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Minerals, Volume 14, Issue 7 (July 2024) – 103 articles

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21 pages, 15719 KiB  
Article
Lithium-Rich Deposits in the Liangshan Formation during the Permian in the Upper Yangtze Plate, China
by Yin Gong, Chun-Yao Liu, Yin Liu, Li Lei, Meng Xiang, Bo Yang, Zhou Zhou, Yang Zhang, Xiang-Rong Yang, Lei Yan and Yuan Xiong
Minerals 2024, 14(7), 735; https://doi.org/10.3390/min14070735 - 22 Jul 2024
Viewed by 266
Abstract
With the increasing demand for lithium (Li) resources in industry, there has been new attention on clay-type lithium-rich deposits recently. In this study, a Li-rich clay deposit with a Li2O content up to 0.3% in the Liangshan Formation in the upper [...] Read more.
With the increasing demand for lithium (Li) resources in industry, there has been new attention on clay-type lithium-rich deposits recently. In this study, a Li-rich clay deposit with a Li2O content up to 0.3% in the Liangshan Formation in the upper Yangtze, South China Block was demonstrated. We analysed the mineralogy and element geochemistry of the samples from the Liangshan Formation and its underlying and overlying layers. Kaolinite (average 53%, up to 93%) was the major mineral in the samples from the Liangshan Formation. The Li concentrations increased with increasing kaolinite compositions and Al2O3 concentrations. Furthermore, based on the geochemical indicators, it was suggested that the clay formation and Li enrichment were related to the weathering processes of the bottom impure limestone under the hot and wet climate, and the sedimentary processes in the anoxic, still, and flat land–sea interaction area in the Upper Yangtze. The Li was probably sourced from the bottom impure limestone during the weathering stage. The samples from the Liangshan Formation also showed REE enrichment from 117 to 729 μg/g. Full article
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27 pages, 380 KiB  
Review
Recent Uses of Ionic Liquids in the Recovery and Utilization of Rare Earth Elements
by Francisco Jose Alguacil, Jose Ignacio Robla and Olga Rodriguez Largo
Minerals 2024, 14(7), 734; https://doi.org/10.3390/min14070734 - 22 Jul 2024
Viewed by 268
Abstract
The importance of rare earth elements as a basis for the development of new technologies or the improvement of existing ones makes their recovery from raw and waste materials necessary. In this recovery, hydrometallurgy and its derivative solvometallurgy play key roles due to [...] Read more.
The importance of rare earth elements as a basis for the development of new technologies or the improvement of existing ones makes their recovery from raw and waste materials necessary. In this recovery, hydrometallurgy and its derivative solvometallurgy play key roles due to their operational characteristics, which are emphasized with the use of ionic liquids. This manuscript reviews the most recent advances (2023 and 2024) in the use of ionic liquids in unit operations (leaching and separation technologies) aimed at the recovery of these valuable and strategic metals. Moreover, a comprehensive review is presented of the use of these chemicals in the development of advanced materials containing some of these rare earth elements. Full article
21 pages, 6293 KiB  
Article
The Formation Age and Magma Source of the Xiaonanshan–Tunaobao Cu-Ni-PGE Deposit in the Northern Margin of the North China Craton
by Guanlin Bai, Jiangang Jiao, Xiaotong Zheng, Yunfei Ma and Chao Gao
Minerals 2024, 14(7), 733; https://doi.org/10.3390/min14070733 - 22 Jul 2024
Viewed by 269
Abstract
The Xiaonanshan–Tunaobao Cu-Ni-PGE deposit is located in the northern margin of the North China Craton (N-NCC) in central Inner Mongolia. However, the age, magma source, petrogenesis, and sulfide mineralization mechanism of the ore-related Xiaonanshan-Tunaobao pluton remain unclear. Zircon U-Pb dating indicates the Tunaobao [...] Read more.
The Xiaonanshan–Tunaobao Cu-Ni-PGE deposit is located in the northern margin of the North China Craton (N-NCC) in central Inner Mongolia. However, the age, magma source, petrogenesis, and sulfide mineralization mechanism of the ore-related Xiaonanshan-Tunaobao pluton remain unclear. Zircon U-Pb dating indicates the Tunaobao pluton formed at 275.9 ± 2.8 Ma (Early Permian), similar to the Xiaonanshan pluton (272.7 ± 2.9 Ma). The ore-related gabbro is enriched in LREE and LILE (e.g., Rb) and depleted in HREE and HFSE (e.g., Nb and Ti). It likely originated from enriched mantle metasomatized by subduction fluids, supported by enriched Hf-Nd isotopes (–34.34 to –6.16 for zircon εHf(t) and –7.24 to –5.92 for whole-rock εNd(t) values) and high Ba/La but low Rb/Y ratios. The δ34S values of the Xiaonanshan sulfides range from 4.5‰ to 11.4‰, indicating a mantle origin with contribution from surrounding rocks. Combining previous recognition with this study, we propose that the Xiaonanshan–Tunaobao pluton formed in a post-collision extensional setting. Full article
(This article belongs to the Special Issue Mineral Resources in North China Craton)
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16 pages, 1241 KiB  
Article
Açaí Seed Biochar-Based Phosphate Fertilizers for Improving Soil Fertility and Mitigating Arsenic-Related Impacts from Gold Mining Tailings: Synthesis, Characterization, and Lettuce Growth Assessment
by Yan Nunes Dias, Wendel Valter da Silveira Pereira, Cecílio Frois Caldeira, Sílvio Junio Ramos, Edna Santos de Souza, Paula Godinho Ribeiro and Antonio Rodrigues Fernandes
Minerals 2024, 14(7), 732; https://doi.org/10.3390/min14070732 - 22 Jul 2024
Viewed by 196
Abstract
Biochar represents a promising alternative for enhancing substrates and remediating contaminants in mining areas. Given that arsenic (As) and phosphorus (P) share similar chemical forms, the combination of biochar and P fertilizers may reduce As uptake, thereby mitigating As-related impacts. This study aimed [...] Read more.
Biochar represents a promising alternative for enhancing substrates and remediating contaminants in mining areas. Given that arsenic (As) and phosphorus (P) share similar chemical forms, the combination of biochar and P fertilizers may reduce As uptake, thereby mitigating As-related impacts. This study aimed to evaluate the potential of biochar-based P fertilizers in improving soil fertility and mitigating human health risks from gold mining tailings in the eastern Brazilian Amazon. Biochar from açaí palm (Euterpe oleracea Mart.) seeds was produced through enrichment with single and triple superphosphate at a ratio of 1:4, at 400 °C, and applied to mining tailings at 0.5%, 1%, and 2%. After one year of incubation, lettuce plants were grown for 70 days. Biochar reduced As absorption by lettuce and improved biomass and nutrient accumulation, resulting in improved vegetation indices. Biochar was effective in reducing non-carcinogenic As risks via ingestion of soil and plants to acceptable levels. Regression equations explained the As absorption behavior as affected by the biochar and the importance of biochar-related nutrients in reducing As stress. This study demonstrates the potential of P-enriched biochar as an amendment for As-contaminated soils, reducing As absorption, increasing P availability, and improving plant growth. Full article
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41 pages, 35191 KiB  
Review
Laser-Induced Breakdown Spectroscopy in Mineral Exploration and Ore Processing
by Russell S. Harmon
Minerals 2024, 14(7), 731; https://doi.org/10.3390/min14070731 - 22 Jul 2024
Viewed by 305
Abstract
Laser-induced breakdown spectroscopy (LIBS) is a type of optical emission spectroscopy capable of rapid, simultaneous multi-element analysis. LIBS is effective for the analysis of atmospheric gases, geological fluids, and a broad spectrum of minerals, rocks, sediments, and soils both in and outside the [...] Read more.
