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Minerals, Volume 12, Issue 12 (December 2022) – 159 articles

Cover Story (view full-size image): A series of peralkaline granitic dikes were newly discovered in the Baerzhe area, NE China, which can be divided into rhyolite, granite porphyry and miarolitic granite. The rhyolite dikes exhibit a spherulite structure which is composed of K-feldspar and sodic amphibole. These dikes are centered on Baerzhe peralkaline granite and intruded at a higher altitude in NE-NNE trending. The glomeroporphyritic aggregates developed in these dikes, which have a similar mineral composition to the Baerzhe granite and are considered the physical accumulation of minerals. Our study shows that the Baerzhe barren granite is the residual mineral phases remaining as plutons, and the peralkaline rhyolite dikes represent more evolved interstitial melts, both of which are derived from the same magma chamber. View this paper
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10 pages, 2372 KiB  
Article
Spinodal Decomposition in Natural Bornite–Chalcopyrite Intergrowths: A Way of Cu-(Fe)-Sulfide Mineral Growth
by Rui Liu, Lei Zuo, Peng Zhang, Dongping Tao, Huaizhi Shao, Gang Tao and Kun Wang
Minerals 2022, 12(12), 1636; https://doi.org/10.3390/min12121636 - 19 Dec 2022
Cited by 1 | Viewed by 1167
Abstract
Spinodal decomposition is an important mechanism of exsolution. However, spinodal decomposition has not been observed in natural sulfide intergrowths. We utilized focused ion beam (FIB) and transmission electron microscopy (TEM) techniques to confirm spinodal decomposition in natural sulfide intergrowths (chalcopyrite and bornite). According [...] Read more.
Spinodal decomposition is an important mechanism of exsolution. However, spinodal decomposition has not been observed in natural sulfide intergrowths. We utilized focused ion beam (FIB) and transmission electron microscopy (TEM) techniques to confirm spinodal decomposition in natural sulfide intergrowths (chalcopyrite and bornite). According to FIB and TEM analyses, spinodal decomposition occurred as small and curving alternating dark and bright fluctuations in natural bornite–chalcopyrite intergrowths. Due to the low temperature that drove the exsolution mechanism, fluctuations ~10 nm wide and 20–200 nm long contained non-stoichiometric and tetragonal bornite and chalcopyrite. The corresponding electron diffraction of spinodal decomposition displayed a satellite spot in the [−210] direction for bornite, and the (200)* and (224)* of chalcopyrite paralleled the (24−2)* and (242)* of bornite, respectively. These observations all agreed with spinodal decomposition, two coexisting phases formed with a crystallographic orientation relationship, which indicated the first observation of spinodal decomposition in natural sulfide intergrowths. These findings confirmed that spinodal decomposition is a mechanism for natural crystal growth. As spinodal decomposition is larger in extent and faster than nucleation and growth, other Cu ore deposits may also form via this mechanism. Full article
(This article belongs to the Section Mineral Deposits)
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20 pages, 4399 KiB  
Article
Systematic Evaluation for the Impact of the Geological Conditions on the Adsorption Affinities of Calcite as an Adsorbent of Zn2+ Ions from Aqueous Solutions: Experimental and Theoretical Studies
by Nourhan Nasser, Mohamed I. El-Sayed, Sarah I. Othman, Ahmed A. Allam, Ibrahim G. Al-Labadi, Mostafa R. Abukhadra and Stefano Bellucci
Minerals 2022, 12(12), 1635; https://doi.org/10.3390/min12121635 - 19 Dec 2022
Cited by 3 | Viewed by 1292
Abstract
Three samples of calcite (calcite crystal (CA), calcite of limestone (L.CA), and metamorphosed calcite (marble) (M.CA)) were assessed as adsorbents of Zn (II) to consider the impact of the different geological conditions. The three samples exhibit remarkable changes in their Zn (II) retention [...] Read more.
