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Volume 15
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Minerals, Volume 15, Issue 10 (October 2025) – 85 articles

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26 pages, 28516 KB  
Article
Geology-Topography Constrained Super-Resolution of Geochemical Maps via Enhanced U-Net
by Yao Pei, Yuanfang Wang, Xiaolong Li, Tie Gao, Shengfa Wang and Xiaoshan Zhou
Minerals 2025, 15(10), 1088; https://doi.org/10.3390/min15101088 (registering DOI) - 19 Oct 2025
Abstract
Geochemical maps are essential visualization tools for studying the distribution patterns of elements on the Earth’s surface. They provide critical insights into geological structure, mineralization processes, and environmental evolution. Traditional interpolation methods often fail to adequately reconstruct high-frequency details in geochemical maps with [...] Read more.
Geochemical maps are essential visualization tools for studying the distribution patterns of elements on the Earth’s surface. They provide critical insights into geological structure, mineralization processes, and environmental evolution. Traditional interpolation methods often fail to adequately reconstruct high-frequency details in geochemical maps with low sampling density. This study proposes a super-resolution (SR) reconstruction method for geochemical maps based on an enhanced U-Net architecture, validated in the Gouli area of Qinghai Province. By integrating residual blocks, multi-scale neural networks, and constraints from topographic features (elevation, slope, aspect) and geological map embeddings, our method enhances the resolution of stream sediment geochemical maps from 1:50,000 to 1:25,000 scale. Experimental results demonstrate that the proposed method outperforms SRCNN, VDSR, and standard U-Net models in both peak signal-to-noise ratio (PSNR) and structural similarity index (SSIM). Specifically, with all constraints incorporated, the method achieves maximum and mean PSNR values of 38.486 and 25.334, respectively, and maximum and mean SSIM values of 0.968 and 0.817. The reconstructed high-resolution (HR) geochemical maps exhibit superior detail clarity and maintain strong spatial correlation with the original HR data. Studies have shown that this method can effectively learn multi-scale geochemical patterns and detect subtle anomalies missed in low-resolution (LR) maps. Moreover, the reconstructed HR geochemical maps exhibit better alignment with the Ag, Cu, and Pb anomalies in known mineralization zones (Maixiulongwa and Sanchakou areas), thereby providing strong support for precise mineral exploration. Full article
(This article belongs to the Special Issue Selected Papers from the 7th National Youth Geological Congress)
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17 pages, 1601 KB  
Article
Research on the Mechanical and Microstructure Characteristics of Cemented Paste Backfill in Deep In Situ Environments
by Yin Chen, Zepeng Yan, Guoqiang Wang, Lijie Guo, Yunwei Zhang, Yue Zhao and Chong Jia
Minerals 2025, 15(10), 1087; https://doi.org/10.3390/min15101087 (registering DOI) - 18 Oct 2025
Abstract
Backfilling mining methods control the surrounding pressure and ground subsidence by backfilling goaf and managing the ground pressure, providing a safety guarantee for mining in complex environments and serving as a key means of achieving the deep mining of metal minerals. However, in [...] Read more.
Backfilling mining methods control the surrounding pressure and ground subsidence by backfilling goaf and managing the ground pressure, providing a safety guarantee for mining in complex environments and serving as a key means of achieving the deep mining of metal minerals. However, in the design of backfill strength, material mix ratios are determined under indoor standard constant temperature and humidity conditions, which differ significantly from the in situ curing environment. Strength measurements obtained from field samples are notably higher than those from indoor test specimens. To address this issue, this study designed a curing device simulating the in situ thermal-hydraulic multi-field environment of the mining site and tested the strength and porosity of the backfill under different curing temperatures, curing pressures, and pore water pressures. The results indicate that curing pressure and pore water pressure significantly altered the pore structure of the specimens. Specifically, when the curing pressure increased to 750 kPa, the maximum pore diameter decreased from 3110.52 nm to approximately 2055 nm, accompanied by a continuous reduction in porosity. Pore water pressure exhibited a positive linear correlation with specimen porosity, which increased continuously as the pore water pressure rose. With increasing curing temperature, the strength of the backfilled specimens first increased and then decreased, reaching a maximum at 45 °C. As the curing pressure increased, the strength of the backfilled specimens rose, but the rate of increase gradually slowed. With increasing pore water pressure, the strength of the backfilled specimens showed a gradual decreasing trend. Full article
(This article belongs to the Special Issue Advances in Mine Backfilling Technology and Materials, 2nd Edition)
32 pages, 9494 KB  
Article
Mineral Prospectivity Maps for Critical Metals in the Clean Energy Transition: Examples for Hydrothermal Copper and Nickel Systems in the Carajás Province
by Luiz Fernandes Dutra, Lena Virgínia Soares Monteiro, Marco Antonio Couto, Jr. and Cleyton de Carneiro Carneiro
Minerals 2025, 15(10), 1086; https://doi.org/10.3390/min15101086 (registering DOI) - 18 Oct 2025
Abstract
Machine learning algorithms are essential tools for developing Mineral Prospectivity Models (MPMs), enabling a data-driven approach to mineral exploration. This study integrated airborne geophysical, topographic, and geological data with a mineral system framework to build MPMs for iron oxide–copper–gold (IOCG) and hydrothermal nickel [...] Read more.
Machine learning algorithms are essential tools for developing Mineral Prospectivity Models (MPMs), enabling a data-driven approach to mineral exploration. This study integrated airborne geophysical, topographic, and geological data with a mineral system framework to build MPMs for iron oxide–copper–gold (IOCG) and hydrothermal nickel deposits in the Southern Copper Belt of the Carajás Province, Brazil. Seven machine learning algorithms were tested using stratified 10-fold cross-validation: Logistic Regression, k-Nearest Neighbors, AdaBoost, Support Vector Machine (SVM), Random Forest, XGBoost, and Multilayer Perceptron. SVM delivered the highest classification accuracy and robustness, highlighting new mineralized zones while minimizing false positives and negatives, and accounting for geological complexity. SHapley Additive ExPlanations (SHAP) analysis revealed that structural controls (e.g., faults, shear zones, and geochronological contacts) exert a stronger influence on mineralization patterns than lithological factors. The resulting prospectivity maps identified geologically distinct zones of IOCG and hydrothermal nickel mineralization, with high-probability closely aligned with major structural corridors oriented E–W, NE–SW, and NW–SE. Results also suggest an indirect association with volcanic units, Orosirian A1-type granites and Neoarchean A2-type granites. Full article
(This article belongs to the Special Issue Global Mineral Resource Exploration Using Multi-Sensor Satellite Data and Machine Learning Algorithms)
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28 pages, 8674 KB  
Article
Petrogenesis of the Chamuhan Intrusion in the Southern Great Xing’an Range: Constraints from Zircon U-Pb Dating and Petrogeochemistry
by Yutong Song, Gongzheng Chen, Guang Wu, Tiegang Li, Tong Zhang, Jinfang Wang, Yingjie Li, Chenyu Liu, Yuze Li and Yinlong Wang
Minerals 2025, 15(10), 1085; https://doi.org/10.3390/min15101085 (registering DOI) - 18 Oct 2025
Abstract
The Southern Great Xing’an Range (SGXR), an important W–Sn polymetallic metallogenic belt in northern China, hosts multiphase magmatism and has witnessed recent discoveries of multiple tungsten–tin polymetallic deposits. The W–Sn mineralization in this area is intimately associated with Early Cretaceous highly fractionated granites. [...] Read more.