Laser-induced breakdown spectroscopy (LIBS) is a type of optical emission spectroscopy capable of rapid, simultaneous multi-element analysis. LIBS is effective for the analysis of atmospheric gases, geological fluids, and a broad spectrum of minerals, rocks, sediments, and soils both in and outside the traditional laboratory setting. With the recent introduction of commercial laboratory systems and handheld analyzers for use outside the laboratory for real-time in situ analysis in the field, LIBS is finding increasing application across the geosciences. This article first overviews the LIBS technique and then reviews its application in the domain of mineral exploration and ore processing, where LIBS offers some unique capabilities. Full article
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14 pages, 6797 KiB  
Article
Telluride Mineralogy of the Kochbulak Epithermal Gold Deposit, Tien Shan, Eastern Uzbekistan
by Yongwei Lu, Xiaobo Zhao, Chunji Xue, Bakhtiar Nurtaev, Yiwei Shi, Yangtao Liu and Shukhrat Shukurov
Minerals 2024, 14(7), 730; https://doi.org/10.3390/min14070730 - 22 Jul 2024
Viewed by 181
Abstract
The Kochbulak gold deposit is situated on the northern slope of the Kurama range of eastern Uzbekistan and is one of the largest Tellurium-rich epithermal gold deposits in the world. Based on a detailed field and petrological investigation, three stages of mineralization can [...] Read more.
The Kochbulak gold deposit is situated on the northern slope of the Kurama range of eastern Uzbekistan and is one of the largest Tellurium-rich epithermal gold deposits in the world. Based on a detailed field and petrological investigation, three stages of mineralization can be classified, including, from early to late, quartz–pyrite vein stage, quartz–telluride–sulfide–sulphosalt–native gold stage, and pyrite–chalcopyrite vein stage. Abundant tellurides, including tellurobismuthite, rucklidgeite, tetradymite, altaite, volynskite, and hessite, have been well recognized in the second (main) mineralization stage. Based on the mineral assemblages and petrogenetic occurrence, the sequence of tellurides in the second mineralization stage can be approximately identified as altaite+calaverite+native tellurium, calaverite+native gold, Bi-telluride (e.g., tellurobismuthite and rucklidgeite)+petzite+native gold, Ag-Bi telluride (e.g., volynskite), and Ag-telluride (e.g., hessite)+native gold. By depicting the Log ƒ(Te2)-Log ƒ(S2) relationship diagram of the Kochbulak gold deposit under 250 °C and 200 °C, the Log ƒ(S2) value ranges from −14.7 to −8.6 and from −16.7 to −10.9, respectively, with Log ƒ(Te2) value varies from −12.3 to −7.8 under 250 °C and ranges from −13.8 to −11.2 under 200 °C. Full article
(This article belongs to the Special Issue Selenium, Tellurium and Precious Metal Mineralogy)
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12 pages, 5585 KiB  
Article
FIB-SEM Study of Archaeological Human Petrous Bones: 3D Structures and Diagenesis
by Jamal Ibrahim, Eugenia Mintz, Lior Regev, Dalit Regev, Ilan Gronau, Steve Weiner and Elisabetta Boaretto
Minerals 2024, 14(7), 729; https://doi.org/10.3390/min14070729 - 21 Jul 2024
Viewed by 260
Abstract
The petrous bone generally preserves ancient DNA better than other fossil bones. One reason for this is that the inner layer of the petrous bone of pigs and humans contains about three times as many osteocytes as other bones, and hence more DNA. [...] Read more.
The petrous bone generally preserves ancient DNA better than other fossil bones. One reason for this is that the inner layer of the petrous bone of pigs and humans contains about three times as many osteocytes as other bones, and hence more DNA. A FIB-SEM study of modern pig petrous bones showed that the 3D structure of the thin inner layer is typical of woven bone that forms in the fetus, whereas the thicker outer layer has a lamellar structure. The lamellar structure is common in mammalian bones. Here we study human petrous bones that are about 2500 years old, obtained from three Phoenician sites in Sicily, Italy. A detailed FIB-SEM study of two of these bones, one well preserved and the other poorly preserved, shows that the 3D bone type structure of the human petrous inner layer is woven bone, and the outer layer is lamellar bone. These are the same bone type structures found in pig petrous bones. Furthermore, by comparing nine differently preserved petrous bones from the same archaeological region and age, we show that their collagen contents vary widely, implying that organic material can be significantly altered during diagenesis. The mineral crystals are better preserved and hence less crystalline in the inner layers compared to the outer layers. We therefore infer that the best-preserved DNA in fossil petrous bones should be found in the thin inner layers immediately adjacent to the otic cavity where much more DNA is initially present and the mineral phase tends to be better preserved. Full article
(This article belongs to the Section Biomineralization and Biominerals)
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16 pages, 5131 KiB  
Article
Exploring the Effect of Particle Loading Density on Respirable Dust Classification by SEM-EDX
by Daniel Sweeney, Cigdem Keles and Emily Sarver
Minerals 2024, 14(7), 728; https://doi.org/10.3390/min14070728 - 20 Jul 2024
Viewed by 392
Abstract
Exposure to respirable coal mine dust (RCMD) still poses health risks to miners. Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) is a powerful tool for RCMD characterization because it provides particle-level data, including elemental ratios (via the EDX signals) that can enable [...] Read more.
Exposure to respirable coal mine dust (RCMD) still poses health risks to miners. Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) is a powerful tool for RCMD characterization because it provides particle-level data, including elemental ratios (via the EDX signals) that can enable classification by inferred mineralogy. However, if the particle loading density (PLD) is high on the analyzed substrate (filter sample), interference between neighboring particles could cause misclassification. To investigate this possibility, a two-part study was conducted. First, the effect of PLD on RCMD classification was isolated by comparing dust particles recovered from the same parent filters under both low- and high-PLD conditions, and a set of modified classification criteria were established to correct for high PLD. Second, the modified criteria were applied to RCMD particles on pairs of filters, with each pair having one filter that was analyzed directly (frequently high PLD) and another filter from which particles were recovered and redeposited prior to analysis (frequently lower PLD). It was expected that application of the modified criteria would improve the agreement between mineralogy distributions for paired filters; however, relatively little change was observed for most pairs. These results suggest that factors other than PLD, including particle agglomeration, can have a substantial effect on the particle EDX data collected during direct-on-filter analysis. Full article
(This article belongs to the Special Issue Size Distribution, Chemical Composition and Morphology of Mine Dust)
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19 pages, 12914 KiB  
Article
Preparation of High-Purity Quartz Sand by Vein Quartz Purification and Characteristics: A Case Study of Pakistan Vein Quartz
by Mei Xia, Xiaoyong Yang and Zhenhui Hou
Minerals 2024, 14(7), 727; https://doi.org/10.3390/min14070727 - 19 Jul 2024
Viewed by 367
Abstract
This study focuses on the purification and evaluation of the high-purity quartz (HPQ) potential of vein quartz ore from Pakistan. Vein quartz is grayish-white and translucent, with its mineral composition mainly comprising quartz crystal. Processed quartz sand is obtained from quartz raw ore [...] Read more.