Three samples of calcite (calcite crystal (CA), calcite of limestone (L.CA), and metamorphosed calcite (marble) (M.CA)) were assessed as adsorbents of Zn (II) to consider the impact of the different geological conditions. The three samples exhibit remarkable changes in their Zn (II) retention capacities (Qsat = 384.6 mg/g (CA), 274.5 mg/g (L.CA), and 512.6 mg/g (M.CA)). The retention systems of the three calcite samples were described on the basis of the suggested statistical physics-based equilibrium studies as well as the traditional kinetic and isotherm models. However, the M.CA samples exhibited the best retention capacity, the steric properties reflecting a higher active site density of CA (Nm (Zn) = 113.46 mg/g) than both M.CA (Nm (Zn) = 82.8 mg/g) and L.CA (Nm (Zn) = 52.4 mg/g) at 323 K. This was assigned to the controlling effect of the sequestered numbers of Zn (II) per site on the surfaces of the calcite phase (n(Zn) = 3.39 (CA), 5.24 (L.CA), and 6.19 (M.CA)) in addition to the higher surface area and ion exchange of the metamorphosed and deformed M.CA. The previous n(Zn) values suggested the retention of Zn (II) by a multi-ionic mechanism in a vertical orientation. The Gaussian energies (8 to 16 KJ/mol) and retention energies (˂40 KJ/mol) of Zn (II) by CA and L.CA suggested complex physical and weak chemical mechanisms involving ion exchange, hydrogen bonding, dipole bonding forces, electrostatic attractions, and van der Waals forces. The thermodynamic properties were illustrated on the basis of the internal energy, free enthalpy, and entropy functions, which validate the endothermic and spontaneous nature of the Zn (II) retention system by the three calcite samples. Full article
(This article belongs to the Special Issue Sulphate and Carbonate Minerals)
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20 pages, 3066 KiB  
Article
Selective Neodymium Enrichment of Sulfides as a “Fingerprint” of Late Processes of Ore-Formation: Insight into Sm-Nd Isotopes for Sulfides from Magmatic Cu-Ni-PGE Complexes and Hydrothermal Pb-Zn, Au-Mo, and Gold Deposits
by Pavel A. Serov
Minerals 2022, 12(12), 1634; https://doi.org/10.3390/min12121634 - 19 Dec 2022
Viewed by 1111
Abstract
The effect of enrichment with Nd in sulfides from magmatic Cu-Ni-PGE complexes and sulfide ores from hydrothermal Pb-Zn, Au-Mo, and gold deposits was found and characterized. This paper concerns the report and analysis of isotopic geochemical data on the sulfide ores from the [...] Read more.
The effect of enrichment with Nd in sulfides from magmatic Cu-Ni-PGE complexes and sulfide ores from hydrothermal Pb-Zn, Au-Mo, and gold deposits was found and characterized. This paper concerns the report and analysis of isotopic geochemical data on the sulfide ores from the large Paleoproterozoic mafic–ultramafic magmatic Cu-Ni-PGE complexes of Fennoscandia and the literature data on sulfide ores from the Qingchengzi Pb-Zn deposit (northeastern China), Tokuzbay gold deposit (southern Altai, northwestern China), and Dahu Au-Mo deposit (central China). The mineral/rock partition coefficients for Nd and Sm (the DNd/DSm ratio) are defined as a prospective tool for the reconstruction of the sulfide mineral formation and geochemical substantiation of possible sources of ore-forming fluids for deposits of various genetic types. The observed selective Nd accumulation indicates either hydrothermal or metamorphic (metasomatic) impact, which is associated with increased Nd mobility and its migration or diffusion. Due to this process, there is a relative Nd accumulation in comparison with Sm and a consequent increase in the DNd/DSm ratio. At the isotopic system level, this leads to a sufficient decrease in the Sm/Nd ratio for the secondary sulfides of such kind. The revealed effect may serve as an isotopic geochemical marker of recent processes. These processes are quite frequently associated with the most important ore formation stages, which bear the commercially valuable concentrations of ore components. Sulfides from magmatic Cu-Ni-PGE complexes are more characterized by the selective accumulation of Nd in the sequential sulfide mineral formation. For sulfides from hydrothermal deposits, the effect of Nd enrichment is more intense and closely related to ore-forming fluids, under the influence of which sulfide mineralization is formed in multiple stages. The study aims at expanding the knowledge about fractionation and the behavior of lanthanides in ore-forming processes and allows the development of additional criteria for the evaluation of the ore potential of deposits with different geneses, ages, and formation conditions. Full article
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15 pages, 4465 KiB  
Article
Selective Flotation Behavior of Dolomite from Fluorapatite Using Hydroxy Ethylene Diphosphonic Acid as High-Efficiency Depressant
by Jingkun Zhang, Zhiyun Xiao and Hongbo Zhang
Minerals 2022, 12(12), 1633; https://doi.org/10.3390/min12121633 - 19 Dec 2022
Cited by 2 | Viewed by 1326
Abstract
In the reverse flotation of fluorapatite and dolomite, high-efficiency depressors of fluorapatite have received considerable attention. In this paper, the depression mechanism of hydroxy ethylene diphosphonic acid (HEDP) was studied for the first time as a novel fluorapatite depressant on the surface of [...] Read more.