The Southern Great Xing’an Range (SGXR), an important W–Sn polymetallic metallogenic belt in northern China, hosts multiphase magmatism and has witnessed recent discoveries of multiple tungsten–tin polymetallic deposits. The W–Sn mineralization in this area is intimately associated with Early Cretaceous highly fractionated granites. The Chamuhan deposit, a small-sized W–Mo polymetallic deposit in SGXR, is genetically linked to a concealed fine-grained porphyritic alkali feldspar granite intrusion. In this study, we present the LA-ICP-MS zircon U-Pb ages, whole-rock geochemical, and electron probe microanalysis (EPMA) mineral chemistry to constrain the petrogenesis and metallogenic implications of this granite. Zircon U–Pb dating yields a crystallization age of 141.3 ± 1.2 Ma, consistent with molybdenite Re–Os ages. The granite is characterized by elevated SiO2 (76.9–79.1 wt%) and total alkalis (7.3–8.5 wt%), and exhibits peraluminous high-K calc-alkaline affinity (A/CNK = 1.37–1.57). Geochemical signatures reveal enrichment in large ion lithophile elements (LILEs, e.g., Rb, Th, U) coupled with depletion in high-field strength elements (HFSEs, e.g., Ba, Sr, P, Eu, Ti, Nb, Ta), and are accompanied by right-sloping REE patterns with LREE enrichment and HREE depletion. EPMA data indicate that the mica in the intrusion is primarily zinnwaldite and Li-rich phengite, whereas the plagioclase occurs as albite. The feldspar thermobarometry yields crystallization temperatures of 689–778 °C and 313 MPa–454 MPa, while the melt H2O content and oxygen fugacity are 8.61 wt–11.1 wt% and −22.58–−14.48, respectively. These geochemical signatures indicate that the granites are highly fractionated I-type granites with extensive fractional crystallization of various minerals like plagioclase, K-feldspar, and apatite, etc. From the Late Jurassic to the Early Cretaceous, the subduction and rollback of the Paleo-Pacific Ocean plate resulted in extensional tectonic environments in eastern China. Asthenospheric upwelling and lower crustal melting generated parental magmas, wherein progressive fractional crystallization during ascent concentrated ore-forming elements and volatiles within residual melts. This process played a key role in the formation of the Chamuhan deposit, exemplifying the metallogenic potential of highly evolved granitic systems in the SGXR. Full article
(This article belongs to the Special Issue Igneous Rocks and Related Mineral Deposits)
16 pages, 4179 KB  
Article
Hydrometallurgical Recovery of Critical Metal Indium from Scrap LCD Panels
by Karina Rani, Rekha Panda, Ankur Sharma, Alok Kumar Meher, Balram Ambade, Kyoungkeun Yoo and Manis Kumar Jha
Minerals 2025, 15(10), 1084; https://doi.org/10.3390/min15101084 (registering DOI) - 18 Oct 2025
Abstract
Indium, widely used in indium–tin oxide (ITO) coatings for liquid crystal displays (LCDs), is a scarce and strategically important metal with increasing demand. Recycling waste LCD panels offers an efficient secondary source to address supply risks and environmental concerns. In this study, a [...] Read more.
Indium, widely used in indium–tin oxide (ITO) coatings for liquid crystal displays (LCDs), is a scarce and strategically important metal with increasing demand. Recycling waste LCD panels offers an efficient secondary source to address supply risks and environmental concerns. In this study, a hydrometallurgical flow sheet was developed under mild conditions for indium (In) recovery. Leaching trials with sulphuric acid at varying concentrations, pulp densities, temperatures, and times showed that 5% H2SO4 (v/v) with 100 g/L pulp density at 60 °C for 30 min achieved ~98% dissolution of In, while minimizing the co-leaching of Al and Sn. Kinetic analysis indicated a diffusion-controlled mechanism for In dissolution with an activation energy of 21.2 kJ mol−1. The leached liquor was further purified through solvent extraction by 20% Cyanex 921 (v/v), achieving optimum In extraction at pH 2.5 with an organic-to-aqueous phase ratio of 1/3, reaching equilibrium within 15 min. The McCabe–Thiele plot shown indicates the complete In extraction in two stages. FT-IR studies confirmed the In-extractant bonding at optimized conditions. 10% H2SO4 (v/v) was used for the stripping of In from the loaded organic, ensuring nearly complete back-transfer of indium with excellent phase separation. The integrated process yielded ~97% In recovery in stripping. The pure salt of Indium could be obtained by evaporation/crystallization of pure indium solution. The developed process has the potential to be transferred for commercial exploitation after scale-up and pilot trial. Full article
(This article belongs to the Special Issue Application of Nanomaterials in Mineral Processing)
21 pages, 4324 KB  
Article
The Efficiency of Fibrous Mg Clays for the Removal of Ciprofloxacine and Lidocaine from Water—The Role of Associated Clay Minerals
by Telma Belén Musso, Maria Eugenia Roca-Jalil, Vanina Rodriguez-Ameijide, Micaela Sanchez, Andrea Maggio, Miria Teresita Baschini, Gisela Pettinari, Luis Villa, Alejandro Pérez-Abad and Manuel Pozo
Minerals 2025, 15(10), 1083; https://doi.org/10.3390/min15101083 - 17 Oct 2025
Abstract
Adsorption studies of ciprofloxacine (CPX) and lidocaine (LID) emerging contaminants were performed on two fibrous Mg clays from the Madrid basin and Senegal. The samples were characterized by X-ray diffraction, ICP major element analysis, infrared spectroscopy, thermal analysis, optical petrography, scanning and transmission [...] Read more.
Adsorption studies of ciprofloxacine (CPX) and lidocaine (LID) emerging contaminants were performed on two fibrous Mg clays from the Madrid basin and Senegal. The samples were characterized by X-ray diffraction, ICP major element analysis, infrared spectroscopy, thermal analysis, optical petrography, scanning and transmission electron microscopy, cation exchange capacity (CEC), and N2-BET analysis. Two mineral assemblages were established. Assemblage 1 mainly consists of sepiolite and minor trioctahedral smectite, while assemblage 2 is mostly composed of palygorskite, which is associated with dioctahedral smectite. The sorption was fast and reached equilibrium in 2 h. Fibrous Mg clays showed a higher adsorption capacity for CPX than for LID in the conditions studied. CPX adsorption on sepiolite and palygorskite can be the result of the combination of various mechanisms: ion exchange with permanently charged sites, electrostatic attractions with external surfaces, and an inner sphere complex with broken edges. LID adsorption mainly occurs by ion exchange and electrostatic interaction with the external surfaces of the clays. Dioctahedral smectite, as an associated phase, contributed to a higher removal percentage in palygorskite samples. By contrast, the trioctahedral smectite did not play a significant role in the adsorption of the samples with sepiolite. The mesoporous structure, high surface area, and moderate cation exchange of fibrous clays play a key role in the sorption process of CPX and LID. Full article
(This article belongs to the Collection Clays and Other Industrial Mineral Materials)
18 pages, 2949 KB  
Article
Artificial Aggregates from Metallurgical Waste as a Potential Source of Groundwater and Soil Contamination
by Katarzyna Nowińska, Jacek Nowak, Aleksandra Bartyzel, Magdalena Kokowska-Pawłowska and Krzysztof Kuliński
Minerals 2025, 15(10), 1082; https://doi.org/10.3390/min15101082 - 17 Oct 2025
Abstract
Highly developed countries generate large volumes of industrial waste, the type and quantity of which are strongly linked to the characteristics of the industries that produce it. Industrial waste can adversely affect the environment, so its disposal and management are a major challenge. [...] Read more.
Highly developed countries generate large volumes of industrial waste, the type and quantity of which are strongly linked to the characteristics of the industries that produce it. Industrial waste can adversely affect the environment, so its disposal and management are a major challenge. Understanding the characteristics of a given waste type (e.g., its chemical and phase composition, technical parameters and likelihood of releasing constituents into aquatic and soil environments) allows its potential economic applications to be determined. A simple application of mineral waste is in the production of artificial aggregates, which are increasingly used as a substitute for natural aggregates. In Poland, artificial aggregates are widely produced from metallurgical waste from steel and non-ferrous metallurgy, which may contain numerous components that are potentially environmentally damaging. Depending on their occurrence form (i.e., mineral composition), these contaminants have varying potential to be released into aquatic and soil environments. This study presents the results of mineral and chemical composition analyses and leachability tests conducted on aggregates produced from metallurgical waste, including slags from blast furnaces, steelmaking, Zn and Pb production, and Ni production. The studied aggregates are characterised by chemical and phase composition differences, resulting from the type of slag from which they originate. The chemical composition of blast furnace slag is dominated by CaO, SiO2, Fe2O3, and MgO; steelmaking slag by CaO, Fe2O3, and SiO2; Zn and Pb production slag by SiO2, Fe2O3, SO3, and CaO; and Ni production slag by SiO2, Fe2O3, CaO, and Al2O3. The phase composition of all the tested aggregates is dominated by silicates resistant to leaching (weathering), which results in low levels of Al, Ca, Cr, Mn, Zn, Pb, Cu, As, Sr and Ni leaching, not exceeding 1.6%. Full article
(This article belongs to the Special Issue Characterization and Reuse of Slag)
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20 pages, 6663 KB  
Article
Geology and Hydrothermal Evolution of the Antas North Iron Sulfide–Copper–Gold (ISCG) Deposit in the Carajás Mineral Province
by Sérgio Roberto Bacelar Hühn, Rafael Nascimento Paula, Francisco José Ferreira Fonseca and Isac Brito Barreira
Minerals 2025, 15(10), 1081; https://doi.org/10.3390/min15101081 - 17 Oct 2025
Abstract
The Antas North mine, located in the southeastern Amazonian Craton within the Carajás Mineral Province, is hosted by mafic and felsic metavolcanic rocks that have undergone extensive hydrothermal alteration. Field and petrographic data reveal a hydrothermal sequence comprising sodic (albite), potassic (biotite + [...] Read more.
