayer Process, and reduce the impurity content. Tailings are usually disposed of in a tailings dam in the form of a slurry, which is a mixture of solid particles and liquid, consisting mainly of ultra-fine kaolinite, making the dewatering operation challenging. To reduce the environmental impact, mining companies are studying alternative methods to dewater the tailings, and different dewatering methods are available worldwide. The use of new technologies to dewater the tailings has contributed to facing the challenges of achieving sustainable development with their disposal. The decanter centrifuges are already an option for operations for the Canadian oil sands, gold ore in Peru, and nickel in New Caledonia; they are also being tested for iron ore in Brazil. In the present work, bauxite dewatering using the decanter centrifuge was evaluated to understand more about the behavior of these materials and to investigate the effects of various process parameters on the solid recovery and solid content of the flows, using three different kinds of equipment. The results indicated that decanter centrifuges can be used to achieve a high concentration of solids in the cake, with values ranging from 60% to 80% solids per weight and a great clarification in the liquid phase (centrate) from 0 to 6% solids per weight, values which mean the solid phase is suitable for reutilization in the processing circuit. Additionally, the present work provides a better understanding of how different solid contents feed can affect the behavior of the equipment. Full article

(This article belongs to the Section Mineral Processing and Extractive Metallurgy)

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24 pages, 1370 KiB

Open AccessReview

Adsorption of Polycyclic Aromatic Hydrocarbons from Wastewater Using Iron Oxide Nanomaterials Recovered from Acid Mine Water: A Review

by Tumelo M. Mogashane, Johannes P. Maree and Lebohang Mokoena

Minerals 2024, 14(8), 826; https://doi.org/10.3390/min14080826 - 14 Aug 2024

Cited by 1 | Viewed by 447

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are a group of organic pollutants known for their persistence and potential carcinogenicity. Effective removal techniques are required since their presence in wastewater poses serious threats to human health and the environment. In this review study, iron oxide nanomaterials [...] Read more.

Polycyclic aromatic hydrocarbons (PAHs) are a group of organic pollutants known for their persistence and potential carcinogenicity. Effective removal techniques are required since their presence in wastewater poses serious threats to human health and the environment. In this review study, iron oxide nanomaterials (IONs), a by-product of mining operations, recovered from acid mine water are used to investigate the adsorption of PAHs from wastewater. The mechanisms of PAH adsorption onto IONs are investigated, with a focus on the effects of concentration, temperature, and pH on adsorption efficiency. The better performance, affordability, and reusable nature of IONs are demonstrated by comparative studies with alternative adsorbents such as activated carbon. Economic and environmental ramifications highlight the benefits of employing recovered materials, while case studies and real-world applications show how effective IONs are in removing PAHs in the real world. This review concludes by discussing potential future developments in synthesis processes, areas for more research, and emerging trends in nanomaterial-based adsorption. This research intends to contribute to the development of more effective and sustainable wastewater treatment technologies by offering a thorough assessment of the present and future potential of employing IONs for PAH removal from wastewater. Full article

(This article belongs to the Special Issue Acid Mine Drainage: A Challenge or an Opportunity?)

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15 pages, 13694 KiB

Open AccessArticle

Karwowskiite, Ca₉(Fe²⁺_0.5□_0.5)Mg(PO₄)₇—A New Merrillite Group Mineral from Paralava of the Hatrurim Complex, Daba-Siwaqa, Jordan

by Evgeny V. Galuskin, Irina O. Galuskina, Joachim Kusz, Maria Książek, Yevgeny Vapnik and Grzegorz Zieliński

Minerals 2024, 14(8), 825; https://doi.org/10.3390/min14080825 - 14 Aug 2024

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Abstract

Crystals of karwowskiite, Ca₉Mg(Fe²⁺_0.5□_0.5)(PO₄)₇, a new mineral of the merrillite group, were found on an amygdule wall in the central part of an anorthite–tridymite–diopside paralava of the Hatrurim Complex, Daba-Siwaqa, Jordan. The [...] Read more.