In the reverse flotation of fluorapatite and dolomite, high-efficiency depressors of fluorapatite have received considerable attention. In this paper, the depression mechanism of hydroxy ethylene diphosphonic acid (HEDP) was studied for the first time as a novel fluorapatite depressant on the surface of fluorapatite. The effect of HEDP on the flotation behavior of the two minerals was studied by single and mixed minerals in flotation tests. HEDP exhibited an excellent depression effect on fluorapatite flotation, whereas its adsorption on dolomite surface was minimal. Fluorapatite and dolomite were effectively separated by applying sodium oleate as a collector and HEDP as a depressant at pH 6.0. The depression mechanism of HEDP on fluorapatite was further analyzed via contact angle measurement, zeta potential and X-ray photoelectron spectroscopic (XPS) analysis. We found that HEDP seriously hindered the adsorption of sodium oleate (NaOL) on the fluorapatite surface and had a minimal effect on the dolomite surface. XPS analysis results indicate that the strong adsorption of HEDP on the fluorapatite surface can be attributed to the strong chelation between the electron-rich groups of HEDP and Ca ions on the fluorapatite surface. Therefore, HEDP is used as a selective depressant of fluorapatite in the fluorapatite–dolomite flotation–separation process. Full article
(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
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27 pages, 6327 KiB  
Article
Paleogeographic Evolution of Southeast Asia: Geochemistry and Geochronology of the Katha-Gangaw Range, Northern Myanmar
by Myo Myint Aung, Lin Ding, Upendra Baral, Fulong Cai, Bhupati Neupane, Me Me Aung, Aung Naing Thu, Kyaing Sein and Kyawt Kay Khaing
Minerals 2022, 12(12), 1632; https://doi.org/10.3390/min12121632 - 18 Dec 2022
Cited by 2 | Viewed by 1990
Abstract
The Mogok continental foreland region and Katha-Gangaw range (KGR) are located in the north-central section of the Myanmar plate, which is a component of the Eurasian plate. The origin of KGR, exposed along northern Myanmar (SE Asia), is still up for argument, despite [...] Read more.
