Minerals

17 pages, 5039 KiB

Open AccessArticle

Occurrences of the Rare, REE Minerals Daqingshanite, Törnebohmite, Biraite, Sahamalite, and Ferriperbøeite from the Sheep Creek Area, Montana, USA

by Christopher H. Gammons, Sarah Risedorf, Gary Wyss and Heather Lowers

Minerals 2024, 14(10), 1047; https://doi.org/10.3390/min14101047 (registering DOI) - 18 Oct 2024

Abstract

Over 30 small, discontinuous, tabular carbonatite bodies are located in the Sheep Creek area, Ravalli County, southwest Montana. The age and origin of these REE-Nb-rich deposits are currently being investigated. The purpose of this paper is to document the occurrence of several rare [...] Read more.

Over 30 small, discontinuous, tabular carbonatite bodies are located in the Sheep Creek area, Ravalli County, southwest Montana. The age and origin of these REE-Nb-rich deposits are currently being investigated. The purpose of this paper is to document the occurrence of several rare minerals, including daqingshanite, törnebohmite, biraite, sahamalite, and ferriperbøeite, in two of the carbonatite bodies. These minerals are found in association with monazite, hydroxylbastnäsite, ferriallanite, calcite, dolomite, baryte, quartz, actinolite, apatite, celsian, and Sr-rich aragonite. Automated SEM-EDS was used to target the areas of interest in polished specimens for more detailed spot SEM-EDS and electron probe microanalysis. Raman spectra were also acquired for each of the rare minerals. The complex mineralogy of the Sheep Creek carbonatites is most likely due to several overlapping thermal events, including primary magmatic, overprinting hydrothermal, and supergene weathering stages. The rare minerals described in this study are believed to be hydrothermal and/or carbothermal in origin, although no estimates of temperature are available at this time. Full article

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

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20 pages, 8601 KiB

Open AccessArticle

Mechanisms of Reservoir Space Preservation in Ultra-Deep Shales: Insights from the Ordovician–Silurian Wufeng–Longmaxi Formation, Eastern Sichuan Basin

by Pengwan Wang, Xiaolong He, Ya’na Chen, Chuan Xu, Quanbin Cao, Kai Yang and Bing Zhang

Minerals 2024, 14(10), 1046; https://doi.org/10.3390/min14101046 - 18 Oct 2024

Abstract

This study aims to explore the reservoir characteristics and formation mechanisms of ultra-deep shale gas in the Ordovician–Silurian Wufeng–Longmaxi Formation in the Sichuan Basin in order to provide theoretical support and practical guidance for the exploration and development of ultra-deep shale gas. With [...] Read more.

This study aims to explore the reservoir characteristics and formation mechanisms of ultra-deep shale gas in the Ordovician–Silurian Wufeng–Longmaxi Formation in the Sichuan Basin in order to provide theoretical support and practical guidance for the exploration and development of ultra-deep shale gas. With recent breakthroughs in ultra-deep shale gas exploration, understanding its organic matter development, mineral composition, and reservoir space characteristics has become particularly important. The background of this research lies in the significant potential of ultra-deep shale gas, which remains inadequately understood, necessitating an in-depth analysis of its pore structure and reservoir quality. Through a systematic study of the ultra-deep shale in well FS1 of Sichuan Basin, that the following was found: (i) The ultra-deep shale in the Wufeng–Longmaxi Formation is mainly composed of quartz and clay minerals, exhibiting high total organic carbon (TOC) and high porosity characteristics, indicating it is in an overmature thermal evolution stage. (ii) Organic pores and microcracks in the ultra-deep shale are more developed compared to middle-shallow and deep shale, forming a complex pore structure that is conducive to gas storage. (iii) In the diagenesis process, the dissolution and recrystallization of the biogenic skeleton promote the cementation between autogenetic quartz particles, forming a rigid skeleton that effectively inhibits the impact of mechanical compaction. (iv) The overpressure environment created by the hydrocarbon generation process, along with gas production from hydrocarbon cracking, can effectively offset the mechanical compaction of overburden pressure on micropores, and this overpressure environment also promotes the further development of microfractures, which is beneficial for the development and preservation of ultra-deep shale pores. In summary, this study not only reveals the reservoir characteristics and formation mechanisms of ultra-deep shale but also provides essential references for the exploration and development of ultra-deep shale gas in the Sichuan Basin and similar regions, emphasizing the ongoing significance of research in this field. Full article

(This article belongs to the Topic Geomechanics and Engineering Evaluation of Fractured Oil and Gas Reservoirs)

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27 pages, 11358 KiB

Open AccessArticle

Geochemistry and Mineralogy of Upper Paleozoic Coal in the Renjiazhuang Mining District, Northwest Ordos Basin, China: Evidence for Sediment Sources, Depositional Environment, and Elemental Occurrence

by Meng Wu, Yong Qin, Guchun Zhang, Jian Shen, Jianxin Yu, Xiaoyan Ji, Shifei Zhu, Wenqiang Wang, Yali Wan, Ying Liu and Yunhu Qin

Minerals 2024, 14(10), 1045; https://doi.org/10.3390/min14101045 - 18 Oct 2024

Abstract

This study aims to investigate the depositional environment, sediment sources, and elemental occurrence of Upper Paleozoic coal in the Renjiazhuang Mining District, Western Ordos Basin. Furthermore, SEM-EDX, optical microscope (OM), ICP-AES, ICP-MS, and AAS were used. Compared with hard coal of the world, [...] Read more.