Crystals of karwowskiite, Ca₉Mg(Fe²⁺_0.5□_0.5)(PO₄)₇, a new mineral of the merrillite group, were found on an amygdule wall in the central part of an anorthite–tridymite–diopside paralava of the Hatrurim Complex, Daba-Siwaqa, Jordan. The amygdule was filled with a sulfide melt, which after crystallization gave a differentiated nodule, consisting of troilite and pentlandite parts and containing tetrataenite and nickelphosphide inclusions. Karwowskiite crystals are colorless, although sometimes a greenish tint is observed. The mineral has a vitreous luster. The microhardness VHN₂₅ is 365 (12), corresponding to 4 on the Mohs hardness scale. Cleavage is not observed, and fracture is conchoidal. The calculated density is 3.085 g/cm³. Karwowskiite is uniaxial (−): ω = 1.638 (3), ε = 1.622 (3) (λ = 589 nm), and pleochroism is not observed. The composition of karwowskiite is described by the empirical formula: Ca_9.00(□_0.54Fe²⁺_0.23Mg_0.12Na_0.04 Sr_0.03 Ni_0.03K_0.01) _Σ1.00Mg_1.00(PO₄)_7.02. Karwowskiite is distinct from the known minerals of the merrillite subgroup with the general formula A₉XM[TO₃(Ø)]₇, where A = Ca, Na, Sr, and Y; X = Na, Ca, and □; M = Mg, Fe²⁺, Fe³⁺, and Mn; T = P; and Ø = O, in that the X site in it is occupied by Fe²⁺_0.5□_0.5. Karwowskiite is trigonal, space group R-3c with a = 10.3375 (2) Å, c = 37.1443 (9) Å, and V = 3437.60 (17) Å³. Karwowskiite crystallizes at temperatures lower than 1100 °C in a thin layer of secondary melt forming on the walls of amygdules and gaseous channels in paralava as a result of contact with heated gases which are by-products of the combustion process. Full article

(This article belongs to the Collection New Minerals)

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17 pages, 3644 KiB

Open AccessArticle

Density Functional Theory Study of the Crystal Structure and Infrared Spectrum of a Synthetized Ettringite Mineral

by Francisco Colmenero, Ana María Fernández, Oscar Almendros-Ginestà and Tiziana Missana

Minerals 2024, 14(8), 824; https://doi.org/10.3390/min14080824 - 14 Aug 2024

Cited by 1 | Viewed by 341

Abstract

One of the most important hydration phases of Portland cement is ettringite, a calcium sulfo-aluminate mineral (

{C a}_{6} {A l}_{2} {(O H)}_{12} {({SO}_{4})}_{3} \cdot 26 H_{2} O

) showing a great capacity [...] Read more.

One of the most important hydration phases of Portland cement is ettringite, a calcium sulfo-aluminate mineral (

{C a}_{6} {A l}_{2} {(O H)}_{12} {({SO}_{4})}_{3} \cdot 26 H_{2} O

) showing a great capacity of adsorbing radionuclides and other contaminant cationic and anionic species, or incorporating them into its crystal structure. In this work, the X-ray diffraction pattern and infrared spectra of a synthetized ettringite sample are recorded and simulated, employing theoretical methods based on Density Functional Theory. Despite the complexity of this phase, the calculated structure, X-ray diffraction pattern and infrared spectrum are in excellent agreement with their experimental counterparts. Since the calculated and experimental spectra are consistent, the main infrared bands are assigned using a normal coordinate analysis, some of them being completely reassigned with respect to other experimental works. The good agreement found provides strong support for the computational methods employed towards their use for studying the surface adsorption properties and the incorporation of contaminations in its structure. The density of reactive groups at the surfaces of ettringite is reported, and the surface adsorption of water molecules is studied. These surfaces appear to be highly hydrophilic, in agreement with the experimental finding that the ettringite structure may include more water molecules, at least up to 27, one more than in its standard formula. Full article

(This article belongs to the Section Crystallography and Physical Chemistry of Minerals & Nanominerals)

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15 pages, 5780 KiB

Open AccessArticle

The Role of Water Content and Binder to Aggregate Ratio on the Performance of Metakaolin-Based Geopolymer Mortars

by Felix Dathe, Steffen Overmann, Andreas Koenig and Frank Dehn

Minerals 2024, 14(8), 823; https://doi.org/10.3390/min14080823 - 14 Aug 2024

Viewed by 336

Abstract

Geopolymers are in many applications a perfect alternative to standard cements, especially regarding the sustainable development of green building materials. This experimental study therefore deals with the investigation of different factors, such as the water content and the binder to aggregate ratio, and [...] Read more.