The Mogok continental foreland region and Katha-Gangaw range (KGR) are located in the north-central section of the Myanmar plate, which is a component of the Eurasian plate. The origin of KGR, exposed along northern Myanmar (SE Asia), is still up for argument, despite numerous prior studies. Based on the petrography, geochemistry, and detrital zircon U-Pb geochronology of metamorphic rock samples, the current study focuses on the tectonic evolution of the KGR. The study also emphasizes the phenomenon of microcontinents rifting from the Gondwanan supercontinent and their subsequent amalgamation with Asia. Detrital zircon ages from four samples in the southern region of KGR peak at 634 Ma, 525 Ma, 290 Ma, and 248 Ma, and two samples yielded > 40% of the grains of younger than 400 Ma. Similar results were obtained from three samples (out of six) from the central region of the KGR. All of the samples from the northern part of KGR are older than 400 Ma, with the exception of MT-02A, which contains nearly all of the younger grains. These younger peaks are identical to the zircon U-Pb ages of the Indochina block, the Sibumasu block, and the Pane Chaung Formation of the Myanmar plate, as well as the Langjiexue Formation (southeastern Tibet). This similarity raises the possibility of either these units being a source region of strata in northern Myanmar or sharing a similar source. The geochemistry of metamorphic rocks samples from KGR revealed loss-on-ignition (LOI) values of 0.29–4.18 wt%, emphasizing the modest to moderate alteration. The samples are enriched in large-ion lithophile elements (LILEs), and depleted in high-field strength elements (HFSEs). All metamorphic samples are peraluminous, indicating the linkage with collisional orogenies. This result is most comparable to upper continental crustal provenance. Hence, the metamorphic rocks in KGR regions must be associated with the crustal materials. Full article
(This article belongs to the Special Issue Applications of U-Th-Pb Geochronology of Accessory Minerals)
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18 pages, 3222 KiB  
Article
Biogeofilter with Hydrothermal Treated Stevensite Clay and Laccase Enzymes for Retention and Degradation of Tetracycline
by Adrien Saphy, María Tijero, Carlos García-Delgado, Almudena Ortega, Sergio Zamora, Ana Isabel Ruiz, Enrique Eymar, Jaime Cuevas and Raúl Fernández
Minerals 2022, 12(12), 1631; https://doi.org/10.3390/min12121631 - 17 Dec 2022
Cited by 1 | Viewed by 1509
Abstract
The concentration of antibiotics in surface water is an issue of high concern. The present study aims to manufacture and evaluate a biogeofilter, with stevensite clay and enzymes immobilized on it, for the adsorption and degradation of tetracycline-based antibiotics. To retain the small [...] Read more.
The concentration of antibiotics in surface water is an issue of high concern. The present study aims to manufacture and evaluate a biogeofilter, with stevensite clay and enzymes immobilized on it, for the adsorption and degradation of tetracycline-based antibiotics. To retain the small particle aggregates of the clay in the filter, a hydrothermal treatment was applied to the stevensite, prior to compaction in pellets and its insertion into a cylindric cell, mixed with sand. The structure of the pellets avoids the loss of the clay material during the fluid transport through the porous medium. Several temperature treatments were applied to the pellets, but the treatment at 300 °C was revealed as the best option. Laccase enzymes were immobilized on the stevensite surface. Reactive transport experiments of tetracycline solutions were performed through the transport cells. The biogeofilter has a relevant adsorption capacity with a significant degradation factor. By modelling with STANMOD software, the hydrodynamic characteristics of the transport were determined and, therefore, the behaviour of a large-scale filter and transports of low tetracycline concentrations could be predicted. The results obtained are promising for irrigation systems at medium scale, as well as for the perspective of wastewater treatment plants at large scale. Full article
(This article belongs to the Section Clays and Engineered Mineral Materials)
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14 pages, 2948 KiB  
Article
Elemental Gains and Losses during Hydrothermal Alteration in Awak Mas Gold Deposit, Sulawesi Island, Indonesia: Constraints from Balanced Mineral Reactions
by Ernowo Ernowo, Arifudin Idrus and Franz Michael Meyer
Minerals 2022, 12(12), 1630; https://doi.org/10.3390/min12121630 - 17 Dec 2022
Cited by 1 | Viewed by 1425
Abstract
Hydrothermal gold mineralization is commonly associated with metasomatic processes resulting from interaction of hostrock with infiltrating hot aqueous fluids. Understanding of the alteration mechanism requires quantification of element changes in altered rock, relative to the unaltered or least-altered rock, representing the protolith. Balanced [...] Read more.