This study aims to investigate the depositional environment, sediment sources, and elemental occurrence of Upper Paleozoic coal in the Renjiazhuang Mining District, Western Ordos Basin. Furthermore, SEM-EDX, optical microscope (OM), ICP-AES, ICP-MS, and AAS were used. Compared with hard coal of the world, M3 coals were enriched in Ga, Li, Zr, Be, Ta, Hf, Nb, Pb, and Th, M5 coals were enriched in Li (CC = 10.21), Ta (CC = 6.96), Nb (CC = 6.95), Be, Sc, Ga, Hf, Th, Pb, Zr, In, and REY, while M9 coals were enriched in Li (CC = 14.79), Ta (CC = 5.41), Ga, W, Hf, Nb, Zr, Pb, and Th. In addition, minerals were mainly composed of kaolinite, dolomite, pyrite, feldspar, calcite, and quartz, locally visible minor amounts of monazite, zircon, clausthalite, chalcopyrite, iron dolomite, albite, fluorite, siderite, galena, barite, boehmite, and rutile. In addition, maceral compositions of M3 coals and M9 coals were dominated by vitrinite (up to 78.50%), while M5 coals were the main inertite (up to 76.26%), and minor amounts of liptinite. REY distribution patterns of all samples exhibited light REY enrichment and negative Eu anomalies. The geochemistry of samples (TiO₂ and Al₂O₃, Nb/Y and Zr × 0.0001/TiO₂ ratios, and REY enrichment types) indicates that the sediment sources of samples originated from felsic igneous rocks. Indicator parameters (TPI, GI, VI, GWI, V/I, Sr/Ba, Th/U, and Ce_N/Ce_N*) suggest that these coals were formed in different paleopeat swamp environments: M3 coal was formed in a lower delta plain and terrestrial (lacustrine) facies with weak oxidation and reduction, and M5 coal was formed in a terrestrial and dry forest swamp environment with weak oxidation–oxidation, while M9 coal was formed in a seawater environment of humid forest swamps and the transition from the lower delta plain to continental sedimentation with weak oxidation and reduction. Statistical methods were used to study the elemental occurrence. Moreover, Li, Ta, Hf, Nb, Zr, Pb, and Th elements were associated with aluminosilicates, and Ga occurred as silicate. Full article

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

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20 pages, 4378 KiB

Open AccessArticle

A Comparison Study on the Recovery of REEs from Red Mud by Sulfation Roasting–Water Leaching and Citric Acid Leaching

by Hossein Shalchian, Mohsen Hajizadeh Navakh, Ionela Birloaga, Abolfazl Babakhani and Francesco Vegliò

Minerals 2024, 14(10), 1044; https://doi.org/10.3390/min14101044 - 18 Oct 2024

Abstract

In this study, the recovery of rare earth elements (REEs) from red mud (bauxite residue) was explored through a combination of citric acid leaching and sulfation roasting–water leaching processes, introducing an innovative approach to the field. The research uniquely investigates the influence of [...] Read more.

In this study, the recovery of rare earth elements (REEs) from red mud (bauxite residue) was explored through a combination of citric acid leaching and sulfation roasting–water leaching processes, introducing an innovative approach to the field. The research uniquely investigates the influence of citric acid on the leaching behavior of REEs and impurities in both untreated red mud and red mud subjected to sulfation roasting, providing a direct comparison of these methodologies. A novel aspect of this study is the evaluation of solvent extraction efficiency using DEHPA, highlighting the selective recovery of REEs over impurities from both citric acid and water-leaching solutions. Furthermore, a comprehensive phase analysis using X-ray diffraction (XRD) was conducted to track the transformations of minerals during the sulfation roasting process, an original contribution to the literature. The findings revealed that over 85% of REEs and major elements such as Fe, Al, Ca, and Ti dissolved in water after sulfation at 105 °C, while iron and titanium dissolution significantly decreased following roasting at 725 °C. Importantly, terbium, neodymium, and gadolinium extraction efficiencies were notably affected by roasting temperature. Citric acid leaching results demonstrated that the direct leaching of red mud leads to higher leaching efficiency than leaching it after the roasting process. Solvent extraction demonstrated lower terbium and neodymium recovery from citric acid solutions compared to water leaching solution. Finally, stripping experiments illustrated that 6M H₂SO₄ solution is capable of stripping more than 80% of rare earth elements, except terbium. Full article

(This article belongs to the Special Issue Recycling of Mining and Solid Wastes)

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17 pages, 3832 KiB

Open AccessArticle

Acceleration of Numerical Modeling of Uranium In Situ Leaching: Application of IDW Interpolation and Neural Networks for Solving the Hydraulic Head Equation

by Maksat B. Kurmanseiit, Madina S. Tungatarova, Banu Z. Abdullayeva, Daniar Y. Aizhulov and Nurlan M. Shayakhmetov

Minerals 2024, 14(10), 1043; https://doi.org/10.3390/min14101043 - 18 Oct 2024

Abstract

The application of In Situ Leaching (ISL) has significantly boosted uranium production in countries like Kazakhstan. Given that hydrodynamic and chemical processes occur underground, mining enterprises worldwide have developed models of reactive transport. However, modeling these complex processes demands considerable computational resources. This [...] Read more.