The Antas North mine, located in the southeastern Amazonian Craton within the Carajás Mineral Province, is hosted by mafic and felsic metavolcanic rocks that have undergone extensive hydrothermal alteration. Field and petrographic data reveal a hydrothermal sequence comprising sodic (albite), potassic (biotite + scapolite), calcic (amphibole + apatite), silicification (quartz), and propylitic (chlorite + epidote + calcite) assemblages. Copper–gold mineralization, spatially associated with calcic alteration, occurs as massive sulfide lenses, breccia zones, and vein networks dominated by chalcopyrite, pyrrhotite, and pyrite. The absence of magnetite/hematite and the dominance of sulfides and ilmenite classify Antas North as an Iron Sulfide–Copper–Gold (ISCG) system, representing a reduced endmember within the broader IOCG spectrum. New U–Pb titanite geochronology yields two concordant age populations at ca. 2476.6 ± 15.9 Ma Ga and 2162.9 ± 28.1 Ma Ga, recording a late Archean mineralizing stage and subsequent Paleoproterozoic reactivation during the Transamazonian orogeny. These ages parallel the multistage evolution recognized in other Carajás IOCG deposits, where copper–gold-related mineralization was repeatedly overprinted by later tectono-hydrothermal events. The reduced character of Antas North, marked by ilmenite and sulfide dominance with scarce magnetite, demonstrates that reduced IOCG styles were already established in the Neoarchean–Paleoproterozoic transition and underscores the diversity of mineralizing processes within the Carajás IOCG–IOA spectrum. Full article
(This article belongs to the Special Issue Novel Methods and Applications for Mineral Exploration, Volume III)
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30 pages, 1516 KB  
Review
Perspectives for High-Purity Quartz from European Resources
by Kalyani Mohanty, Pura Alfonso, Josep Oliva, Carlos Hoffmann Sampaio and Hernan Anticoi
Minerals 2025, 15(10), 1080; https://doi.org/10.3390/min15101080 - 16 Oct 2025
Viewed by 126
Abstract
High-purity quartz (HPQ) is a critical raw material for advanced technologies including semiconductors, photovoltaic cells, and optical fibers. This study reviews the geological occurrence, beneficiation routes, and strategic significance of HPQ within the European context. Quartz processing follows a sequential flowsheet of comminution, [...] Read more.
High-purity quartz (HPQ) is a critical raw material for advanced technologies including semiconductors, photovoltaic cells, and optical fibers. This study reviews the geological occurrence, beneficiation routes, and strategic significance of HPQ within the European context. Quartz processing follows a sequential flowsheet of comminution, magnetic separation, flotation, acid leaching, and thermal treatment, designed to remove mineral impurities such as Fe, Al, Ti, and mica. The resulting ultra-high-purity quartz (UHPQ) achieves the chemical and physical specifications required for high-tech industries. Quartz, which is the most common mineral on Earth, can be found in a variety of geological locations such as granitic rocks and pegmatites in the Variscan Belt, metamorphic quartzites, hydrothermal veins, and Pleistocene periglacial and aeolian sediments. Case studies of European deposits demonstrate that geological origin directly influences processing requirements, and that tailored beneficiation strategies are essential to unlock viable resources. To our knowledge, this is the first Europe-focused synthesis that links these findings with the EU Critical Raw Materials Act, the work that emphasizes the potential for domestic HPQ development to strengthen European supply chain resilience, reduce dependence on imports, and support the transition to a green and digital economy. Full article
(This article belongs to the Special Issue Physicochemical Properties and Purification of Quartz Minerals)
28 pages, 5462 KB  
Article
Provenance and Uranium Sources in the Lower Cretaceous Huanhe Formation of Northern Ordos Basin: Constraints from Detrital Zircon U–Pb Geochronology and Hf Isotopes
by Xin Zhang, Junfan Che, Fengjun Nie, Aisheng Miao, Zhaobin Yan, Chengyong Zhang and Yujie Hu
Minerals 2025, 15(10), 1079; https://doi.org/10.3390/min15101079 - 16 Oct 2025
Viewed by 116
Abstract
The Ordos Basin is a key district for sandstone-hosted uranium, yet host-rock controls and uranium sources remain debated. We integrate measured sections, whole-rock geochemistry, and detrital zircon U-Pb-Lu-Hf data from the Cretaceous Huanhe Formation (Yihewusu, northern Ordos) to resolve provenance, transport, and enrichment [...] Read more.
The Ordos Basin is a key district for sandstone-hosted uranium, yet host-rock controls and uranium sources remain debated. We integrate measured sections, whole-rock geochemistry, and detrital zircon U-Pb-Lu-Hf data from the Cretaceous Huanhe Formation (Yihewusu, northern Ordos) to resolve provenance, transport, and enrichment pathways. Uranium enrichment is concentrated in feldspathic-lithic sandstones deposited in proximal fluvial-lacustrine settings. Detrital zircon ages define three clusters—Phanerozoic (500–200 Ma), Paleoproterozoic (2000–1700 Ma), and Neoarchean (2600–2300 Ma)—with Proterozoic grains >60%, indicating derivation from Archean–Paleoproterozoic TTG gneisses, granulites, and khondalites of the Yinshan Block and the northern Central Orogenic Belt. Zircon εHf(t) values (−10.84 to +7.76) and crustal model ages (3.2–2.1 Ga) record substantial Meso- to Neoarchean crustal growth in the source terranes. Critically, Permian-Cretaceous intermediate-felsic igneous rocks along the northern margin of the Western North China Block—marked by elevated U, Th/U > 5 (indicative of U loss), pervasive feldspar micro-fractures, and proximity to basin-margin uranium belts—are identified as the principal uranium reservoirs. We propose a dual uranium supply: soluble uranium mobilized from leached igneous rocks during weathering and fluid-rock interaction, and U-enriched detritus delivered to the basin. Uranium concentrated in redox-sensitive, feldspathic-lithic sandstones of the Huanhe Formation, which effectively trapped advected uranium at proximal facies transitions. These findings establish a direct genetic link between basin-margin uranium sources and in-basin mineralization, providing a predictive framework for regional uranium exploration in North China. Full article
(This article belongs to the Section Mineral Geochemistry and Geochronology)
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16 pages, 3435 KB  
Article
Modeling of an Ideal Solar Evaporation Pond for Lithium Extraction from Brines
by Manuel Silva, María C. Ruiz, Diego Toro and Rafael Padilla
Minerals 2025, 15(10), 1078; https://doi.org/10.3390/min15101078 - 16 Oct 2025
Viewed by 91
Abstract
In the coming decades, anticipated population growth is projected to escalate the demand for essential resources such as NaCl, KCl, and LiCl, which are critical for human consumption, agriculture, and battery production. A substantial proportion of these salts is produced from brines using [...] Read more.