Geopolymers are in many applications a perfect alternative to standard cements, especially regarding the sustainable development of green building materials. This experimental study therefore deals with the investigation of different factors, such as the water content and the binder to aggregate ratio, and their influence on the workability of fresh mortar and its mechanical properties and porosity on different size scales. Although increasing the water content improved the workability and flow behaviour of the fresh mortar, at the same time, a reduction in compressive strength in particular and a lesser reduction in flexural strength could be demonstrated. This finding can be attributed to an increase in capillary porosity, as demonstrated by capillary water uptake and mercury intrusion porosimetry measurements. At the same time, the increasing water content led to an improved deaeration effect (low air void content) and to initial segregation (see the µXCT measurements). An alternative approach to enhance the compressive and flexural strengths of the mortar specimens is optimization of the binder to aggregate ratio from 1 to 0.25. This study paves the way for a comprehensive understanding of the underlying chemistry of the geopolymerization reaction and is crucial for the development of sustainable alternatives to cementitious systems. Full article

(This article belongs to the Special Issue Geopolymers: Synthesis, Characterization and Application)

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23 pages, 14079 KiB

Open AccessArticle

Study on Column Leaching Behavior of Low-Grade High Calcium and Magnesium Copper Ore

by Jingyuan Xu, Shuchen Qin, Chaozhen Zheng, Honghong Sun, Baojun Yang, Sanping Liu, Guanzhou Qiu, Derek O. Northwood, Kristian E. Waters and Hao Ma

Minerals 2024, 14(8), 822; https://doi.org/10.3390/min14080822 - 14 Aug 2024

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Abstract

This paper studies the process mineralogy, mechanism, and kinetics of column leaching behavior of low-grade high-calcium–magnesium copper ore. The effect of sulfuric acid concentration, leach solution spraying intensity, and material particle size on column leaching kinetics is discussed. The kinetic analysis of column [...] Read more.

This paper studies the process mineralogy, mechanism, and kinetics of column leaching behavior of low-grade high-calcium–magnesium copper ore. The effect of sulfuric acid concentration, leach solution spraying intensity, and material particle size on column leaching kinetics is discussed. The kinetic analysis of column leaching of copper indicates that sulfuric acid concentration has a significant impact. As sulfuric acid concentration increases, the limiting step of reaction shifts from chemical reaction control to a combination of chemical reaction and diffusion mixing control. Spraying intensity also affects copper column leaching; increasing intensity shifts the limiting step from diffusion control to mixing control, thereby mitigating the effects of diffusion control. Regarding other elements, it is found that iron leaching is primarily controlled by chemical reaction, while calcium leaching is mainly controlled by chemical reaction. As sulfuric acid concentration increases from 10 g/L to 20 g/L, the limiting step for calcium leaching shifts from chemical reaction control to chemical reaction and diffusion-mixing control. Full article

(This article belongs to the Special Issue Recent Advances in Separation Techniques for Critical Minerals/Metals, Circular Economy, and Sustainability)

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15 pages, 14357 KiB

Open AccessArticle

Paleopressure during Hydrocarbon Charging and Its Evolution in the Funing Formation of the Gaoyou Sag, Subei Basin, Eastern China

by Chunquan Li, Shiyou Qian and Yuancai Zheng

Minerals 2024, 14(8), 821; https://doi.org/10.3390/min14080821 - 14 Aug 2024

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Abstract

Abnormally high pressures are currently limited and locally developed in the Funing Formation of the Gaoyou Sag, Subei Basin, eastern China, but the paleopressure and its evolutionary history remain unclear. Based on the determination of hydrocarbon charging periods by performing systematic fluid inclusion [...] Read more.