The application of In Situ Leaching (ISL) has significantly boosted uranium production in countries like Kazakhstan. Given that hydrodynamic and chemical processes occur underground, mining enterprises worldwide have developed models of reactive transport. However, modeling these complex processes demands considerable computational resources. This issue is particularly significant in the context of numerical analyses of mining processes or when modeling production scenarios in uranium mining by the ISL technique, given that a substantial portion of computational resources is allocated to solving the hydraulic head equation. This work aims to explore the applicability of PINNs to accelerate hydrodynamic simulations of the ISL process. The solution of the Poisson equation is accelerated by generating an initial approximation for the iterative method through the application of the Inverse Distance Weighting (IDW) interpolation and PINNs. The impact of various factors, including the computational grid and the spacing between wells, on both the accuracy and efficiency of initial approximation and the overall solution of the elliptic equation are explored. Employing the hydraulic head distribution obtained through PINNs as the initial approximation led to a significant reduction in computation time and a decrease in the number of iterations by a factor of 2.8 to 7.10. Full article

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

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15 pages, 6629 KiB

Open AccessArticle

The Contribution of Carbonaceous Material to Gold Mineralization in the Huangjindong Deposit, Central Jiangnan Orogen, China

by Yueqiang Zhou, Zhilin Wen, Yongjun Liu, Jun Wu, Baoliang Huang, Hengcheng He, Yuxiang Luo, Peng Fan, Xiang Wang, Xiaojun Liu, Teng Deng, Ming Zhong, Shengwei Zhang and Mei Xiao

Minerals 2024, 14(10), 1042; https://doi.org/10.3390/min14101042 - 17 Oct 2024

Abstract

The Huangjindong gold deposit in northeastern Hunan is one of the most representative gold deposits in the Jiangnan Orogenic Belt. The orebodies are mainly hosted in the Neoproterozoic Lengjiaxi Group, which comprises carbonaceous slates. Abundant carbonaceous material (CM) can be found in the [...] Read more.

The Huangjindong gold deposit in northeastern Hunan is one of the most representative gold deposits in the Jiangnan Orogenic Belt. The orebodies are mainly hosted in the Neoproterozoic Lengjiaxi Group, which comprises carbonaceous slates. Abundant carbonaceous material (CM) can be found in the host rocks and ore-bearing quartz veins, but its geological characteristics and genesis, as well as its association with gold mineralization, are still unclear. Systematic petrographic observation demonstrated two types of CM in host rocks and ores, i.e., CM1 and CM2. Among them, CM1 is the predominant type and mainly occurs in the layered carbonaceous slates, while CM2 is mostly present in quartz veins and mineralized host rocks. Laser Raman spectroscopic analyses of CM1 were performed at higher temperatures (376–504 °C), and CM2 was generated at similar temperatures (255–435 °C) to gold mineralization. Combined with previous studies, we can conclude that CM1 was produced by Neoproterozoic to early Paleozoic metamorphism before gold mineralization, while CM2 is of hydrothermal origin. Geochemical modeling indicates that CM1 could promote gold precipitation through reduction, as well as facilitate structure deformation and metal absorption as previously proposed. However, hydrothermal CM2 is favorable for gold mineralization because it triggers sulfidation, similar to other Fe-bearing minerals (such as siderite) in the host rocks. Consequently, both types of CM in the Huangjindong deposit are favorable for gold mineralization and carbonaceous slates could be important gold-bearing units for future ore prospecting in the Jiangnan Orogen as well as other places in South China. Full article

(This article belongs to the Special Issue Microanalysis Applied to Mineral Deposits)

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15 pages, 3180 KiB

Open AccessArticle

Influence of Particle Size on Flotation Separation of Ilmenite and Forsterite

by Senpeng Zhang, Yaohui Yang, Donghui Wang, Weiping Yan and Weishi Li

Minerals 2024, 14(10), 1041; https://doi.org/10.3390/min14101041 - 17 Oct 2024

Abstract

In addition to bubble–particle interaction, particle–particle interaction also has a significant influence on mineral flotation. Fine particles that coat the mineral surface prevent direct contact with collectors and/or air bubbles, thereby lowering flotation recovery. Calculating the particle interaction energy can help in evaluating [...] Read more.