In the coming decades, anticipated population growth is projected to escalate the demand for essential resources such as NaCl, KCl, and LiCl, which are critical for human consumption, agriculture, and battery production. A substantial proportion of these salts is produced from brines using solar evaporation ponds. This article presents a one-dimensional surrogate mathematical model of an ideal solar evaporation pond working at a steady state. The ideal pond considers only water evaporation, with a uniform evaporation rate per unit area. The model’s equation, or the ideal solar evaporation law, allows calculating the ion concentration profile in an ideal pond just given the feed and discharge concentrations. The validation of the law was conducted with industrial data collected in the year 2023 in a lithium recovery plant throughout 15 ponds in series at the Salar de Atacama, Chile. The results verified that the model could accurately predict the monthly concentration profiles (R2 in the range 0.9646 to 0.9864) if lithium does not precipitate in the pond. The model provides accurate values of pond inventories and area requirements for designing stages. The model’s relevance extends beyond the lithium industry to encompass any solar evaporation processes for salt recovery or solution concentration. Full article
(This article belongs to the Special Issue Extraction of Valuable Elements from Salt Lake Brine)
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64 pages, 7773 KB  
Article
Evolution of a Late Carboniferous Fluvio-Lacustrine System in an Endorheic Basin: Multiproxy Insights from the Ludwikowice Formation, Intra-Sudetic Basin (SW Poland, NE Bohemian Massif)
by Aleksander Kowalski, Jolanta Dąbek-Głowacka, Grzegorz J. Nowak, Anna Górecka-Nowak, Urszula Wyrwalska, Magdalena Furca and Patrycja Wójcik-Tabol
Minerals 2025, 15(10), 1077; https://doi.org/10.3390/min15101077 - 15 Oct 2025
Viewed by 124
Abstract
Fluvio-lacustrine systems are highly dynamic continental environments, often developing in tectonically controlled, endorheic basins where sedimentation reflects the interplay of fluvial processes, lake-level fluctuations, climate, and subsidence. The main aim of this paper is to reconstruct the depositional architecture and paleogeographic evolution of [...] Read more.
Fluvio-lacustrine systems are highly dynamic continental environments, often developing in tectonically controlled, endorheic basins where sedimentation reflects the interplay of fluvial processes, lake-level fluctuations, climate, and subsidence. The main aim of this paper is to reconstruct the depositional architecture and paleogeographic evolution of the Ludwikowice Formation (Intra-Sudetic Basin, NE Bohemian Massif), which preserves a high-resolution record of a late Carboniferous (late Gzhelian) fluvio-lacustrine system. The formation developed as a fining-upward megacyclothem documenting the transition from proximal alluvial and fluvial fan deposits to distal, organic-rich lacustrine facies referred to as the Lower Anthracosia Shale (LAS). This study integrates lithological data from 92 archival boreholes with high-resolution sedimentological, geochemical, petrological, palynological, and magnetic susceptibility analyses from two fully cored reference sections (Ścinawka Średnia PIG-1 and Rybnica Leśna PIG-1) and selected exposures. Nine facies associations (FA1–FA9) have been identified within the formation, including fluvial, sandy to muddy floodplain, aeolian, playa lake margin/coastal mudflat, nearshore, delta plain, subaqueous delta front and subaqueous fan, prodelta, and open lake. The succession shows progressive thickening into narrow, NW–SE-trending depocenters associated with possible strike-slip faulting. Geochemical and isotopic data indicate alternating hydrologically open and closed lake conditions, while magnetic susceptibility reflects climatically driven variations in detrital influx and microbial activity. Organic petrography and palynofacies analyses reveal redox-controlled maceral associations. The Ludwikowice Formation constitutes a detailed archive of Late Paleozoic environmental change and provides new insights into sedimentation and organic matter preservation in intramontane endorheic basins. Our results highlight the response of fluvio-lacustrine systems to climatic and tectonic factors and provide a framework for interpreting analogous successions throughout the stratigraphic record. Full article
(This article belongs to the Special Issue Deep-Time Source-to-Sink in Continental Basins)
20 pages, 3959 KB  
Article
Hydrothermal Fluids and Diagenesis of Mississippian Carbonates: Implications for Regional Mineralization in Western Kansas, U.S.A
by Sahar Mohammadi
Minerals 2025, 15(10), 1076; https://doi.org/10.3390/min15101076 - 15 Oct 2025
Viewed by 214
Abstract
Hydrothermal fluids altered Mississippian (Osagian) carbonates in the Rebecca K. Bounds (RKB) core in western Kansas, U.S.A. Carbonate mineralization is similar to that associated with Mississippian valley type (MVT) mineralization. The RKB core displays fractures, vugs, channels, and breccias filled with saddle dolomite [...] Read more.
Hydrothermal fluids altered Mississippian (Osagian) carbonates in the Rebecca K. Bounds (RKB) core in western Kansas, U.S.A. Carbonate mineralization is similar to that associated with Mississippian valley type (MVT) mineralization. The RKB core displays fractures, vugs, channels, and breccias filled with saddle dolomite and blocky calcite cements. Homogenization temperature indicates that dolomite (65 to 126 °C, 18.4 to 23 wt. % NaCl) and calcite (67 to 101 °C, 13.2 to 22.4 wt. % NaCl) cements were precipitated by hot, saline fluids. These data are consistent with previous studies on the southern midcontinent. Carbon and oxygen isotope values for dolomite (δ13C 0.15 to 2.08‰, δ18O −6.44 to −4.66‰) and calcite (δ13C −1.01 to 1.79‰, δ18O −9.44 to −8.69‰) indicate multiple pulses of fluids likely sourced from basins to the south and west. Strontium isotopes data (0.7088812 to 0.7094432 in dolomite and 0.7089503 to 0.7111501 in calcite) indicate fluid interaction with granitic basement or basement-derived siliciclastics. These results are consistent with mixing of upwelling Ordovician-sourced fluids and Permian evaporitic brines, transported by advective and/or vertical migration. Although sulfide minerals were not observed in this study, earlier reports in western Kansas document sphalerite linked to hydrothermal brines in underlying strata. This study highlights the potential for MVT mineralization in the Mississippian of western Kansas. Full article
(This article belongs to the Special Issue Geochemistry and Genesis of Hydrothermal Ore Deposits, 2nd Edition)
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18 pages, 2486 KB  
Review
Geochemical Characteristics and Health Risks of Coal Dust: An Integrated Review from Component-Dependent Toxicity to Emerging Oxidative Toxicity Indicators
by Xiujuan Feng and Jing Yang
Minerals 2025, 15(10), 1075; https://doi.org/10.3390/min15101075 - 15 Oct 2025
Viewed by 233
Abstract
Coal mining and consumption, a persistent source of global energy, pose significant occupational health risks. Through a bibliometric analysis of 562 publications (2001–2025), this review delineates the evolution from conventional metrics (mass concentration, free silica content) toward advanced characterization of mineralogical/geochemical heterogeneity and [...] Read more.
Coal mining and consumption, a persistent source of global energy, pose significant occupational health risks. Through a bibliometric analysis of 562 publications (2001–2025), this review delineates the evolution from conventional metrics (mass concentration, free silica content) toward advanced characterization of mineralogical/geochemical heterogeneity and component dependent toxicity mechanisms. Evidence confirms that multiple toxic elements are enriched in the respirable fraction, with bioaccessibility critically governed by particle size, host phase, and chemical speciation. In vitro studies using simulated lungs and gastrointestinal fluids demonstrate that acidic environments significantly accelerate toxic metal dissolution, triggering oxidative stress. While the bioaccessibility of inorganic constituents has been extensively studied, that of complex organic pollutants, particularly polycyclic aromatic hydrocarbons, remains a critical knowledge gap. Oxidative stress is now recognized as a pivotal mechanism linking coal dust exposure to inflammation and genotoxic damage. Emerging abiotic toxicity indicators, such as environmentally persistent free radicals and oxidative potential, offer promising avenues for understanding and risk prediction; however, their analytical methodologies require further standardization and refinement. This review provides a scientific foundation for developing a next-generation risk assessment framework that integrates multi-dimensional coal dust characteristics, bioaccessibility, and oxidative potential, thereby guiding future research to better protect the health of coal miners. Full article
(This article belongs to the Special Issue Risks Assessment, Management and Control of Mining Contamination, 2nd Edition)
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1 pages, 122 KB  
Correction
Correction: Sun et al. Formation Mechanism of Plagioclase–Amphibole and Amphibole–Spinel Symplectites in the Bijigou Layered Intrusion: Insights from Mineralogical and Crystallographic Constraints. Minerals 2025, 15, 433
by Baoqun Sun, Xinyu Wei and Huan Dong
Minerals 2025, 15(10), 1074; https://doi.org/10.3390/min15101074 - 15 Oct 2025
Viewed by 66
Abstract
In the published publication [...] Full article
(This article belongs to the Section Mineral Geochemistry and Geochronology)
29 pages, 14958 KB  
Review
A Review on Lithium Extraction Processes from Spodumene and Resource Utilization of the Generated Lithium Slag
by Yongjie Bu, Wenxuan Yan, Xingxing Deng, Sen Huang, Aihui Sun, Qingjun Guan, Shuang Zhou, Wenqing Peng, Weijun Wang, Peng Ge and Yue Yang
Minerals 2025, 15(10), 1073; https://doi.org/10.3390/min15101073 - 14 Oct 2025
Viewed by 136
Abstract
The booming new energy industry has fueled a surge in global lithium demand, with the annual demand for lithium carbonate (Li2CO3) equivalent (LCE) projected to reach 11.2 million tons by 2050. As a key raw material for lithium extraction, [...] Read more.