This study focuses on the purification and evaluation of the high-purity quartz (HPQ) potential of vein quartz ore from Pakistan. Vein quartz is grayish-white and translucent, with its mineral composition mainly comprising quartz crystal. Processed quartz sand is obtained from quartz raw ore through purifying technologies, including crushing, ultrasonic desliming, flotation, high-temperature calcination, water quenching, hot pressure acid leaching, and chlorination roasting. The microscopic characteristics show that the vein quartz raw ore has a medium-coarse granular metacrystalline structure, high quartz content, with only a small quantity of fine-grained K-feldspar. The inclusions primarily consist of large-sized primary inclusions and secondary fluid inclusions developed along the micro-fractures, and the content of inclusions in most areas of the crystal is very low or even nonexistent. The quartz ore with such inclusion characteristics is considered a relatively good raw material for quartz. Component analysis shows that the main impurity elements in the quartz ore are Al, K, Ca, Na, Ti, Fe, and Li, with a total impurity element content of 128.86 µg·g−1. After purification, only lattice impurity elements Al, Ti, and Li remain in the processed quartz sand, resulting in a total impurity element content of 24.23 µg·g−1, an impurity removal rate of 81.20%, and the purity of SiO2 reaching 99.998 wt.%. It is suggested that when the quartz raw ore contains high content of lattice impurity elements, such as Al, Li, and Ti, it is difficult to remove them by the current purification method. In industrial production, considering the economic cost, if quartz sand still contains high content of lattice impurity elements Al, Ti, and Li after flotation, it cannot be used as a raw material for high-end HPQ. Full article
(This article belongs to the Special Issue Physicochemical Properties and Purification of Quartz Minerals)
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13 pages, 4358 KiB  
Article
Synthesis of Geopolymers Incorporating Mechanically Activated Fly Ash Blended with Alkaline Earth Carbonates: A Comparative Analysis
by Alexander M. Kalinkin, Elena V. Kalinkina, Ekaterina A. Kruglyak and Alla G. Ivanova
Minerals 2024, 14(7), 726; https://doi.org/10.3390/min14070726 - 19 Jul 2024
Viewed by 353
Abstract
The objective of this study is to perform a comparative analysis of the impact of incorporating alkaline earth metal carbonates (MCO3, where M–Mg, Ca, Sr, Ba) into low-calcium fly ash (FA) on the geopolymerization processes and the resultant properties of composite [...] Read more.
The objective of this study is to perform a comparative analysis of the impact of incorporating alkaline earth metal carbonates (MCO3, where M–Mg, Ca, Sr, Ba) into low-calcium fly ash (FA) on the geopolymerization processes and the resultant properties of composite geopolymers. Mechanical activation was employed to enhance the reactivity of the mixtures. The reactivity of the mechanically activated (FA + alkaline earth carbonate) blends towards NaOH solution was experimentally studied using XRD analysis and FTIR spectroscopy. In agreement with thermodynamic calculations, MgCO3 demonstrated the most active interaction with the alkaline solution, whereas strontium and barium carbonates exhibited little to no chemical interaction, and calcite was situated in the transition region. As the calcite content in the mixture with FA increased, the compressive strength of the geopolymers continuously improved. The addition of Mg, Sr, and Ba carbonates to the FA did not enhance the strength of geopolymers. However, the strength of geopolymers based on these blends was comparable with that of geopolymers based on 100% FA. The strength of geopolymers synthesized from the 100% FA and from the (90% FA + 10% MCO3) blends, mechanically activated for 180 s, at the age of 180 days was 11.0 MPa (0% carbonate), 11.1 MPa (10% MgCO3), 36.5 MPa (10% CaCO3), 13.6 MPa (10% SrCO3), and 12.4 MPa (10% BaCO3) MPa, respectively. The influence of carbonate additives on the properties of the composite geopolymers was examined, highlighting filler, dilution, and chemical effects. The latter determined the unique position of calcite among the carbonates of alkaline earth metals. Full article
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26 pages, 24038 KiB  
Article
Petrogenesis of the Early Jurassic–Early Cretaceous Adakite-like Rocks in the Erguna Block, NE China: Implications for the Tectonic Evolution of the Mongol–Okhotsk Ocean
by Yuanchao Wang, Yuanyi Zhao, Xinfang Shui and Zaili Tao
Minerals 2024, 14(7), 725; https://doi.org/10.3390/min14070725 - 19 Jul 2024
Viewed by 286
Abstract
The petrogenesis and geodynamic setting of the Mesozoic magmatic rocks in the Erguna Block, NE China remains controversial, especially the relationship between magmatism and the subduction history of the Mongol–Okhotsk oceanic plate. Here we present data for the Early Jurassic–Early Cretaceous adakite-like magmatic [...] Read more.
The petrogenesis and geodynamic setting of the Mesozoic magmatic rocks in the Erguna Block, NE China remains controversial, especially the relationship between magmatism and the subduction history of the Mongol–Okhotsk oceanic plate. Here we present data for the Early Jurassic–Early Cretaceous adakite-like magmatic rocks from Chaoman Farm in the northeastern part of the Erguna Block. Zircon U-Pb dating reveals that the syenogranites crystallized at around 190–180 Ma, while the monzonites, quartz diorite porphyries, and quartz monzonite porphyries were emplaced at around 147–143 Ma. The syenogranites, monzonites, quartz diorite porphyries, and quartz monzonite porphyries are adakite-like rocks. The syenogranites and quartz monzonite porphyries were produced by the partial melting of a thickened ancient mafic lower continental crust and a thickened juvenile lower crust, respectively. Meanwhile, the monzonites and quartz diorite porphyries were formed as a result of partial melting of the oceanic crust. In conclusion, the occurrence of these Early Jurassic magmatic rocks was closely linked to the process of southward subduction of the Mongol–Okhotsk oceanic plate. On the contrary, the Late Jurassic to early Early Cretaceous magmatism (147–143 Ma) occurred in an extensional environment, and was probably triggered by upwelling of the asthenosphere. Full article
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26 pages, 14806 KiB  
Article
Genesis of Fe-Ti-(V) Oxide-Rich Rocks by Open-System Evolution of Mafic Alkaline Magmas: The Case of the Ponte Nova Massif, SE Brazil
by Amanda Andrade de Souza, Rogério Guitarrari Azzone, Luanna Chmyz, Lina Maria Cetina Tarazona, Fábio Ramos Dias de Andrade, José Vinicius Martins, Excelso Ruberti and Celso de Barros Gomes
Minerals 2024, 14(7), 724; https://doi.org/10.3390/min14070724 - 19 Jul 2024
Viewed by 283
Abstract
The formation of Fe-Ti oxides-rich layers is commonly associated with open-system magma chamber dynamics. These processes are widely discussed due to the economic importance of Fe-Ti-(V) deposits, although an alkaline-system approach to the matter is still scarce. In this study, we use petrography, [...] Read more.
The formation of Fe-Ti oxides-rich layers is commonly associated with open-system magma chamber dynamics. These processes are widely discussed due to the economic importance of Fe-Ti-(V) deposits, although an alkaline-system approach to the matter is still scarce. In this study, we use petrography, mineral chemistry, X-ray diffraction and elemental geochemical analyses (whole-rock and Sr isotopes) to discuss the process associated with the formation of Fe-Ti-(V) oxide-rich clinopyroxenite (OCP, 7–15 vol.%) and magnetitite (MTT, 85 vol.%) from the Ponte Nova alkaline mafic–ultramafic massif (PN, K-Ar 87.6 Ma). Ilmenite and Ti-magnetite from both OCP and MTT exhibit higher MgO contents (MgO > 5.0 wt%) than other PN rocks. OCP shows high 87Sr/86Sri ratios, equivalent to crustal-contaminated lithotypes of the PN Central Intrusion, while MTTs are less radiogenic. The oxide supersaturation in silicate mafic magmas is typically associated with the dislocation of the liquid cotectic evolution line, shifting to Fe-Ti-(V) oxide minerals stability field, mainly Ti-magnetite. Different magmatic processes can lead to these changes such as crustal contamination and magma recharge. For the PN massif, the OCP was formed by the assimilation of crustal contaminants in a mush region, near the magma chamber upper walls, which was associated with the evolution of the main pulse. Differently, the MTT would have its origin related to the interaction between magma chamber evolved liquids and more primitive liquids during a new episode of magma recharge. Lastly, post-magmatic events were superimposed on these rocks, generating sulfides. Full article
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10 pages, 6264 KiB  
Article
Bismuth White (Bismuth Oxychloride) and Its Use in Portrait Miniatures Painted by George Engleheart
by Lucia Burgio
Minerals 2024, 14(7), 723; https://doi.org/10.3390/min14070723 - 19 Jul 2024
Viewed by 280
Abstract
This article documents the discovery of ‘bismuth white’ on three late eighteenth-century portrait miniatures in the Victoria and Albert Museum collections, painted by renowned English artist George Engleheart. Metallic bismuth and bismuth-containing minerals have been known for centuries and were used on various [...] Read more.