In addition to bubble–particle interaction, particle–particle interaction also has a significant influence on mineral flotation. Fine particles that coat the mineral surface prevent direct contact with collectors and/or air bubbles, thereby lowering flotation recovery. Calculating the particle interaction energy can help in evaluating the interaction behavior of particles. In this study, the floatability of coarse ilmenite (−151 + 74 μm) and different particle sizes (−45 + 25, −25 + 19, −19 μm) of forsterite with NaOL as a collector was investigated. The results showed that forsterite sizes of −45 + 25 and −25 + 19 μm had no effect on the ilmenite floatability, whereas −19 μm forsterite significantly reduced ilmenite floatability. A particle size analysis of artificially mixed minerals and a scanning electron microscopy (SEM) analysis of the flotation products showed that heterogeneous aggregation occurred between ilmenite and −19 μm forsterite particles. The extended DLVO (Derjaguin–Landau–Verwey–Overbeek) theory was applied to calculate the interaction energy between mineral particles using data from zeta potential and contact angle measurements. The results showed that the interaction barriers between ilmenite (−151 + 74 μm) and forsterite (−45 + 25, −25 + 19, and −19 μm) were 11.94 × 10³ kT, 8.23 × 10³ kT and 4.09 × 10³ kT, respectively. Additionally, the interaction barrier between forsterite particles smaller than 19 μm was 0.51 × 10³ kT. The strength of the barrier decreased as the size of the forsterite decreased. Therefore, fine forsterite particles and aggregated forsterite can easily overcome the energy barrier, coating the ilmenite particle surface. This explains the effect of different forsterite sizes on the floatability of ilmenite and the underlying mechanism of particle interaction. 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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17 pages, 3569 KiB

Open AccessArticle

A Cippus from Turris Libisonis: Evidence for the Use of Local Materials in Roman Painting on Stone in Northern Sardinia

by Roberta Iannaccone, Stefano Giuliani, Sara Lenzi, Matteo M. N. Franceschini, Silvia Vettori and Barbara Salvadori

Minerals 2024, 14(10), 1040; https://doi.org/10.3390/min14101040 - 17 Oct 2024

Abstract

The ancient Roman town of Turris Libisonis was located on the northern coast of Sardinia and was known in the past as an important naval port. Located in the Gulf of Asinara, it was a Roman colony from the 1st century BCE and [...] Read more.

The ancient Roman town of Turris Libisonis was located on the northern coast of Sardinia and was known in the past as an important naval port. Located in the Gulf of Asinara, it was a Roman colony from the 1st century BCE and became one of the richest towns on the island. Among the archaeological finds in the area, the cippus exhibited in the Antiquarium Turritano is of great interest for its well-preserved traces of polychromy. The artefact dates back to the early Imperial Age and could have had a funerary or votive function. The artefact was first examined using a portable and non-invasive protocol involving multi-band imaging (MBI), portable X-ray fluorescence (p-XRF), portable FT-IR in external reflectance mode (ER FT-IR) and Raman spectroscopy. After this initial examination, a few microfragments were collected and investigated by optical microscopy (OM), X-ray powder diffraction (XRPD), Fourier-transform infrared spectroscopy in ATR mode (ATR FT-IR) and micro-ATR mode (μATR FT-IR) and Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM-EDS) to improve our knowledge and characterize the materials and to determine their provenience. The results contribute to a better understanding of the provenance of materials and shed light on pigments on stone and their use outside the Italian peninsula and, in particular, Roman Sardinia. Full article

(This article belongs to the Special Issue Geomaterials and Cultural Heritage)

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20 pages, 14818 KiB

Open AccessArticle

Control of Seepage Characteristics in Loose Sandstone Heap Leaching with Staged Particle Sieving-Out Method

by Quan Jiang, Mingtao Jia, Yihan Yang and Chuanfei Zhang

Minerals 2024, 14(10), 1039; https://doi.org/10.3390/min14101039 - 17 Oct 2024

Abstract

This paper studies the influence of the staged particle sieving-out method on the seepage characteristics in loose sandstone heap leaching. The staged sieving out of ore sample particles was conducted according to particle size, and ground pressure was applied to them. Subsequently, parameters [...] Read more.

This paper studies the influence of the staged particle sieving-out method on the seepage characteristics in loose sandstone heap leaching. The staged sieving out of ore sample particles was conducted according to particle size, and ground pressure was applied to them. Subsequently, parameters such as the permeability, particle distribution, and pore distribution characteristics of the rock samples were obtained to investigate the influence of the staged particle sieving-out method on the seepage effect of loose sandstone heap leaching. The results indicate that sieving out particles smaller than 0.15 mm can significantly reduce the probability of hole blockage and increase the overall pore size, greatly enhancing permeability. Sieving out particles with sizes between 0.15 mm and 1.2 mm can result in the loss of skeleton particles, reducing the amount of flow channels and thereby decreasing permeability. Sieving out particles larger than 1.2 mm can reduce the overall particle size of rock samples, improve strength and pressure stability, and help maintain permeability. In the surface heap leaching of loose sandstone ore, by sieving out particles smaller than 0.15 mm during deep heap construction and sieving out particles larger than 1.2 mm during mid-level heap construction, and by using vat leaching for sieved-out particles, the seepage effect of the ore heap can be significantly optimized, and complete utilization of resources can be ensured. Full article