The booming new energy industry has fueled a surge in global lithium demand, with the annual demand for lithium carbonate (Li2CO3) equivalent (LCE) projected to reach 11.2 million tons by 2050. As a key raw material for lithium extraction, spodumene generates approximately 10–15 tons of lithium slag per ton of lithium carbonate (Li2CO3) produced. However, the comprehensive utilization rate of lithium slag in China remains below 30%, and most of it is disposed of through landfilling, posing soil pollution risks. This review summarizes the main lithium extraction processes from spodumene: the sulfuric acid method (with a lithium recovery rate of over 96% but high acid consumption); alkali processes (achieving 96%–99% lithium recovery and featuring low equipment corrosion, yet with untested applicability to low-grade ores); salt roasting (simplifying purification processes but only achieving ~60% sulfate recovery); and chlorination roasting (with a lithium recovery rate of over 95% but requiring strict safety controls). Additionally, this review covers the resource utilization of lithium slag: 8–10 million tons of gypsum can be recovered annually (filling 16%–20% of China’s industrial by-product gypsum supply gap); the silica–alumina micro-powder can enhance concrete strength and reduce glass fiber production costs; and over 94% of tantalum (Ta) and niobium (Nb) can be recovered from fine tantalite concentrate slag. Key research gaps and future development directions are also identified to support the low-carbon development of the lithium industry. Full article
(This article belongs to the Special Issue Selected Papers from the 7th International Conference of Young Scholars in Mineral Processing)
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18 pages, 2009 KB  
Article
The Recycling of Plastics and Current Collector Foils from End-of-Life NMC-LCO Type Electric Vehicle Lithium-Ion Batteries Using Selective Froth Flotation
by Fulya Mennik, Nazlım İlkyaz Dinç, Beril Tanç Kaya, Zoran Štirbanović, Ronghao Li and Fırat Burat
Minerals 2025, 15(10), 1072; https://doi.org/10.3390/min15101072 - 14 Oct 2025
Viewed by 323
Abstract
The recent increase in end-of-life (EoL) lithium-ion batteries (LiBs) has become a significant concern worldwide. Most studies in the literature have primarily focused on recovering cathode active metals from black mass (BM), whereas the separation of anode–cathode foils, plastics, and casing metals which [...] Read more.
The recent increase in end-of-life (EoL) lithium-ion batteries (LiBs) has become a significant concern worldwide. Most studies in the literature have primarily focused on recovering cathode active metals from black mass (BM), whereas the separation of anode–cathode foils, plastics, and casing metals which are the essential components of LiBs has received relatively little attention. To reduce costs and maximize the recovery of valuable metals in subsequent hydrometallurgical or pyrometallurgical processes, EoL LiBs require appropriate pre-treatment. This study aims to scrape off the BM adhering to the electrode foils resulting from gradual crushing and subsequently separate the plastics and copper (Cu) from other metals through a two-step selective flotation process. The results demonstrated that plastics, due to their natural hydrophobicity, could be effectively removed using a frother, achieving more than 95% recovery with less than 5% metallic contamination. Following plastic flotation, Cu particles were floated in the presence of 3418A, yielding a Cu concentrate containing 65.13% Cu with a recovery rate of 96.4%. Additionally, the aluminum (Al) content in the non-floating material, remaining in the cell, increased to approximately 77%. Full article
(This article belongs to the Special Issue Mineral Processing and Recycling Technologies for Sustainable Future)
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26 pages, 5245 KB  
Article
Sedimentary Environment and Organic Matter Enrichment of the First Member in the Upper Triassic Xujiahe Formation, Southeastern Sichuan Basin
by Hao Huang, Zhongyun Chen, Tingshan Zhang, Xi Zhang and Jingxuan Zhang
Minerals 2025, 15(10), 1071; https://doi.org/10.3390/min15101071 - 13 Oct 2025
Viewed by 245
Abstract
The Xujiahe Formation (FM) is a significant source rock layer in the Sichuan Basin. In recent years, a growing number of scholars believe that the shale gas potential of the Xujiahe Formation is equally substantial, with the first member of the formation being [...] Read more.
The Xujiahe Formation (FM) is a significant source rock layer in the Sichuan Basin. In recent years, a growing number of scholars believe that the shale gas potential of the Xujiahe Formation is equally substantial, with the first member of the formation being the richest resource. The deposition of Member (Mbr) 1 of Xujiahe FM represents the first and most extensive transgression event within the entire Xujiahe Formation. This study investigates the sedimentary environment and organic matter (OM) enrichment mechanisms of the dark mud shales in the Mbr1 of Xujiahe FM on the southeastern margin of the Sichuan Basin, utilizing methods such as elemental geochemistry and organic geochemistry analyses. The results indicate that these dark mud shales possess a relatively high OM abundance, averaging 2.20% and reaching a maximum of 6.22%. The OM is primarily Type II2 to Type III. Furthermore, the paleoclimate during the Mbr1 period in the study area was warm and humid with lush aquatic vegetation. Intense weathering and ample precipitation transported large amounts of nutrients into the lacustrine/marine basin, promoting the growth and reproduction of algae and terrestrial plants. Correlation analysis between the Total Organic Carbon (TOC) content and various geochemical proxies in the Mbr1 mud shales suggests that OM enrichment in the study area was primarily controlled by the climate and sedimentation rate; substantial OM accumulation occurred only with abundant terrigenous OM input and a relatively high sedimentation rate. Redox conditions, primarily productivity, and terrigenous detrital input acted as secondary factors, collectively modulating OM enrichment. Event-driven transgressions also played an important role in creating conditions favorable for OM preservation. Synthesizing the influence of these multiple factors on OM enrichment, this study proposes two distinct composite models for OM enrichment, dominated by climate and sedimentation rate. Full article
(This article belongs to the Special Issue Element Enrichment and Gas Accumulation in Black Rock Series)
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25 pages, 3220 KB  
Article
Industrial-Based Comprehension on the Ceramic Body Composition by Continuous/Batch Grinding Methods
by Emrah Durgut
Minerals 2025, 15(10), 1070; https://doi.org/10.3390/min15101070 - 12 Oct 2025
Viewed by 313
Abstract
In this study, the effects of batch and continuous grinding on the ceramic floor tile body were investigated in terms of cost, capacity, and technical aspects. In batch milling, a changing speed during grinding was more efficient than a constant speed. Capacity and [...] Read more.
In this study, the effects of batch and continuous grinding on the ceramic floor tile body were investigated in terms of cost, capacity, and technical aspects. In batch milling, a changing speed during grinding was more efficient than a constant speed. Capacity and energy consumption increased as the mill rotation speed increased in continuous grinding. Specific energy consumptions were measured as 36 kW/ton and 43.1 kW/ton, with 1.6 ton/h and 8.375 t/h capacities. Additionally, d10, d50, and d90 values for ground ceramic floor tile bodies were determined to be 2.5, 9.5, and 47.2 µm and 2.5, 9.4, and 48.1 µm for batch and continuous grinding, respectively. No significant difference was observed in the color and shrinkage values, while water absorptions were calculated to be 1.1% and 0.3% as sintering properties for batch and continuous methods, respectively. In the phase analysis of a sintered body prepared using the continuous method, mullite and quartz were observed, while microcline was also analyzed differently from such minerals for the batch one. Structural changes, surface morphology, and roughness were also interpreted by DTA/TG, SEM, and AFM analysis. The presence of plastic clay minerals during the grinding process in batch milling caused non-plastic raw materials not to be ground sufficiently, and sintering characteristics changed. Full article
(This article belongs to the Special Issue From Clay Minerals to Ceramics: Progress and Challenges)
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17 pages, 91562 KB  
Article
Mineralogy and Critical Metal Distribution in Upper Carboniferous Aluminum-Bearing Strata from the Yangquan Mining Area, Northeastern Qinshui Basin: Insights from TIMA
by Ning Wang, Yingxia Xu, Jun Zhao, Shangqing Zhang, Zhiyi Liu and Menghuai Hou
Minerals 2025, 15(10), 1069; https://doi.org/10.3390/min15101069 - 12 Oct 2025
Viewed by 205
Abstract
Critical metals associated with aluminum-bearing strata have garnered increasing attention due to their considerable economic potential. Recent investigations have identified notable enrichment of Li, Ga, Zr, Nb, REEs (rare earth elements), etc., within the Upper Carboniferous Benxi Formation in the Yangquan mining area, [...] Read more.