Hydrothermal gold mineralization is commonly associated with metasomatic processes resulting from interaction of hostrock with infiltrating hot aqueous fluids. Understanding of the alteration mechanism requires quantification of element changes in altered rock, relative to the unaltered or least-altered rock, representing the protolith. Balanced mineral reactions are used to gain quantitative insight into the alteration process associated with gold mineralization at the Awak Mas deposit. Three representative samples were carefully selected from the least-altered pyllite and the two alteration zones bordering the mineralization. Mineral mode, textural features, and mineral compositions were studied by microscopy and electron microprobe analyzer (EMPA). Quantitative modal analysis was performed with a Quanta 650 F QEMSCAN® system. The hydrothermal alteration sequence around the mineralization starts with the proximal albite–ankerite–pyrite alteration zone via the distal albite–chlorite alteration zone to the least-altered phyllite wall-rock. Balanced mineral reaction calculations were performed to evaluate elemental gains and losses. Most noticeable is the addition of Si, Na and Ca to each alteration zone. This alteration is represented by the almost complete replacement of muscovite by albite. The addition of Fe and S was highest in the albite–ankerite–pyrite alteration zone. Alteration of the least altered phyllite to the albite–chlorite zone involved a mass increase of 14.5% and a neglectable volume increase of 0.6%. The mass and a volume increase from the least altered phyllite to the albite–ankerite–pyrite zone was 40.5% and 0.47%, respectively. The very low volume change during alteration is also corroborated by the textural preservation indicating isovolumetric metasomatic reactions. The replacement of muscovite by albite may have had an important effect on the change of the rock failure mode from ductile to brittle, with consequences for the focusing of fluid flow. Full article
(This article belongs to the Special Issue Economic Mineral Deposits: A Review)
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23 pages, 60457 KiB  
Article
Multi-Dimensional Data Fusion for Mineral Prospectivity Mapping (MPM) Using Fuzzy-AHP Decision-Making Method, Kodegan-Basiran Region, East Iran
by Ali Shabani, Mansour Ziaii, Mehrdad Solimani Monfared, Adel Shirazy and Aref Shirazi
Minerals 2022, 12(12), 1629; https://doi.org/10.3390/min12121629 - 17 Dec 2022
Cited by 9 | Viewed by 1764
Abstract
Analyzing and fusing information layers of exploratory parameters is a crucial stride for increasing the accuracy of pinpointing mineral potential zones in the reconnaissance stage of mineral exploration. Remote sensing, geophysical, geochemical, and geology data were analyzed and fused for identify metallic mineralization [...] Read more.
Analyzing and fusing information layers of exploratory parameters is a crucial stride for increasing the accuracy of pinpointing mineral potential zones in the reconnaissance stage of mineral exploration. Remote sensing, geophysical, geochemical, and geology data were analyzed and fused for identify metallic mineralization in the Kodegan-Basiran region (East Iran). Landsat 7 Enhanced Thematic Mapper Plus (ETM+), aeromagnetic data, geological data, and geochemical stream sediment samples were utilized. The study area contains some copper indices and mines. Thus, the main focus of this study was identifying the zones with high potential for metallic copper mineralization. A two-stage methodology was implemented in this study: First, extraction of the exploratory parameters related to metallic mineralization and second is data fusion by the hybrid fuzzy-analytic hierarchy process (Fuzzy-AHP) method. Hydrothermal alterations and iron oxides in the area were mapped by applying the optimum index factor (OIF), band ratio (BR), and least squared fit (LS-Fit) to ETM+ data. Intrusive masses were positioned as one of the effective parameters in identifying metallic mineralization zones using the gradient tensor method to assess aeromagnetic data. In order to determine the threshold concentration and the location of mineralization anomalies, the K-means clustering algorithm, vertical geochemical zonality (Vz) index, as well as concentration-area (C-A) multi fractal and singularity analysis were implemented on the geochemical data. In conclusion, the potential zones of metallic mineralization in the Kodegan-Basiran region were displayed in a mineral prospectivity map (MPM) derived from the Fuzzy-AHP decision-making method. Finally, to validate the prospectivity map of metallic mineralization, a control area was selected and surveyed by collecting mineralogical, petrological, and stream sediment samples. Field works confirmed the mineralization of Cu and Fe sulfides, oxides, and hydroxides. The high potential areas identified in the MPM can be considered as targets for future Cu exploration in the Kodegan-Basiran area. Full article
(This article belongs to the Special Issue AI-Based GIS for Pinpointing Mineral Deposits)
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38 pages, 8478 KiB  
Review
Ion Exchange in Natural Clinoptilolite: Aspects Related to Its Structure and Applications
by Inocente Rodríguez-Iznaga, Marina G. Shelyapina and Vitalii Petranovskii
Minerals 2022, 12(12), 1628; https://doi.org/10.3390/min12121628 - 17 Dec 2022
Cited by 13 | Viewed by 2165
Abstract
Clinoptilolite is one of the most common, widespread and abundant zeolites in nature. Its availability, low cost, and outstanding ion exchange properties make clinoptilolite an excellent candidate for both direct use and various modifications to create new low-cost functional materials for sustainable development. [...] Read more.