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

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42 pages, 113259 KiB

Open AccessArticle

Hypogene Alteration of Base–Metal Mineralization at the Václav Vein (Březové Hory Deposit, Příbram, Czech Republic): The Result of Recurrent Infiltration of Oxidized Fluids

by Zdeněk Dolníček, Jiří Sejkora and Pavel Škácha

Minerals 2024, 14(10), 1038; https://doi.org/10.3390/min14101038 - 17 Oct 2024

Abstract

The Václav vein (Březové Hory deposit, Příbram ore area, Czech Republic) is a base–metal vein containing minor Cu-Zn-Pb-Ag-Sb sulfidic mineralization in a usually hematitized gangue. A detailed mineralogical study using an electron microprobe revealed a complicated multistage evolution of the vein. Early siderite [...] Read more.

The Václav vein (Březové Hory deposit, Příbram ore area, Czech Republic) is a base–metal vein containing minor Cu-Zn-Pb-Ag-Sb sulfidic mineralization in a usually hematitized gangue. A detailed mineralogical study using an electron microprobe revealed a complicated multistage evolution of the vein. Early siderite and Fe-rich dolomite were strongly replaced by assemblages of hematite+rhodochrosite and hematite+kutnohorite/Mn-rich dolomite, respectively. In addition, siderite also experienced strong silicification. These changes were associated with the dissolution of associated sulfides (sphalerite, galena). The following portion of the vein contains low-Mn dolomite and calcite gangue with Zn-rich chlorite, wittichenite, tetrahedrite-group minerals, chalcopyrite, bornite, and djurleite, again showing common replacement textures in case of sulfides. The latest stage was characterized by the input of Ag and Hg, giving rise to Ag-Cu sulfides, native silver (partly Hg-rich), balkanite, and (meta)cinnabar. We explain the formation of hematite-bearing oxidized assemblages at the expense of pre-existing “normal” Příbram mineralization due to repeated episodic infiltration of oxygenated surface waters during the vein evolution. Episodic mixing of ore fluids with surface waters was suggested from previous stable isotope and fluid inclusion studies in the Příbram ore area. Our mineralogical study thus strengthens this genetic scenario, illustrates the dynamics of fluid movement during the evolution of a distinct ore vein structure, and shows that the low content of ore minerals cannot be necessarily a primary feature of a vein. Full article

(This article belongs to the Special Issue Mineralogy and Geochemistry of Polymetallic Ore Deposits)

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18 pages, 13198 KiB

Open AccessArticle

Microfacies and Evolution of the Carbonate Factory During the Middle Permian in Northwest Sichuan Basin, China

by Siyu Zhou, Dakang Zhong, Haitao Sun, Xiaojie Huang, Chenguang Wang and Xuanwei Liu

Minerals 2024, 14(10), 1037; https://doi.org/10.3390/min14101037 - 17 Oct 2024

Abstract

Located in the eastern Paleo-Tethys Ocean and near the equator, carbonate sedimentation widely developed in the Sichuan Basin in the Permian Guadalupian period. Although the growth and decline of carbonate particles are closely related to the surrounding sedimentary environment, the relationships between the [...] Read more.

Located in the eastern Paleo-Tethys Ocean and near the equator, carbonate sedimentation widely developed in the Sichuan Basin in the Permian Guadalupian period. Although the growth and decline of carbonate particles are closely related to the surrounding sedimentary environment, the relationships between the grain composition and distribution of the northwest Sichuan Basin and the sedimentary environment are not clear. This study explored the particle type, particle content, and sedimentary structure of 300 thin sections from 19 wells and seven field profiles of the Guadalupian period in the northwest Sichuan Basin, identified seven microfacies and four microfacies associations, analyzed the sedimentary environment, and established a sedimentary evolution model. The results show that there was a warm-water Dasycladaceae-dominated and foraminifera-dominated open platform developed in the early Roadian era in the research area. As the climate cooled during the late Roadian era, the warm-water carbonate sedimentary environment was replaced by a cold-water bryozoan-dominated and echinoid-dominated marginal sedimentary environment. As the climate continued to cool and the sea level dropped, the platform margin grain beach sediment underwent further development in the early Wordian era. In the late Wordian era stage, the sedimentary environment was influenced by the Dongwu movement, resulting in sea level changes and acidification caused by hydrothermal activities, which reduced the degree of grain beach development. During the Capitanian era, the climate became warmer due to the eruption of the ELIP. The uplift caused by the Dongwu movement resulted in a relative shallowing of the platform margin region, and hence, the grain beach sediment only developed in the southwest, while the northeast was dominated by deepwater basin sediments. The sudden transition from a warm-water, autotroph-dominated carbonate open platform to a cold-water, heterozoan-dominated carbonate platform margin resulted from a combination of tectonic movements, rapid sea level changes, and sedimentary environment changes during the Guadalupian era. Full article

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16 pages, 2775 KiB

Open AccessArticle

Pyrite Depression by Sodium Metabisulfite in Freshwater and Seawater with Copper Activation

by César I. Castellón, Pedro Toledo, Francisco Rojas, Felipe D. Sepúlveda and Ricardo I. Jeldres

Minerals 2024, 14(10), 1036; https://doi.org/10.3390/min14101036 - 16 Oct 2024

Abstract

Pyrite has natural floatability and thus readily enters valuable mineral flotation concentrates, diluting their quality and decreasing their economic value. Its separation is challenging, depending on process conditions, the presence of activating ions, and water quality, particularly in regions where seawater is used. [...] Read more.