Critical metals associated with aluminum-bearing strata have garnered increasing attention due to their considerable economic potential. Recent investigations have identified notable enrichment of Li, Ga, Zr, Nb, REEs (rare earth elements), etc., within the Upper Carboniferous Benxi Formation in the Yangquan mining area, the Northeastern Qinshui Basin, Northern China. However, their mineralogical characteristics and micro-scale modes of occurrence remain insufficiently constrained. In this study, we employed the TESCAN Integrated Mineral Analyzer (TIMA) in combination with X-ray diffraction (XRD) and clay-separation experiments to provide direct mineralogical evidence for the occurrence of Ti, Li, Ga, Zr, and REEs in claystone and aluminous claystone from the Benxi Formation, Yangquan mining area, Northeastern Qinshui Basin. Our results indicate that both lithologies are primarily composed of kaolinite and diaspore, with minor amounts of anatase and cookeite; illite is additionally present in the claystone. Titanium predominantly occurs as anatase in both lithologies, though a portion in aluminous claystone may be incorporated into kaolinite and other Ti-bearing minerals such as rutile and leucoxene. Lithium is primarily hosted by cookeite in both rock types. Mineral assemblage variations further suggest that kaolinite may have partially transformed into Li-rich chlorite (i.e., cookeite) during the transformation from aluminous claystone to claystone. Gallium is chiefly associated with diaspore and kaolinite, with a stronger correlation with diaspore in the aluminous claystone. Zircon is the sole carrier of Zr in both lithologies. Importantly, La and Ce show a consistent spatial association with O–Al–Si–Ti–P mixed aggregates in TIMA maps, particularly in aluminous claystone. Based on these spatial patterns, textural relationships, and comparisons with previous studies, phosphate minerals are inferred to be the dominant REE hosts, although minor contributions from other phases cannot be completely excluded. These findings highlight a previously underexplored mode of critical-metal enrichment in Northern Chinese bauxite-bearing strata and provide a mineralogical basis for future extraction and utilization. Full article
(This article belongs to the Special Issue Bauxite: Mineralogy, Geochemistry and Potential Industrial Application)
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19 pages, 3575 KB  
Article
Attenuation of Acid Mine Drainage in a Coal Waste Deposit in Southern Brazil and the Prospect of Transitioning from Active to Passive Treatment
by Felipe Santin Keller, Cláudio Boff, Daniela Silva, Alexandre Grigorieff, Cristiano Corrêa Weber, Jéssica Weiler and Ivo André Homrich Schneider
Minerals 2025, 15(10), 1068; https://doi.org/10.3390/min15101068 - 11 Oct 2025
Viewed by 272
Abstract
Capão da Roça, located in the municipality of Charqueadas, is one of the few areas of coal tailing deposits at the surface within the State of Rio Grande do Sul, Brazil that generates acid mine drainage (AMD). Over the course of 2007, the [...] Read more.
Capão da Roça, located in the municipality of Charqueadas, is one of the few areas of coal tailing deposits at the surface within the State of Rio Grande do Sul, Brazil that generates acid mine drainage (AMD). Over the course of 2007, the landfill was characterised in detail, and an active treatment plant involving pH neutralisation and metal precipitation operations was implemented to meet emission standards for mine water. In that year, based on the sulphur mass balance, it was estimated that the process of AMD generation would last for approximately two decades. The objective of this work was to study the temporal evolution of the parameters of the raw AMD. The effluent was analysed for 17 years on a monthly basis in regard to pH, acidity, metals (Fe, Al, and Mn), and sulphates. The results indicated an increase in pH (from 2.1 to 4.7), a decay in the concentration of metals (from 177.8 to 0.1 mg L−1 for iron, 29.0 to 0.1 mg L−1 for aluminium, and 3.1 to 0.6 mg L−1 for manganese), sulphates (from 2023 to 307 mg L−1), and acidity (from 539.5 mg CaCO3 L−1 to 3.96 mg CaCO3 L−1), which were adjusted to a first-order kinetic model in agreement with observations at some other mining sites. Over the years, the active lime neutralisation–precipitation treatment system has been efficient in treating the effluent. Today, most water quality parameters already meet emissions standards; however, the AMD treatment plant is still necessary to prevent pH fluctuations and to reduce the concentrations of manganese. For this reason, a transition from an active to a passive treatment system was considered. Pilot scale studies confirmed that channels filled with gravel-size limestone or slag enable the neutralisation/increase in the pH of the effluent and remove residual amounts of some metals, resulting in an effluent with no level of toxicity to the microcrustacean Daphnia magna. Full article
(This article belongs to the Section Environmental Mineralogy and Biogeochemistry)
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25 pages, 15886 KB  
Review
Coal-Based Direct Reduction for Dephosphorization of High-Phosphorus Iron Ore: A Critical Review
by Hongda Xu, Rui Li, Jue Kou, Xiaojin Wen, Jiawei Lin, Jiawen Yin, Chunbao Sun and Tichang Sun
Minerals 2025, 15(10), 1067; https://doi.org/10.3390/min15101067 - 11 Oct 2025
Viewed by 192
Abstract
Conventional separation methods often prove ineffective for complex, refractory high-phosphorus iron ores. Recent advances propose a coal-based direct reduction dephosphorization-magnetic separation process, achieving significant dephosphorization efficiency. This review systematically analyzes phosphorus occurrence states in high-phosphorus oolitic iron ores across global deposits, particularly within [...] Read more.
Conventional separation methods often prove ineffective for complex, refractory high-phosphorus iron ores. Recent advances propose a coal-based direct reduction dephosphorization-magnetic separation process, achieving significant dephosphorization efficiency. This review systematically analyzes phosphorus occurrence states in high-phosphorus oolitic iron ores across global deposits, particularly within iron minerals. We categorize contemporary research and elucidate dephosphorization mechanisms during coal-based direct reduction. Key factors influencing iron mineral phase transformation, iron enrichment, and phosphorus removal are comprehensively evaluated. Phosphorus primarily exists as apatite and collophane gangue m horization agents function by: (1) inhibiting phosphorus-bearing mineral reactions or binding phosphorus into soluble salts to prevent incorporation into metallic iron; (2) enhancing iron oxide reduction and coal gasification; (3) disrupting oolitic structures, promoting metallic iron particle growth, and improving the intergrowth relationship between metallic iron and gangue. Iron mineral phase transformations follow the sequence: Fe2O3 → Fe3O4 → FeO (FeAl2O4, Fe2SiO4) → Fe. Critical parameters for effective dephosphorization under non-reductive phosphorus conditions include reduction temperature, duration, reductant/dephosphorization agent types/dosages. Future research should focus on: (1) investigating phosphorus forms in iron minerals for targeted ore utilization; (2) reducing dephosphorization agent consumption and developing sustainable alternatives; (3) refining models for metallic iron growth and improving energy efficiency; (4) optimizing reduction atmosphere control; (5) implementing low-carbon emission strategies. Full article
(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
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25 pages, 4831 KB  
Article
Comparative Evaluation of Flow Rate Distribution Methods for Uranium In-Situ Leaching via Reactive Transport Modeling
by Maksat Kurmanseiit, Nurlan Shayakhmetov, Daniar Aizhulov, Aray Tleuberdy, Banu Abdullayeva and Madina Tungatarova
Minerals 2025, 15(10), 1066; https://doi.org/10.3390/min15101066 - 11 Oct 2025
Viewed by 158
Abstract
In situ leaching represents an efficient and safe method for uranium mining, where a suboptimal well flow rate distribution leads to solution imbalances between wells, forming stagnant zones that increase operational costs. This study examines a real technological block from the Budenovskoye deposit, [...] Read more.