This article documents the discovery of ‘bismuth white’ on three late eighteenth-century portrait miniatures in the Victoria and Albert Museum collections, painted by renowned English artist George Engleheart. Metallic bismuth and bismuth-containing minerals have been known for centuries and were used on various types of artistic production, from German Wismutmalerei to medieval manuscripts and Renaissance paintings. However, until now they had never been documented on portrait miniatures, despite documentary evidence that suggests their use. The Raman analysis of the three miniatures shows that bismuth oxychloride (BiOCl, corresponding to the mineral bismoclite) is present, and XRF data prove that this material was used as a white pigment in its own right. This work is a pilot study: it represents the first step in the rediscovery of bismuth white as an artist’s pigment, and hopes to provide encouragement to other institutions to look deeper in their collections and map out the use of a relatively rare white material which until now had not been detected or documented in fine art objects. Full article
(This article belongs to the Special Issue Geomaterials and Cultural Heritage)
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21 pages, 33803 KiB  
Article
Clarification of Distinguishing Natural Super-Reduced Phase from Synthetics Based on Inclusions
by Yutong Ma, Mengqi Miao, Ming Chen and Shan Qin
Minerals 2024, 14(7), 722; https://doi.org/10.3390/min14070722 - 18 Jul 2024
Viewed by 273
Abstract
Super-reduced phases (SRPs), such as silicon carbide (SiC) and metal silicides, have increasingly been reported in various geological environments. However, their origin remains controversial. SRP inclusions (e.g., metal silicides and metallic silicon (Si0)) within SiC are commonly believed to indicate a [...] Read more.
Super-reduced phases (SRPs), such as silicon carbide (SiC) and metal silicides, have increasingly been reported in various geological environments. However, their origin remains controversial. SRP inclusions (e.g., metal silicides and metallic silicon (Si0)) within SiC are commonly believed to indicate a natural origin. Here, we identified an unusual SRP assemblage (SiC, (Fe,Ni)Si2, and Si0) in situ in an H5-type Jingshan ordinary chondrite. Simultaneously, our analysis showed that the SiC abrasives contain (Fe,Ni)Si2 and Si0 inclusions. Other inclusions in the artificial SiC were similar to those in natural SiC (moissanite) reported in reference data, including diverse metal silicides (e.g., FeSi, FeSi2, Fe3Si7, and Fe5Si3), as well as a light rare earth element-enriched SiO phase and Fe-Mn-Cr alloys. These inclusions were produced by the in situ reduction of silica and the interaction between Si-containing coke and hot metals during the synthesis of the SiC abrasives. The results demonstrate that the SRP assemblage in the Jingshan chondrite originates from abrasive contamination and that the SRP inclusions (with a low content of Ca, Al, Ti, and Zr) cannot be used as a conclusive indicator for natural SiC. Additionally, the morphologies, biaxiality, and polytypes (determined by Raman spectroscopy) of SiC abrasives bear resemblance to those reported for natural SiC, and caution must be exercised when identifying the origin of SRP in samples processed by conventional methods using SiC abrasives. At the end of this paper, we propose more direct and reliable methods for distinguishing between natural and synthetic SiC. Full article
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19 pages, 7350 KiB  
Article
Inhibitory Effects of Polysaccharides on the Dolomitization Reaction of Calcite at 200 °C
by Yang Wei and Hiromi Konishi
Minerals 2024, 14(7), 721; https://doi.org/10.3390/min14070721 - 18 Jul 2024
Viewed by 236
Abstract
This study investigates the impact of dissolved carboxymethyl cellulose (CMC) and agar on the dolomitization reaction of calcite at 200 °C. Previous studies have suggested that CMC and agar promote dolomite precipitation at room temperature. However, this study found that their decomposition products [...] Read more.
This study investigates the impact of dissolved carboxymethyl cellulose (CMC) and agar on the dolomitization reaction of calcite at 200 °C. Previous studies have suggested that CMC and agar promote dolomite precipitation at room temperature. However, this study found that their decomposition products hinder the reaction at 200 °C, with uncertainty about their role at other temperatures. The inhibitory effect of the decomposition products could be attributed to their adsorption onto calcite surfaces, which hinders their dissolution. This results in a longer reaction induction period and replacement period. Regression analysis demonstrates that the 0.1 g/L agar and 0.2 g/L CMC series decrease the cation ordering rate of dolomite produced from synthetic calcite when compared with series without polysaccharides. In contrast, the 0.1 g/L CMC series shows a slight increase in the cation ordering rate compared with series without polysaccharides. The findings of this study suggest a notable potential impact of the decomposition products of polysaccharides on the ordering of dolomite, although it is uncertain whether they inhibit this ordering process. The inhibitory effect observed in the decomposition products of CMC and agar could also exist in the decomposition products of the extracellular polymeric substances (EPS) and bacteria cell walls found in sedimentary rocks during burial diagenesis. Therefore, further research is necessary to understand the role of EPS and bacteria cell walls in dolomitization, since their impact is not always predictable. Full article
(This article belongs to the Special Issue Microbial Biomineralization and Organimineralization)
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15 pages, 5079 KiB  
Article
Effect of Solid Concentration on Particle Size Distribution and Grinding Kinetics in Stirred Mills
by Wang Guo and Keqi Guo
Minerals 2024, 14(7), 720; https://doi.org/10.3390/min14070720 - 17 Jul 2024
Viewed by 329
Abstract
In this study, the evolution behavior of the particle size distribution during the grinding process was examined with fractal theory. According to the distribution index k of the Rosin–Rammler–Benne model, the relationship between the fractal dimension D of the fractal theory and the [...] Read more.
In this study, the evolution behavior of the particle size distribution during the grinding process was examined with fractal theory. According to the distribution index k of the Rosin–Rammler–Benne model, the relationship between the fractal dimension D of the fractal theory and the distribution index k is discussed. The fractal dimension D was used to evaluate the uniformity of the particle size distribution of the grinding product. In addition, the population balance model was used to simulate the breakage behavior of each size interval. The result indicates that the non-first-order model presented a better fitting performance in the breakage behavior of the coarse size and the desired size when compared with the other type of model. It can be found that the breakage rate increased with the solid concentration. However, the breakage distribution function is independent of the solid concentration in this study. These results suggest that the effect of the solid concentration on the fraction of the coarse size broken into the desired size was not significant. Furthermore, the simulated data are discussed and analyzed with the attainable region method as well as the difference in the change rate of the desired size and the overgrinding size. It can be found that to produce a higher fraction of the desired size in the grinding products, the residence time of the material in the mill needs be shortened with a higher solid concentration. Full article
(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
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30 pages, 5946 KiB  
Article
Geochronology, Geochemical Characterization and Tectonic Background of Volcanic Rocks of the Longjiang Formation in the Lengjimanda Plate Area, Middle Da Hinggan Mountains
by Shi-Chang Wang, Yu-Jie Hao, Lu Shi, Zhen Tang and Shuang Zhu
Minerals 2024, 14(7), 719; https://doi.org/10.3390/min14070719 - 16 Jul 2024
Viewed by 305
Abstract
The Lengjimanda plate is situated in the middle section of the Da Hinggan mountains, in the eastern section of the Tianshan Xingmeng orogenic belt. To determine the formation age of the volcanic rocks in the Longjiang formation in this area, to explore their [...] Read more.