Pyrite has natural floatability and thus readily enters valuable mineral flotation concentrates, diluting their quality and decreasing their economic value. Its separation is challenging, depending on process conditions, the presence of activating ions, and water quality, particularly in regions where seawater is used. This study examines the effect of various doses of sodium metabisulfite (SMBS) on pyrite depression in freshwater and seawater under weakly alkaline conditions and with different copper ion concentrations. Without the addition of activators or depressants, pyrite recovery is 40% in freshwater and 60% in seawater, whereas with 10 ppm of SMBS, recoveries drop to 28% and 38%, respectively. The addition of 10 ppm Cu²⁺ increases recovery by 10% in freshwater and by 20% in seawater. In the presence of 75 ppm of PAX, maximum recovery reached 50% in freshwater and 80% in seawater. These results suggest that cationic bridges formed by seawater ions, combined with CaOH⁺ activation, play a critical role in pyrite activation, even in the presence of depressants. Full article

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

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25 pages, 19369 KiB

Open AccessArticle

Applying Alkali Activator and Hydrophobic Agents in Clay-Based Mortars for Enhanced Properties

by Aspasia Karozou, Fotini Kesikidou, Eleni Pavlidou and Maria Stefanidou

Minerals 2024, 14(10), 1035; https://doi.org/10.3390/min14101035 - 15 Oct 2024

Abstract

Clay-based mortars are susceptible to water intake and exhibit low mechanical strength, presenting challenges in their application within the construction sector. This research addresses these vulnerabilities by investigating the combination of alkali activators with waterproofing agents, specifically a nano-clay and an acrylic emulsion, [...] Read more.

Clay-based mortars are susceptible to water intake and exhibit low mechanical strength, presenting challenges in their application within the construction sector. This research addresses these vulnerabilities by investigating the combination of alkali activators with waterproofing agents, specifically a nano-clay and an acrylic emulsion, to enhance the properties of clay mortars. Alkali-activated materials are known for their superior mechanical properties and sustainable potential, especially when derived from low-cost by-products. Recent studies have focused on alkali activation using clays and soils as precursors to improve their physical and mechanical properties while increasing durability. However, the high absorbency of these mortars remains a concern, as it can lead to matrix degradation. Therefore, to address these problems, this research studied the combination of a highly alkaline activator (potassium metasilicate) with hydrophobic agents, such as a nano-clay and an acrylic emulsion, using two different clayey soils. The results indicated that potassium metasilicate (PO) enhanced the mechanical properties and stability for both aluminosilicate systems, while nano-clay (PONC) significantly reduced the capillary absorption through time, especially in A2 systems. The addition of acrylic emulsion (POD) proved highly effective in both systems, significantly improving durability. By integrating these agents, the mortar systems were protected against water intake, while durable construction materials were formed. Full article

(This article belongs to the Special Issue Alkali Activation of Clay-Based Materials)

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19 pages, 5770 KiB

Open AccessArticle

Genesis of the Wuchiapingian Formation Tuffs and Their Relationship with the Tectonic Background of the Kaijiang–Liangping Trough in the Northern Sichuan Basin

by Limin Qin and Xiaodong Lan

Minerals 2024, 14(10), 1034; https://doi.org/10.3390/min14101034 - 15 Oct 2024

Abstract

Controversy surrounds the forming time and tectonic background of the Kaijiang–Liangping Trough in the northern Sichuan Basin. The Wuchiapingian Formation, surrounding this Late Permian trough, contains tuffs, and industrial gas reservoirs have been discovered. However, the genesis of these tuffs, revealed by the [...] Read more.

Controversy surrounds the forming time and tectonic background of the Kaijiang–Liangping Trough in the northern Sichuan Basin. The Wuchiapingian Formation, surrounding this Late Permian trough, contains tuffs, and industrial gas reservoirs have been discovered. However, the genesis of these tuffs, revealed by the drilling wells, remains unclear. In the present work, we analyzed the samples of sedimentary tuff from the core of the study area by macroscopic and microscopic analysis, combined with whole-rock major and trace element analysis, zircon U-Pb dating, and zircon trace element analysis, defining the genesis of the Wuchiapingian Formation tuffs around the Kaijiang–Liangping Trough, in an attempt to describe the initial tectonic context of the trough. The U-Pb ages of the tuffs measured in this study range from 255 to 259 Ma. They are slightly later than the activity of the Emeishan Large Igneous Province. Considering the trough’s distance from the center of the Emeishan Large Igneous Province and its location in the outer zone, it is more likely associated with acidic volcanic eruptions of the island arc. The arc was formed by the subduction activity of the Mianlue Ocean beneath the northern Yangtze Plate. In terms of the timing of activity and the tectonic position of the subduction zone, the Kaijiang–Liangping trough in the northern Sichuan Basin is more closely related to the closing of the Mianlue Ocean. Full article