In situ leaching represents an efficient and safe method for uranium mining, where a suboptimal well flow rate distribution leads to solution imbalances between wells, forming stagnant zones that increase operational costs. This study examines a real technological block from the Budenovskoye deposit, applying reactive transport modeling to optimize well flow rates and reduce operational time and reagent consumption. A reactive transport model was developed based on mass conservation and Darcy’s laws coupled with chemical kinetics describing sulfuric acid interactions with uranium minerals (UO2 and UO3). The model simulated a technological block with 4 production and 18 injection wells arranged in hexagonal cells over 511–542 days to achieve 90% uranium recovery. Six approaches for well flow rate redistribution were compared, based on different weighting factor calculation methods: advanced traditional, linear distance, squared distance, quadrilateral area, and two streamline-based approaches utilizing the minimum and average time of flight. The squared distance method achieved the highest efficiency, reducing operational costs by 5.7% through improved flow redistribution. The streamline-based methods performed comparably and offer potential advantages for heterogeneous conditions by automatically identifying hydraulic connections. The reactive transport modeling approach successfully demonstrated that multi-criteria optimization methods can improve ISL efficiency by 3.9%–5.7% while reducing operational costs. Full article
(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
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18 pages, 5594 KB  
Article
Optimization of High-Pressure Grinding Roll (HPGR) Performance in an Industrial-Scale HPGR/Tower Mill Comminution Circuit
by Bo Wei, Zhitao Yuan, Quan Feng, Qiang Zhang, Xinyang Xu, Qingyou Meng, Bern Klein and Lixia Li
Minerals 2025, 15(10), 1065; https://doi.org/10.3390/min15101065 - 11 Oct 2025
Viewed by 384
Abstract
The integration of high-pressure grinding roller (HPGR) with pre-concentration techniques and stirred mills is recognized for its energy efficiency. Studies have suggested that the feed with a P80 around 1 mm is acceptable for stirred mills or coarse particle flotation. Nonetheless, published [...] Read more.
The integration of high-pressure grinding roller (HPGR) with pre-concentration techniques and stirred mills is recognized for its energy efficiency. Studies have suggested that the feed with a P80 around 1 mm is acceptable for stirred mills or coarse particle flotation. Nonetheless, published experimental data characterizing the comminution behavior of single-stage HPGR circuits configured with a 1 mm screen aperture remain scarce. Moreover, extant research remains confined to laboratory scale. Consequently, critical performance metrics, including production capacity, screening efficiency, and process continuity, have not been substantively documented in the literature. In this paper, the HPGR performance in an industrial-scale HPGR/tower mill comminution circuit was assessed and optimized by laboratory and industrial tests. The research meticulously analyzed the impact of feed rate on the industrial-scale flip-flow screen and HPGR performance and found that the HPGR featuring two studded rolls with a diameter of 800 mm and a width of 400 mm, operating in a reverse classification circuit with a scalped feed by a 14.64 m2 flip-flow screen while running continuously 24 h per day, is capable of producing a −1 mm comminution product suitable for tower mill feed. Under the optimal operating conditions identified, it achieved a specific energy consumption of 4.57 kWh/t with a feed rate of 27.08 t/h. Full article
(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
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16 pages, 3467 KB  
Article
Coordination-Driven Rare Earth Fractionation in Kuliokite-(Y), (Y,HREE)4Al(SiO4)2(OH)2F5: A Crystal–Chemical Study
by Sergey V. Krivovichev, Victor N. Yakovenchuk, Olga F. Goychuk and Yakov A. Pakhomovsky
Minerals 2025, 15(10), 1064; https://doi.org/10.3390/min15101064 - 10 Oct 2025
Viewed by 153
Abstract
The crystal structure of kuliokite-(Y), Y4Al(SiO4)2(OH)2F5, has been re-investigated using the material from the type locality the Ploskaya Mt, Kola peninsula, Russian Arctic. It has been shown that in contrast to previous studies, [...] Read more.
The crystal structure of kuliokite-(Y), Y4Al(SiO4)2(OH)2F5, has been re-investigated using the material from the type locality the Ploskaya Mt, Kola peninsula, Russian Arctic. It has been shown that in contrast to previous studies, the mineral is monoclinic, Im, with a = 4.3213(1), b = 14.8123(6), c = 8.6857(3) Å, β = 102.872(4)°, and V = 541.99(3) Å3. The crystal structure was solved and refined to R1 = 0.030 on the basis of 3202 unique observed reflections. The average chemical composition determined by electron microprobe analysis is (Y2.96Yb0.49Er0.27Dy0.13Tm0.07Lu0.05Ho0.05Gd0.01Ca0.01)Σ4.04Al0.92Si2.04O8-[(OH)2.61F4.42]Σ7.03; the idealized formula is (Y,Yb,Er)4Al[SiO4]2(OH)2.5F4.5. The crystal structure of kuliokite-(Y) contains two symmetrically independent Y sites, Y1 and Y2, coordinated by eight and seven X anions, respectively (X = O, F). The coordination polyhedra can be described as a distorted square antiprism and a distorted pentagonal bipyramid, respectively. The refinement of site occupancies indicated that the mineral represents a rare case of HREE fractionation among two cation sites driven by their coordination numbers and geometry. In agreement with the lanthanide contraction, HREEs are selectively incorporated into the Y2 site with a smaller coordination number and tighter coordination environment. The strongest building unit of the structure is the [AlX2(SiO4)2] chain of corner-sharing AlX6 octahedra and SiO4 tetrahedra running along the a axis. The chains have their planes oriented parallel to (001). The Y atoms are located in between the chains, along with the F− and (OH)− anions, providing the three-dimensional integrity of the crystal structure. Each F− anion is coordinated by three Y3+ cations to form planar (FY3)8+ triangles parallel to the (010) plane. The triangles share common edges to form [F2Y2]4+ chains parallel to the a axis. The analysis of second-neighbor coordination of Y sites allowed us to identify the structural topology of kuliokite-(Y) as the only case of the skd network in inorganic compounds, previously known in molecular structures only. The variety of anionic content in the mineral allows us to identify the potential existence of two other mineral species that can tentatively be named ‘fluorokuliokite-(Y)’ and ‘hydroxykuliokite-(Y)’. Full article
(This article belongs to the Section Crystallography and Physical Chemistry of Minerals & Nanominerals)
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13 pages, 2455 KB  
Article
Spatial Distribution of Uranium and Thorium in the Soils of North Macedonia
by Trajče Stafilov and Robert Šajn
Minerals 2025, 15(10), 1063; https://doi.org/10.3390/min15101063 - 9 Oct 2025
Viewed by 331
Abstract
The aim of the study was to determine the spatial distribution and assess uranium and thorium contamination in the soils of North Macedonia. Topsoil samples (0–30 cm) were collected from 995 locations across the country on a 5 × 5 km grid. The [...] Read more.
The aim of the study was to determine the spatial distribution and assess uranium and thorium contamination in the soils of North Macedonia. Topsoil samples (0–30 cm) were collected from 995 locations across the country on a 5 × 5 km grid. The soil samples were analysed by inductively coupled plasma–mass spectrometry (ICP-MS) using the total digestion method. The distribution of uranium and thorium in the soils is discussed according to the country’s 8 statistical regions, 15 major geological formations and 13 pedological units. The average uranium content is 2.1 mg/kg, ranging from <0.1 to 13 mg/kg (median 2.0 mg/kg), while the average thorium content is 9.3 mg/kg, ranging from 0.20 to 92 mg/kg (median 9.5 mg/kg). The spatial distribution patterns of U and Th in the soils of North Macedonia are very similar and are determined by geology (parent material and mineralisation). High uranium (2.9–13 mg/kg) and thorium (42–92 mg/kg) contents were found mainly in soils in the areas of Neogene and Palaeozoic igneous rocks and Neogene clastites (Pelagonian, East Macedonian zone), as well as in the Kratovo-Zletovo Massif in the north-eastern part of the country and in the Kožuf Mountains in the central and southern parts, where Neogene igneous rocks predominate. According to the pedological units, the hydromorphic soils (mean content of 2.9 mg/kg U and 12 mg/kg Th) in the valleys of the country’s main rivers, which predominate in the western part, were the richest for these elements. Full article
(This article belongs to the Special Issue Mineralogical and Geochemical Characterization of Geological Materials, 2nd Edition)
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16 pages, 4007 KB  
Article
Influence of Humic Acid on the Swelling Inhibition of Clay Minerals and Process Optimization
by Ying Cheng, Dandan Zhang, Xing Gao, Junxia Yu, Ruan Chi, Bona Deng and Fang Zhou
Minerals 2025, 15(10), 1062; https://doi.org/10.3390/min15101062 - 9 Oct 2025
Viewed by 235
Abstract
Medium and heavy rare earths (REEs) are mainly from weathered crust elution-deposited rare earth ores (WREOs), where REEs are adsorbed in ionic form on the surface of clay minerals such as kaolinite, illite, halloysite, etc. REEs in WREOs are extracted through the in [...] Read more.