The Lengjimanda plate is situated in the middle section of the Da Hinggan mountains, in the eastern section of the Tianshan Xingmeng orogenic belt. To determine the formation age of the volcanic rocks in the Longjiang formation in this area, to explore their origin and tectonic background, and to reconstruct the geodynamic evolution of the region, this study conducted petrological, zircon U–Pb geochronological, geochemical, and isotopic analyses of the volcanic rocks in the Longjiang formation. The Longjiang formation’s volcanic rocks are primarily composed of trachyandesite, trachyte trachydacite, and andesite, which are intermediate basic volcanic rocks. They are enriched in large-ion lithophile elements, are depleted in high-field-strength elements, are significantly fractionated between light and heavy rare earth elements, and exhibit a moderate negative Eu anomaly in most samples. The results of the LA–ICP–MS zircon U–Pb dating indicate that the volcanic rocks in this group were formed in the Early Cretaceous period at 129.1 ± 0.82 Ma. The zircon εHf(t) ranges from +1.13 to +43.77, the tDM2 ranges from +655 to +1427 Ma, the initial Sr ratio (87Sr/86Sr)i ranges from 0.7030 to 0.7036, and the εNd(t) ranges from +2.1 to +6.6. Based on the geochemical compositions and isotopic characteristics of the rocks, the initial magma of the volcanic rocks in the Longjiang formation originated from the partial melting of basaltic crustal materials, with a source material inferred to be depleted mantle-derived young crustal. These rocks were formed in a superimposed post-collisional and continental arc environment, possibly associated with the Mongol-Okhotsk Ocean closure and the oblique subduction of the Pacific plate. This study addresses a research gap regarding the volcanic rocks of the Longjiang formation in this area. Its findings can be applied to exploration and prospecting in the region. Full article
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30 pages, 15303 KiB  
Article
Discovery and Exploration of the Luming Porphyry Mo Deposit, Northeastern China: Implications for Regional Prospecting
by Bangfei Gao, Minghua Dong, Hui Xie, Zhiliang Liu, Yihang Li and Tong Zhou
Minerals 2024, 14(7), 718; https://doi.org/10.3390/min14070718 - 16 Jul 2024
Viewed by 403
Abstract
Over the past two decades, significant deposit discoveries were made in Northeastern China, including the super-large Chalukou, Daheishan, and Luming porphyry Mo deposits. The discovery of the Luming deposit was accomplished through verification of stream sediment anomalies, with mineralization closely associated with early [...] Read more.
Over the past two decades, significant deposit discoveries were made in Northeastern China, including the super-large Chalukou, Daheishan, and Luming porphyry Mo deposits. The discovery of the Luming deposit was accomplished through verification of stream sediment anomalies, with mineralization closely associated with early Jurassic monzogranite and granite porphyry. Previous studies primarily focused on the mineralization mechanisms of these deposits without adequately addressing the exploration methods and prospecting criteria. This study involved a comprehensive re-evaluation of geological observations, analysis of rock primary halo, gravity and magnetic surveys, and induced polarization surveys conducted during exploration campaigns at the Luming porphyry Mo deposit. The results suggest that hydrothermal breccias play a critical role in controlling the mineralization by forming a central low-grade core within the deposit while the Mo mineralization and hydrothermal alteration exhibit a donut-shaped distribution around it. The primary halo shows a distinct metal zonation moving from a central W-Bi-Mo-(Sb) to a peripheral Cu-Co-Ni and a distal Pb-Zn-Ag-In. The mineralization zone exhibits a low Bouguer gravity anomaly, negative magnetic anomaly, medium to low resistivity, and moderate to high chargeability, indicating the effectiveness of geophysical methods in defining the extent of the ore body. The Luming porphyry Mo deposit and distal skarn-epithermal Pb-Zn mineralization are parts of a porphyry-related magmatic-hydrothermal system. The results of this study offer valuable insights into the genesis of porphyry Mo deposits and their implications for prospecting in the forested region of Northeastern China. Full article
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30 pages, 15297 KiB  
Article
Geochronology and Geochemistry of Paleoproterozoic Mafic Rocks in Northern Liaoning and Their Geological Significance
by Jingsheng Chen, Yi Tian, Zhonghui Gao, Bin Li, Chen Zhao, Weiwei Li, Chao Zhang and Yan Wang
Minerals 2024, 14(7), 717; https://doi.org/10.3390/min14070717 - 16 Jul 2024
Viewed by 351
Abstract
Petrological, geochronological, and geochemical analyses of mafic rocks in northern Liaoning were conducted to constrain the formation age of the Proterozoic strata, and to further study the source characteristics, genesis, and tectonic setting. The mafic rocks in northern Liaoning primarily consist of basalt, [...] Read more.
Petrological, geochronological, and geochemical analyses of mafic rocks in northern Liaoning were conducted to constrain the formation age of the Proterozoic strata, and to further study the source characteristics, genesis, and tectonic setting. The mafic rocks in northern Liaoning primarily consist of basalt, diabase, gabbro, and amphibolite. Results of zircon U-Pb chronology reveal four stages of mafic magma activities in northern Liaoning: the first stage of basalt (2209 ± 12 Ma), the second stage of diabase (2154 ± 15 Ma), the third stage of gabbro (2063 ± 7 Ma), and the fourth stage of magmatic protolith of amphibolite (2018 ± 13 Ma). Combined with the unconformity overlying Neoproterozoic granite, the formation age of the Proterozoic strata in northern Liaoning was found to be Paleoproterozoic rather than Middle Neoproterozoic by the geochronology of these mafic rocks. A chronological framework of mafic magmatic activities in the eastern segment of the North China Craton (NCC) is proposed. The mafic rocks in northern Liaoning exhibit compositional ranges of 46.39–50.33 wt% for SiO2, 2.95–5.08 wt% for total alkalis (K2O + Na2O), 6.17–7.50 wt% for MgO, and 43.32–52.02 for the Mg number. TiO2 contents lie between 1.61 and 2.39 wt%, and those of MnO between 0.17 and 0.21 wt%. The first basalt and the fourth amphibolite show low total rare earth element contents. Normalized against primitive mantle, they are enriched in large ion lithophile elements (Rb, Ba, K), depleted in high field strength elements (Th, U, Nb, Ta, Zr, Ti), and exhibit negative anomalies in Sr and P, as well as slight positive anomalies in Zr and Hf. The second diabase and the third gabbro have similar average total rare earth element contents. The diabase shows slight negative Eu anomalies (Eu/Eu* = 0.72–0.88), enrichment in large ion lithophile elements (Ba), depletion in Rb, and slight positive anomalies in high field strength elements (Th, U, Nb, Ta, Zr, Hf, Ti), with negative anomalies in K, Sr, and P. The gabbro is enriched in large ion lithophile elements (Rb, Ba, K), depleted in high field strength elements (Th, U, Nb, Ta, Zr, Hf), and exhibits positive anomalies in Eu (Eu/Eu* = 1.31–1.37). The contents of Cr, Co, and Ni of these four stages of mafic rocks are higher than those of N-MORB. The characteristics of trace element ratios indicate that the mafic rocks belong to the calc-alkaline series and originate from the transitional mantle. During the process of magma ascent and emplacement, it is contaminated by continental crustal materials. There are residual hornblende and spinel in the magma source of the first basalt. The other three magma sources contain residual garnet and spinel. The third gabbro was formed in an island arc environment, and the other three stages of mafic rocks originated from the Dupal OIB and were formed in an oceanic island environment. The discovery of mafic rocks in northern Liaoning suggests that the Longgang Block underwent oceanic subduction and extinction in both the north and south in the Paleoproterozoic, indicating the possibility of being in two different tectonic domains. Full article
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17 pages, 10314 KiB  
Article
Investigating Dynamic Behavior in SAG Mill Pebble Recycling Circuits: A Simulation Approach
by Haijie Li, Gauti Asbjörnsson, Kanishk Bhadani and Magnus Evertsson
Minerals 2024, 14(7), 716; https://doi.org/10.3390/min14070716 - 16 Jul 2024
Viewed by 309
Abstract
The dynamics of milling circuits, particularly those involving Semi-Autogenous Grinding (SAG) mills, are not adequately studied, despite their critical importance in mineral processing. This paper aims to investigate the dynamic behavior of an SAG mill pebble recycling circuit under varying feed ore conditions, [...] Read more.