(This article belongs to the Special Issue LA-ICP-MS and LIBS Applied to Minerals)

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1 pages, 127 KiB

Open AccessCorrection

Correction: More et al. Indirect Freeze Crystallization—An Emerging Technology for Valuable Resource Recovery from Wastewater. Minerals 2024, 14, 427

by Kagiso S. More, Johannes P. Maree and Mlungisi Mahlangu

Minerals 2024, 14(10), 1033; https://doi.org/10.3390/min14101033 - 15 Oct 2024

Abstract

Johannes P [...] Full article

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

15 pages, 4721 KiB

Open AccessArticle

The Electrical Properties of Dacite Mixed with Various Pyrite Contents and Its Geophysical Applications for the High-Conductivity Duobaoshan Island Arc

by Mengqi Wang, Tong Sun, Meiling Hong, Ziming Hu, Qichun Yin and Lidong Dai

Minerals 2024, 14(10), 1032; https://doi.org/10.3390/min14101032 - 15 Oct 2024

Abstract

In this work, a series of electrical conductivities of pyrite-bearing dacite were measured under 10⁻¹–10⁶ Hz, 573–973 K, 1.0–3.0 GPa, and different pyrite contents ranging from 0 vol.% to 20 vol.%) using a Solartron–1260 A impedance analyzer. For the dacite [...] Read more.

In this work, a series of electrical conductivities of pyrite-bearing dacite were measured under 10⁻¹–10⁶ Hz, 573–973 K, 1.0–3.0 GPa, and different pyrite contents ranging from 0 vol.% to 20 vol.%) using a Solartron–1260 A impedance analyzer. For the dacite sample with 5 vol.% pyrite, the electrical conductivity of the dacite increased with temperature but slightly decreased when the pressure was increased from 1.0 GPa to 3.0 GPa. In the temperature range of 573–973 K, the bulk electrical conductivity of the pyrite-bearing dacite gradually increased with increasing pyrite percentage from 0 vol.% to 20 vol.% at 1.0 GPa. Thus, a positive correlation between the electrical conductivity of the sample and the pyrite content was typically observed. In light of the significant enhancement in the electrical conductivity of the interconnected pyrite in the dacite, the value of the percolation threshold was determined as 7 vol.%. Furthermore, the dominant conduction mechanism of the small polaron for pyrite-bearing dacite was proposed from our obtained results on the chemical compositions and activation enthalpies under high-temperature and high-pressure conditions. A comprehensive consideration of our constructed electrical conductivity–depth profile based on the electrical conductivity of the pyrite-bearing dacite, can provide a good constraint on the volume of pyrite in dacite for high-conductivity Duobaoshan island arc. In conclusion, the presence of pyrite in dacite can provide a reasonable explanation for the high-conductivity anomaly observed in the region of Duobaoshan island arc. Full article

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

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19 pages, 8741 KiB

Open AccessArticle

Genesis of Xinjiazui Gold Deposit: In Situ Geochemical Constraints from Arsenopyrite

by Ji Liu, Shaolei Kou, Zhanbin Wang, Yixiang Zhang, Yuan Pan, Dongping Ji, Yuan Tian, Hao Chen and Chao Gao

Minerals 2024, 14(10), 1031; https://doi.org/10.3390/min14101031 - 15 Oct 2024

Abstract

The Xinjiazui gold deposit marks a notable significance in prospecting within the Back-Longmenshan tectonic belt, located on the northwest margin of the Yangtze Block, China. Despite the extensive studies conducted on this deposit, the source of the ore-forming materials remains unclear, leading to [...] Read more.

The Xinjiazui gold deposit marks a notable significance in prospecting within the Back-Longmenshan tectonic belt, located on the northwest margin of the Yangtze Block, China. Despite the extensive studies conducted on this deposit, the source of the ore-forming materials remains unclear, leading to ongoing debates regarding the genesis of this deposit. This study analyzed in situ (EPMA and LA-ICP-MS) trace elements and S-Pb isotopes of arsenopyrite, solely from the principal metallogenic stage and paragenetic with native gold. The results show that the gold in arsenopyrite occurs as invisible gold (Au³⁺), with an average concentration of 9.38 ppm, whereas the concentrations of magma-related elements, such as W, Sn, Mo, and Bi, are very low. The sulfur isotopes (³⁴S) of arsenopyrite range from 8.32‰ to 10.16‰, aligning closely with the deep metamorphic basement (Pt₃l). Meanwhile, the lead isotopes in arsenopyrite display characteristics typical of those found in orogenic belts. A comprehensive analysis of the abundance of gold indicated that the metallogenic materials (sulfur and gold) primarily originated from Pt₃l. Additionally, the arsenopyrite thermobarometer indicated that the Xinjiazui gold deposit formed in a medium–low-temperature, medium metallogenic environment (5.57–8.69 km), with a sulfur fugacity (log f (S₂)) below −8.4. Combined with previous research results, this study proposes that the Xinjiazui gold deposit is a subduction-related mesozonal orogenic gold deposit. In gold prospecting and exploration in the Back-Longmenshan tectonic belt, it is essential to focus on the distribution of brittle-ductile shear zones and location of the quartz veins associated with pyrite and arsenopyrite mineralization. Full article