Medium and heavy rare earths (REEs) are mainly from weathered crust elution-deposited rare earth ores (WREOs), where REEs are adsorbed in ionic form on the surface of clay minerals such as kaolinite, illite, halloysite, etc. REEs in WREOs are extracted through the in situ leaching process with (NH4)2SO4 solution via ion exchange. However, this process often results in the swelling of clay minerals, subsequently destroying the ore body structure and causing landslides. This study investigated the inhibitory effects of humic acid (HA) on the swelling of primary clay minerals. An optimal inhibition on the swelling of clay minerals was demonstrated at 0.2 g/L. HA was mixed with 0.1 mol/L (NH4)2SO4 solution at the solution pH of 6.8 and temperature of 25 °C. The swelling efficiency of kaolinite, illite, and halloysite in presence of HA decreased by 0.29%, 1.19%, and 0.19%, respectively, compared to using (NH4)2SO4 alone. The surface hydration parameter of clay minerals was further calculated through viscosity theory. It was demonstrated that the surface hydration parameter of kaolinite and halloysite decreased nearly threefold, while that of illite decreased fivefold, demonstrating a desirable inhibition on clay swelling with HA. Viscosity theory offers valuable theoretical support for the development of anti-swelling agents. Full article
(This article belongs to the Special Issue Recent Progress in the Processing of Rare-Earth Ore)
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33 pages, 77489 KB  
Article
Chemistry and Fe Isotopes of Magnetites in the Orbicular Bodies in the Tanling Diorite and Implications for the Skarn Iron Mineralization in the North China Craton
by Ruipeng Li, Shangguo Su and Peng Wang
Minerals 2025, 15(10), 1061; https://doi.org/10.3390/min15101061 - 9 Oct 2025
Viewed by 193
Abstract
Skarn-type iron ore is economically significant, and numerous skarn ore deposits have been identified in the North China Craton. The newly discovered orbicular diorite in this region is distinguished from other analogous rocks due to the accumulation of large magnetite particles, which may [...] Read more.
Skarn-type iron ore is economically significant, and numerous skarn ore deposits have been identified in the North China Craton. The newly discovered orbicular diorite in this region is distinguished from other analogous rocks due to the accumulation of large magnetite particles, which may shed new light on the genesis of this ore type. The magnetite in different parts of the orbicular structure exhibits distinct compositional differences. For example, magnetite at the edge has a small particle size (200 μm) and is associated with the minerals plagioclase and hornblende, indicating that it crystallized from normal diorite magma. By contrast, magnetite in the core has a relatively large particle size (>1000 μm), is associated with apatite and actinolite, and contains apatite inclusions as well as numerous pores. The size of magnetite in the mantle falls between that of the edge and the core. The syngenetic minerals of magnetite in the mantle include epidote and plagioclase. The magnetites in the cores of orbicules have a higher content of Ti, Al, Ni, Cr, Sc, Zn, Co, Ga, and Nb than those in the rim. The δ56Fe value of the core magnetite (0.46‰–0.78‰) is much higher than that of the mantle and rim magnetite in orbicules. Moreover, the δ56Fe value of magnetite increases as the V content of magnetite gradually decreases. This large iron isotope fractionation is likely driven by liquid immiscibility that forms iron-rich melts under high oxygen fugacity. The reaction between magma and carbonate xenoliths (Ca, Mg)CO3 during magma migration generates abundant CO2, which significantly increases the oxygen fugacity of the magmatic system. Under the action of CO2 and other volatile components, liquid immiscibility occurs in the magma chamber, and Fe-rich oxide melts are formed by the melting of carbonate xenoliths. Iron oxides (Fe3O4/Fe2O3) will crystallize close to the liquidus due to high oxygen fugacity. These characteristics of magnetite in the Tanling orbicular diorite (Wuan, China) indicate that diorite magma reacts with carbonate xenoliths to form “Fe-rich melts”, and skarn iron deposits are probably formed by the reaction of intermediate-basic magma with carbonate rocks that generate such “Fe-rich melts”. A possible reaction is as follows: diorite magma + carbonate → (magnetite-actinolite-apatite) + garnet + epidote + feldspar + hornblende + CO2↑. Full article
(This article belongs to the Special Issue Using Mineral Chemistry to Characterize Ore-Forming Processes)
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21 pages, 11164 KB  
Article
Morphology and Chemical Composition of Newly Discovered Alluvial Gold from Baia, Eastern Carpathians, Romania
by Sergiu Drăguşanu and Călin Gabriel Tămaş
Minerals 2025, 15(10), 1060; https://doi.org/10.3390/min15101060 - 8 Oct 2025
Viewed by 382
Abstract
This study documents the first-ever recorded occurrence of alluvial gold in the foreland region of the Eastern Carpathians, specifically within the Moldavian Platform, Romania, and presents the morphological analysis and the chemical composition of the newly discovered alluvial gold. A total of 115 [...] Read more.
This study documents the first-ever recorded occurrence of alluvial gold in the foreland region of the Eastern Carpathians, specifically within the Moldavian Platform, Romania, and presents the morphological analysis and the chemical composition of the newly discovered alluvial gold. A total of 115 gold particles, with a combined weight of approximately 0.50 g, were collected from three distinct sites within the Baia region, near Falticeni town. The native gold grains exhibit average length and width ranging from 3.93 mm to 2.50 mm in location #1, 0.43 mm to 0.30 mm in location #2, and 1.01 mm to 0.56 mm in location #3, respectively. The gold grains are rounded to sub-rounded and display discoidal to subdiscoidal shapes. Traces of the original quartz gangue are occasionally retained on their surfaces. The morphological analysis and the presence of quartz attached to the gold grains suggest a short transportation distance. Quantitative electron probe microanalysis conducted on 16 gold grains yields a silver (Ag) content between 0.56 wt% to 6.19 wt%. The primary source of the alluvial gold remains unidentified. We suggest that this could be orogenic gold type deposit. Full article
(This article belongs to the Special Issue Native Gold as a Specific Indicator Mineral for Gold Deposits, 2nd Edition)
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15 pages, 6333 KB  
Article
Design of New Eco-Cementitious Material Based on Foundry Slag and Lime Sludge
by Camila Lopes Eckert, Lucio Rosso Neto, Carlos Henrique Borgert, Júlio Preve Machado, Felipe Fardin Grillo, José Roberto de Oliveira, Matheus Vinicius Gregory Zimmermann, Mateus Milanez, Tchesare Andreas Keller, Tiago Elias Allievi Frizon, Bernardo Araldi da Silva, Agenor De Noni Junior and Eduardo Junca
Minerals 2025, 15(10), 1059; https://doi.org/10.3390/min15101059 - 8 Oct 2025
Viewed by 261
Abstract
Foundry slag has different characteristics from blast furnace slag, such as its high SiO2 content and low basicity (CaO/SiO2 < 1), which prevent it from being used as a cementitious component. Lime slurry is a waste product with a high CaO [...] Read more.
Foundry slag has different characteristics from blast furnace slag, such as its high SiO2 content and low basicity (CaO/SiO2 < 1), which prevent it from being used as a cementitious component. Lime slurry is a waste product with a high CaO content and can be used to increase the basicity of the mixture. The aim of this study is to obtain new supplementary, eco-cementitious material composed of foundry slag and lime sludge. The compositions were designed with binary basicity (molar ratio of CaO/SiO2) ranging from 1.0 to 1.4. Clinker was replaced with the proposed material in the range of 6–34 wt% and the performance of the different cement compositions was tested. The results showed that replacing 20 wt% of clinker with the new eco-cementitious material with binary basicity of 1.2 resulted in cement with the same mechanical strength as the reference cement. The new material reacted with free CaO to generate additional calcium silicate hydrate. The initial setting time of the cement containing the new eco-cementitious material was 240 min, acting as hydration reaction retardant. The technical feature of the new eco-cementitious material allows the use of both wastes in cement composition, contributing to the requirements of circular economy. Full article
(This article belongs to the Special Issue Characterization and Reuse of Slag)
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