The dynamics of milling circuits, particularly those involving Semi-Autogenous Grinding (SAG) mills, are not adequately studied, despite their critical importance in mineral processing. This paper aims to investigate the dynamic behavior of an SAG mill pebble recycling circuit under varying feed ore conditions, focusing on both uncontrollable parameters (such as ore hardness) and controllable parameters (including circuit layout and pebble crusher configurations). The study is carried out with Simulink dynamic simulations. Our findings reveal several key insights. Firstly, plant designs based solely on static simulations may not be adequate for large or complex circuits, as they fail to account for the dynamic nature of milling processes. Second, incorporating stockpiles after pebble crushing can effectively mitigate the impact of dynamic fluctuations, leading to more stable circuit performance. Third, different circuit layouts can facilitate easier maintenance and operational flexibility. Notably, finer pebble crushing can enhance circuit throughput by 5% to 10%. Full article
(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
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11 pages, 2013 KiB  
Article
In Situ XRD Measurement for High-Pressure Iron in Laser-Driven Off-Hugoniot State
by Liang Sun, Hao Liu, Xiaoxi Duan, Huan Zhang, Zanyang Guan, Weimin Yang, Xiaokang Feng, Youjun Zhang, Yulong Li, Sanwei Li, Dong Yang, Zhebin Wang, Jiamin Yang, Jin Liu, Wenge Yang, Toshimori Sekine and Zongqing Zhao
Minerals 2024, 14(7), 715; https://doi.org/10.3390/min14070715 - 15 Jul 2024
Viewed by 346
Abstract
The investigation of iron under high pressure and temperatures is crucial to understand the Earth’s core structure and composition and the generation of magnetic fields. Here, we present new in situ XRD measurements for iron in an off-Hugoniot state by laser-driven ramp compression [...] Read more.
The investigation of iron under high pressure and temperatures is crucial to understand the Earth’s core structure and composition and the generation of magnetic fields. Here, we present new in situ XRD measurements for iron in an off-Hugoniot state by laser-driven ramp compression at pressure of 200–238 GPa. The lattice parameters for the hexagonal (hcp)-Fe phase and the c/a ratios were obtained to compare them with previous static and dynamical data, which provides the direct confirmation of such parameters via the different compression paths and strain rates. This work indicates that laser ramp compression can be utilized to provide crystal structure information and direct key information on the crystal structure of Fe at the ultrahigh pressure–temperature conditions relevant for planetology. Full article
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16 pages, 3199 KiB  
Article
Study of a Copper Oxide Leaching in Alkaline Monosodium Glutamate Solution
by Carlos G. Perea, Christian Ihle, Laurence Dyer, Simón Díaz Quezada and Humberto Estay
Minerals 2024, 14(7), 714; https://doi.org/10.3390/min14070714 - 15 Jul 2024
Viewed by 326
Abstract
Oxide copper minerals are commonly extracted via acidic leaching, using acids such as H2SO4, HCl, or HNO3. These strong acids are the most widely used because of their high dissolution kinetics. However, their main concern is the [...] Read more.
Oxide copper minerals are commonly extracted via acidic leaching, using acids such as H2SO4, HCl, or HNO3. These strong acids are the most widely used because of their high dissolution kinetics. However, their main concern is the high acid consumption because copper oxide deposits contain large amounts of acid-consuming gangue. This paper proposes using an alternative aqueous alkaline monosodium glutamate (MSG) system to leach copper oxide minerals. Tenorite (CuO) was used as the copper oxide mineral under study. The influence of process variables (such as temperature and glutamate concentration) and kinetics of this system on copper leaching from tenorite were studied. The results showed that temperature has a significant effect on copper dissolution rates. Increased temperature from 15 °C to 60 °C enhanced the copper extraction from 9.1% to 97.7% after 2 h. Leaching kinetics were analyzed using the shrinking core model (SCM) under various conditions, indicating that the leaching rate presented a mixed control. This method, however, fails to describe leaching for broad particle sizes due to its requirement for single-sized solid grains. This study demonstrated that a large particle size distribution in tenorite supported a successful extension of the SCM for leaching it from mixed glutamate solutions. The activation energy for the 15–60 °C temperature range was calculated to be 102.6 kJ/mol for the chemical control. Full article
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14 pages, 3344 KiB  
Article
Characterization of Kazakhstan’s Clays by Mössbauer Spectroscopy and X-ray Diffraction
by Adilkhan Shokanov, Irina Manakova, Mikhail Vereshchak and Anastassiya Migunova
Minerals 2024, 14(7), 713; https://doi.org/10.3390/min14070713 - 13 Jul 2024
Viewed by 424
Abstract
Studies of the mineralogical composition were carried out, and the features of the clays from the deposits of Kazakhstan were established using Mössbauer spectroscopy (MS) and X-ray diffraction analysis (XRD). According to the XRD results, all the samples were mixed-layer clays of the [...] Read more.
Studies of the mineralogical composition were carried out, and the features of the clays from the deposits of Kazakhstan were established using Mössbauer spectroscopy (MS) and X-ray diffraction analysis (XRD). According to the XRD results, all the samples were mixed-layer clays of the kaolinite–illite type. The lattice parameters of the kaolinite were determined, and it was shown that its structure was disordered and contained a certain amount of impurity in some of the clay samples. A special feature of two of the samples was the additionally identified muscovite polytype 2M1. The spectra of the iron-containing clays were amenable to being resolved into separate components, with similar Mössbauer parameters of the kaolinite, muscovite, illite, and glauconite. The oxidation state of the iron was determined using MS. The predominant part of paramagnetic iron in most samples was in the trivalent state. The primary minerals contributing to Fe2+ were illite and muscovite. The results obtained during the study of the clay samples with complex mineralogical compositions using MS and XRD methods both complemented one another and were found to be in good agreement. Full article
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14 pages, 6880 KiB  
Article
Characteristics of Nanoparticles in Late Pliocene Paleo-Mountain Fire Relics in Jinsuo Basin, Yunnan Province and Their Implications for Paleoclimate Evolution
by Peng Zhang, Bangjun Liu, Yaqin Wang, Lei Zuo, Rui Liu, Jialong Wang and Ru Wang
Minerals 2024, 14(7), 712; https://doi.org/10.3390/min14070712 - 13 Jul 2024
Viewed by 329
Abstract
Wildfires significantly affect climate and environmental changes, closely tied to extreme weather responses. Vegetation combustion emits greenhouse gases (CO2, CH4, CO), warming the climate. Climate shifts, in turn, impact vegetation growth, altering combustible material types and quantities, thus affecting [...] Read more.