Abnormally high pressures are currently limited and locally developed in the Funing Formation of the Gaoyou Sag, Subei Basin, eastern China, but the paleopressure and its evolutionary history remain unclear. Based on the determination of hydrocarbon charging periods by performing systematic fluid inclusion analysis on sixteen core samples from the Funing Formation, thermodynamic modeling with fluid inclusion data was adopted to reconstruct the paleopressure and redisplay its evolutionary history throughout geological time. Results showed that the Funing Formation experienced two episodes of hydrocarbon charging periods. Episode 1 occurred with the charging of lower maturity oils in the period from 52.8 Ma to 49.5 Ma, which was recorded by yellow-fluorescing oil inclusions. Episode 2 happened with the charging of higher maturity oils in the period from 47.0 Ma to 37.0 Ma, which was characterized by blue-fluorescing oil inclusions. Each episode was an abnormally high-pressured hydrocarbon charging process. The pressure coefficient of Episode 1 reached as high as 1.44, while that of Episode 2 reached as high as 1.40. The current formation pressure is the evolutionary result of paleopressure after a process of rapid increasing and decreasing and slow increasing and is not as high as what it reached during the hydrocarbon charging periods. This work is valuable for the exploration of conventional clastic oil reservoirs and unconventional shale oils in the Funing Formation. Full article

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30 pages, 12450 KiB

Open AccessArticle

The Early Neoproterozoic Andean-Type Orogenic and Within-Plate Magmatic Events in the Northern Margin of the Yangtze Craton during the Convergence of the Rodinia Supercontinent

by Yunxu Wei, Haiquan Li, Wenxiao Zhou, Changqian Ma, Ernest Chi Fru, Daliang Xu, Xin Deng, Mantang Tan, Xiaoming Zhao, Yang Xu and Hao Liu

Minerals 2024, 14(8), 820; https://doi.org/10.3390/min14080820 - 13 Aug 2024

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Abstract

Although considered a crucial component of the Rodinia supercontinent, it remains uncertain how the Yangtze craton relates to the accretion and breakup of Rodinia. Here, the Huanglingmiao granitic complex (HGC), an intermediate-acid rock series that intruded on the southern Kongling terrane of the [...] Read more.

Although considered a crucial component of the Rodinia supercontinent, it remains uncertain how the Yangtze craton relates to the accretion and breakup of Rodinia. Here, the Huanglingmiao granitic complex (HGC), an intermediate-acid rock series that intruded on the southern Kongling terrane of the northern Yangtze craton margin, is investigated to help resolve this conundrum. Our analysis indicates that these rocks consist of tonalite, trondhjemite, granodiorite, oligoporphyritic granodiorite, porphyric biotite granodiorite, and fine- to medium-grained granodiorite dyke compositions. Collectively, this assemblage is further subdivided into two categories by their temporal, spatial, and geochemical features into early TTG-like and later granitic–dioritic units, which are composed of tonalite, trondhjemite, granodiorite, porphyritic granodiorite, and the fine- to medium-grained granodiorite dykes, respectively. Zircon U-Pb dating yields ages of 865~850 Ma for the TTG-like rocks, 844~825 Ma for the porphyritic granodiorites, and ~800 Ma for the granodiorite dykes. Combined with geochemical evidence, the data suggest that the early- and late-series rocks were formed by a partial melting of Mesoproterozoic and Paleoproterozoic crustal materials, respectively, suggesting that the vertical layering of the crust controlled the composition of the independent units. In addition, isotopic evidence points to different sources for the various rocks in the Kongling terrane and that mantle-derived materials influenced the early-series lithologies. Combined with previous studies on the northern margin of the Yangtze craton, it is inferred that the early-series rocks formed in an active continental margin environment, while the late-series rocks display within-plate boundary formation characteristics. The multiple magmatic activities revealed by this study record sequential partial melting with tectonic transition characteristics from an Andean-type to within-plate magmatism in the northern margin of the Yangtze craton. Taken together, these observations point to a strong association between these rocks, convergence, and incorporation of the northern Yangtze craton margin into the Rodinia supercontinent during the Tonian Period. Full article

(This article belongs to the Section Mineral Geochemistry and Geochronology)

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Minerals, Volume 14, Issue 8 (August 2024) – 114 articles

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