(This article belongs to the Special Issue The Formation and Evolution of Gold Deposits in China)

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15 pages, 3791 KiB

Open AccessArticle

Two-Dimensional Hydration and Triple-Interlayer Lattice Structures in Sulfate-Intercalated Graphene Oxide Nanosheets

by Hae Jun Ahn, Sun Jie Kim, Hyun Goo Kim, Youngho Jee and Seung Hun Huh

Minerals 2024, 14(10), 1030; https://doi.org/10.3390/min14101030 - 14 Oct 2024

Abstract

Sulfate anions (SO₄²⁻) are pivotal in various scientific and industrial domains, including mineralogy, biology, and materials science. While extensive research has elucidated sulfate hydration in bulk solids, liquids, and gaseous clusters, a significant gap persists in understanding sulfate interactions within [...] Read more.

Sulfate anions (SO₄²⁻) are pivotal in various scientific and industrial domains, including mineralogy, biology, and materials science. While extensive research has elucidated sulfate hydration in bulk solids, liquids, and gaseous clusters, a significant gap persists in understanding sulfate interactions within two-dimensional materials, particularly graphene oxide (GO) nanosheets. This study investigates the intricate hydration phenomena and novel triple-interlayer lattice configurations that emerge from sulfate intercalation in GO nanosheets. Utilizing a straightforward methodology for obtaining precise X-ray measurements of confined nanospaces, we analyzed the temperature-dependent behavior and structural characteristics of these systems. Our findings reveal how sulfate ions modulate interlayer spacing, the dynamics of GO layers, and phase transitions. This research offers an atomic-scale understanding of hybrid hydration behaviors within confined SO₄-H₂O nano-environments, advancing our knowledge of sulfate interactions in two-dimensional materials. Full article

(This article belongs to the Special Issue Graphite Minerals and Graphene, 2nd Edition)

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18 pages, 11767 KiB

Open AccessArticle

Aeschynite Group Minerals Are a Potential Recovery Target for Niobium Resources at the Giant Bayan Obo Nb–REE–Fe Deposit in China

by Bo Yang, Li Yang, Yong-Gang Zhao, Guo-Ying Yan, Jian-Yong Liu, Wen-Xiang Meng, Jun-Fang Yu, Lei Chen, Xiao-Chun Li and Xian-Hua Li

Minerals 2024, 14(10), 1029; https://doi.org/10.3390/min14101029 - 14 Oct 2024

Abstract

With the development of the steel industry, China’s demand for niobium is increasing. However, domestic niobium resources are not yet stably supplied and are heavily dependent on imports from abroad (nearly 100%). It is urgent to develop domestic niobium resources. The Bayan Obo [...] Read more.

With the development of the steel industry, China’s demand for niobium is increasing. However, domestic niobium resources are not yet stably supplied and are heavily dependent on imports from abroad (nearly 100%). It is urgent to develop domestic niobium resources. The Bayan Obo deposit is the largest rare earth element deposit in the world and contains a huge amount of niobium resources. However, the niobium resource has not been exploited due to the fine-grained size and heterogeneous and scattered occurrences of Nb minerals. To promote the utilization of niobium resources in the Bayan Obo deposit, we focused on the mineralogical and geochemical characterization of six types of ores and mineral processing samples from the Bayan Obo deposit, using optical microscopes, EPMA, TIMA, and LA–ICP–MS. Our results show that: (1) the niobium mineral compositions are complex, with the main Nb minerals including aeschynite group minerals, columbite–(Fe), fluorcalciopyrochlore, Nb–bearing rutile, baotite, fergusonite–(Y), fersmite, and a small amount of samarskite–(Y). Aeschynite group minerals, columbite–(Fe), and fluorcalciopyrochlore are the main niobium-carrying minerals and should be the primary focus of industrial recycling and utilization. Based on mineralogical and geochemical investigation, the size of the aeschynite group minerals is large enough for mineral processing. Aeschynite group minerals are thus a significant potential recovery target for niobium, as well as for medium–heavy REE resources. The Nb–rich aegirine-type ores with aeschynite group mineral megacrysts are suggested to be the most significant niobium resource for mineral processing and prospecting. Combined with geological features, mining, and mineral processing, niobium beneficiation efforts of aeschynite group minerals are crucial for making breakthroughs in the utilization of niobium resources at the Bayan Obo. Full article

(This article belongs to the Special Issue Mineral Resources in North China Craton)

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