Wildfires significantly affect climate and environmental changes, closely tied to extreme weather responses. Vegetation combustion emits greenhouse gases (CO2, CH4, CO), warming the climate. Climate shifts, in turn, impact vegetation growth, altering combustible material types and quantities, thus affecting wildfire intensity, duration, and frequency. Wildfires profoundly affect ecosystems, influenced by factors like atmospheric oxygen and climate. Their combustion gases impact climate and vegetation growth. Recent advancements in studying ancient wildfires include analyzing nanoparticles as key indicators. This study discovered six types of nanoparticles in ancient wildfire remains, with sizes ranging from 50 nm to 500 nm and diverse compositions including elements such as C, O, Mg, Al, Ti, Fe, S, Ca, and P. These findings indicate that wildfires generate a variety of nanoparticles, offering new insights into ancient fire events. Elemental analysis revealed low magnesium but high calcium and aluminum levels, suggesting a warm, humid paleoclimate during these fires. The presence of high Ti-O ratios and carbon-rich nanoparticles points to ground fires with incomplete combustion. This research underscores the significance of nanoparticles in understanding the history and characteristics of ancient wildfires. Full article
(This article belongs to the Section Environmental Mineralogy and Biogeochemistry)
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17 pages, 48563 KiB  
Article
Molecular Dynamic Simulation of the Interaction of a Deep Eutectic Solvent Based on Tetraethylammonium Bromide with La3+ in Acidic Media
by Luver Echeverry-Vargas, Luz M. Ocampo-Carmona and Leopoldo Gutiérrez
Minerals 2024, 14(7), 711; https://doi.org/10.3390/min14070711 - 13 Jul 2024
Viewed by 337
Abstract
In recent years, noticeable progress has been made in the development of alternative extraction systems characterized by greater sustainability. In this context, deep eutectic solvents (DESs) have emerged as a promising alternative to the conventional solvents commonly used in metal extraction. This work [...] Read more.
In recent years, noticeable progress has been made in the development of alternative extraction systems characterized by greater sustainability. In this context, deep eutectic solvents (DESs) have emerged as a promising alternative to the conventional solvents commonly used in metal extraction. This work focuses on investigating the extraction of lanthanum in an aqueous solution of sulfuric acid using a deep eutectic solvent, employing molecular dynamics simulations (MD). The structural characteristics of the solvent and its interactions with the components of the aqueous solution are explored. In this study, tetraethylammonium bromide (TEABr) is combined with ethylene glycol (EG) to form a DES, in which sodium cyanide (NaCN) is subsequently solubilized. According to the results obtained from the MD simulation, the primary interactions in the DESs are established through hydrogen bonds between the bromine and the hydrogens of the methyl group of tetraethylammonium at 3.5 Å, as well as between the bromine and the hydrogens of the methylene group of ethylene glycol at 3.5 Å. Similarly, the main interactions between the binary DES and sodium cyanide occur through the hydrogens of the hydroxyl group of EG and the carbon of cyanide at 1.7 Å, and between the oxygen of the hydroxyl group of EG and the sodium at 2.5 Å. In the acidic solution, the primary interaction is highlighted between the lanthanum ion and the oxygen of the bisulfate at 2.8 Å. Additionally, it is observed that the interaction between the DES and the aqueous solution occurs between the lanthanum and the oxygen of the hydroxyl group of EG, as well as between the lanthanum and the carbon of cyanide at 4.4 Å. It is important to note that, when increasing the temperature from 25 to 80 °C, the interaction distance between the lanthanum and the carbon of cyanide decreases to 2.4 Å, suggesting a possible correlation with the increase in lanthanum extraction, as experimentally observed. Overall, this study underscores the importance of considering the fundamental structural interactions of the DES with the lanthanum acid solution, providing an essential theoretical basis for future experimental investigations. Full article
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18 pages, 84655 KiB  
Article
Petrogenesis and Tectonic Implications of the Granite Porphyry in the Sinongduo Ag-Pb-Zn Deposit, Central Tibet: Constraints from Geochronology, Geochemistry, and Sr-Nd Isotopes
by Peng Zhang, Zhuang Li, Feng Zhao and Xinkai Liu
Minerals 2024, 14(7), 710; https://doi.org/10.3390/min14070710 - 12 Jul 2024
Viewed by 350
Abstract
The Paleocene ore deposits related to the India–Asia continental collision are widely distributed in the Gangdese metallogenic belt. Among these, Sinongduo is the first discovered epithermal Ag-Pb-Zn deposit in the Lhasa terrane. However, there is still controversy over the ore-forming magma in this [...] Read more.
The Paleocene ore deposits related to the India–Asia continental collision are widely distributed in the Gangdese metallogenic belt. Among these, Sinongduo is the first discovered epithermal Ag-Pb-Zn deposit in the Lhasa terrane. However, there is still controversy over the ore-forming magma in this deposit. This study mainly reports new zircon U-Pb isotopic ages, whole-rock geochemistry, and Sr-Nd isotopic data for the granite porphyry from the Sinongduo deposit, aiming to discuss the petrogenesis and tectonic setting of the granite porphyry and its genetic link between the Ag-Pb-Zn mineralization. The results show that zircon U-Pb analyses yield ages of 62.9 ± 0.5 Ma and 59.0 ± 0.7 Ma for the granite porphyry, indicating that it formed during the Paleocene period. The timing of the granite porphyry intrusion is contemporaneous with the mineralization, suggesting that it is most likely the ore-forming magma in the Sinongduo deposit. The granite porphyry has high SiO2 and K2O, moderate Al2O3, and low Na2O, CaO, and FeOT contents, and it displays significant enrichments in LREEs and LILEs and depletions in HREEs and HFSEs, with negative Eu anomaly. The granite porphyry is a peraluminous series and can be classified as S-type granite. Moreover, the granite porphyry shows relatively high ratios of (87Sr/86Sr)i and low values of εNd(t). The geochemical and isotopic compositions of the granite porphyry from the Sinongduo area are similar to those of the upper continental crust, which suggests that the granite porphyry was most likely derived from the melting of the upper continental crust in the Lhasa terrane during the India–Asia collisional tectonic setting. Full article
(This article belongs to the Special Issue Genesis and Evolution of Pb-Zn-Ag Polymetallic Deposits: 2nd Edition)
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22 pages, 23827 KiB  
Article
The Role of Hydrocarbons in the Formation of Uranium Mineralization, Louzhuangzi District, Southern Junggar Basin (China)
by Zhong-Bo He, Bao-Qun Hu, Lin-Fei Qiu, Yun Wang, Hong Chen, Wei-Wei Jia, Yi-Fei Li, Hua-Li Ji and Man-Huai Zhu
Minerals 2024, 14(7), 709; https://doi.org/10.3390/min14070709 - 12 Jul 2024
Viewed by 326
Abstract
In recent years, there have been important breakthroughs in the exploration for sandstone-hosted uranium (U) deposits in the Louzhuangzi district of the southern Junggar Basin. Between 2020 and 2023, a medium-sized sandstone-hosted uranium deposit production area was identified in the region. Only a [...] Read more.
In recent years, there have been important breakthroughs in the exploration for sandstone-hosted uranium (U) deposits in the Louzhuangzi district of the southern Junggar Basin. Between 2020 and 2023, a medium-sized sandstone-hosted uranium deposit production area was identified in the region. Only a few investigations have been conducted at the Louzhuangzi U deposit, including those analyzing its geological–tectonic evolution, basic geological features, hydrogeology, and ore-controlling factors. It is generally believed that uranium mineralization at the Louzhuangzi U deposit is controlled by a redox zone. Organic matter (referred to as OM hereafter) consisting of bitumen and carbonaceous debris is very common in the uranium ores (especially in high-grade ores) at the Louzhuangzi U deposit. However, the characteristics of the OM and its contribution to uranium’s mineralization have not been studied in detail. In this study, OM-rich U-ores, altered sandstone, and barren sandstone samples were collected for petrography, mineralogical, micro-spectroscopy, carbon, and sulfur isotope studies. The results of this study show that the distribution of U minerals and metal sulfides (pyrite, sphalerite, etc.) was strictly controlled by bitumen at the Louzhuangzi U deposit. The bitumen may have been formed by hydrocarbon-rich and U-rich ore-forming fluids, which were formed after hydrocarbon generation and expulsion in the underlying Jurassic coal-bearing source rocks. The fluids contained U, Zn, Fe, and other metal elements, which migrated together and then precipitated into the oxidized Toutunhe Formation sandstone through cracking and differentiation processes. Therefore, the results indicate that migrated hydrocarbons were involved in U mineralization, in addition to oxidation–reduction processes, in the Louzhuangzi district, south of the Junggar Basin (China). Full article
(This article belongs to the Special Issue Uranium: Geochemistry and Mineralogy)
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24 pages, 6179 KiB  
Article
The Devonian Kalarskoe Epithermal Occurrence of the Kaburchak Au-Ag Cluster in the Altai-Sayan Folded Area, Russia: Geological Setting; Mineralogical, Geochemical, and Geochronological Features
by Alexander I. Chernykh, Polina N. Leibham, Lidia A. Sokolova, Olga V. Yakubovich, Maria O. Anosova and Evgeny A. Naumov
Minerals 2024, 14(7), 708; https://doi.org/10.3390/min14070708 - 12 Jul 2024
Viewed by 337
Abstract
Prospecting efforts to located Au mineralization within the Altai-Sayan fold area (ASFA) over previous decades have revealed that Devonian epithermal Au-Ag mineralization is more widespread than previously recognized. The preservation of this type of mineralization in Paleozoic rocks offers new prospects for the [...] Read more.
Prospecting efforts to located Au mineralization within the Altai-Sayan fold area (ASFA) over previous decades have revealed that Devonian epithermal Au-Ag mineralization is more widespread than previously recognized. The preservation of this type of mineralization in Paleozoic rocks offers new prospects for the exploration of Au-Ag deposits in the underexplored region of Gornaya Shoria. The Kalarskoe epithermal Au-Ag occurrence represents Devonian epithermal mineralization within the Kaburchak cluster, Gornaya Shoria, Russia. This occurrence is confined to zones of argillic alteration that were superimposed on previously formed propylites. The argillic-altered rocks host quartz-sulfide veinlet zones. The mineralization of the Kalarskoe site is characterized by a high abundance of sulfide minerals: commonly, 5%–10%; often, up to 20%; and in some cases, up to 60%–70%. The ore minerals are represented by pyrite, arsenopyrite, sphalerite, galena, chalcopyrite, fahlores, native Au, and electrum, as well as by the sulfosalts Pb, Bi, Ag, Cu, and the tellurides of Au, Ag, and Pb. Based on mineralogical observations, at least four generations of sulfide mineral formations are distinguished within the ore occurrence. The mineralization of the Kalarskoe ore occurrence may be assigned to the intermediate sulfidation (IS) type. The results of the (U,Th)-He dating of pyrite from the pyrite-arsenopyrite massive body (pyr-3 and 4) revealed the protracted history of the mineralization in the intervals from ~399 to ~371 Ma. The obtained results substantially enhance the prospecting models for the exploration of epithermal Au-Ag deposits in the western part of the Altai-Sayan fold area (ASFA). Full article
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21 pages, 3649 KiB  
Article
Comparing the Performance of Hydrocyclones and High-Frequency Screens in an Industrial Grinding Circuit: Part I—Size Separation Assessments
by Bruna Silveira Costa, Maurício Guimarães Bergerman and Homero Delboni Júnior
Minerals 2024, 14(7), 707; https://doi.org/10.3390/min14070707 - 12 Jul 2024
Viewed by 290
Abstract
Industrial ball milling circuits usually include hydrocyclones in a closed configuration to achieve a specified grinding size. Although hydrocyclones are relatively simple to operate, their classification performance is generally low, leading to significant fines recirculation within the circuit, consequently overgrinding the product. Conversely, [...] Read more.
Industrial ball milling circuits usually include hydrocyclones in a closed configuration to achieve a specified grinding size. Although hydrocyclones are relatively simple to operate, their classification performance is generally low, leading to significant fines recirculation within the circuit, consequently overgrinding the product. Conversely, high-frequency screening potentially shows a relatively higher separation efficiency, as the entrainment of fines to the coarse product is significantly reduced. The present work compares the performance of hydrocyclones—HC and high-frequency screens—HFS based on four surveys conducted in Nexa’s Vazante Zinc ore industrial grinding circuit in Vazante, Brazil, which processes zinc silicate ore. The comparisons included the partition of solids, water split, and particle size distributions. Whiten’s partition curve model was adopted to obtain the selected performance parameters through mass balancing the experimental data. The industrial surveys comprised three different size separation configurations, i.e., HC-Only, HFS-Only, and a combined HC-HFS setup. In all cases, the assessments consistently indicated higher separation performances with HFS compared to the HC operation. The final product associated with the HC+HFS configuration showed a narrower size distribution around the grinding size. Full article
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13 pages, 4836 KiB  
Article
Effect of the Interaction between Clays and Cations on Froth Rheology in Flotation
by Chao Li, Zhongren Wu, Zhihang Wu, Xianggen Chen and Yijun Cao
Minerals 2024, 14(7), 706; https://doi.org/10.3390/min14070706 - 12 Jul 2024
Viewed by 288
Abstract
The significance of froth rheology in affecting flotation performance is widely acknowledged. Clays could deteriorate flotation performance by altering froth rheology. The presence of cations further complicates the flotation system. Thus far, the interaction between clay minerals and cations and their impact on [...] Read more.
The significance of froth rheology in affecting flotation performance is widely acknowledged. Clays could deteriorate flotation performance by altering froth rheology. The presence of cations further complicates the flotation system. Thus far, the interaction between clay minerals and cations and their impact on froth rheology remains unclear. The present work selected three typical clays and cations with two valences (Na+ and Ca2+) to investigate their interacting influences on froth rheology. The results indicate that clays exhibit diverse froth rheological behaviors, with increasing cation strength from 0 to 0.1 mol/L. For montmorillonite, the froth viscosity initially decreased and subsequently increased. For kaolinite, upon the addition of cations, there was a significant decrease in froth viscosity; nevertheless, froth viscosity barely changed as the valency and concentration of the cations increased. Talc produced a considerably more viscous froth, and froth viscosity continued to rise with increasing concentrations of cations. The underlying mechanisms of the different responses in froth rheology were also investigated. The findings of this work have the potential to advance the optimization of flotation for complex ores containing clay minerals in high-salt processing water. Full article
(This article belongs to the Special Issue Interfacial Chemistry of Critical Mineral Flotation)
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