Clinoptilolite is one of the most common, widespread and abundant zeolites in nature. Its availability, low cost, and outstanding ion exchange properties make clinoptilolite an excellent candidate for both direct use and various modifications to create new low-cost functional materials for sustainable development. Specific applications in which clinoptilolite is already being used include water treatment and heavy metal ion removal, agricultural purposes, storage and conversion of unwanted gaseous emissions into the atmosphere, production of catalysts and photocatalysts, bioactive materials, and a number of others. Unlike some other zeolites, clinoptilolite is difficult to synthesize, which is why most publications refer to this zeolite in its natural form, either directly from the deposit or after applying various processes to this mineral to improve its properties. Among the modification methods used, ion exchange stands out. This review is devoted to the study of ion exchange processes in natural clinoptilolite with two goals: first, as its strategic property for use in processes in which cation exchange is fundamentally necessary; second, as a way to modify it to create composite materials with predetermined desired properties. Full article
(This article belongs to the Special Issue Structural Study on Ion Exchange Process of Clinoptilolite)
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29 pages, 4216 KiB  
Article
Calcium Carbonate Hexahydrate (Ikaite): History of Mineral Formation as Recorded by Stable Isotopes
by Michael J. Whiticar, Erwin Suess, Gerold Wefer and Peter J. Müller
Minerals 2022, 12(12), 1627; https://doi.org/10.3390/min12121627 - 17 Dec 2022
Cited by 5 | Viewed by 1781
Abstract
Calcium carbonate hexahydrate (ikaite) is a rare mineral that forms as metastable species in the organic-carbon-rich sediments of the King George Basin, Bransfield Strait, Antarctica, as a consequence of early diagenetic decomposition of organic matter under cold water (−1.4 °C) and high pressure [...] Read more.
Calcium carbonate hexahydrate (ikaite) is a rare mineral that forms as metastable species in the organic-carbon-rich sediments of the King George Basin, Bransfield Strait, Antarctica, as a consequence of early diagenetic decomposition of organic matter under cold water (−1.4 °C) and high pressure (200 bar) conditions. Large crystals grow in the sediment immediately below the diagenetic transition between microbial sulfate reduction and methanogenesis at ~320 cm below sea floor (bsf). This process is reflected in the dissolved sulfate, total carbon dioxide, and methane concentrations, as well as in the carbon, hydrogen, and oxygen isotope chemistries of the interstitial fluids and dissolved gases of the host sediment. The ikaite crystal faithfully records in its zonal structure the changing carbon isotope ratio of the total dissolved carbon dioxide pool as it gradually diminishes during methanogenesis (δ13Cikaite = −17.5 to −21.4‰). These changes in the crystal’s host environment follow general Rayleigh carbon isotope fractionation. The oxygen isotopes of the ikaite carbonate (δ18Oikaite = 1.46 to 4.45‰) also show a strong zonal distribution, unrelated to temperature of formation, but perhaps controlled by the degree of recrystallization of ikaite to calcite. The crystal water of the ikaite is depleted 11‰ in 2H/1H (VSMOW) relative to the coexisting interstitial water, which is in excellent agreement with the isotope fractionation of other hydrated minerals. In addition to the in situ temperature and pressure, nucleation of the ikaite crystals in the Bransfield Basin sediments may be induced by the high alkalinity, high phosphate concentrations, and dissolved organic compounds. Intense microbial metabolism generates such compounds; of these, aspartic acid and glutamic acid may play an important role, as they do in biological and extracellular carbonate mineral precipitation. All indications are that low temperatures (such as of polar environments), high calcium carbonate supersaturation caused by interstitial methanogenesis, and a sufficiently large supply of dissolved phosphate and amino acids favor metastable ikaite formation. These conditions, modified by recrystallization, may be preserved in calcite glendonites, thinolites, and other calcitic pseudomorphs derived from ikaite and found throughout the ancient sedimentary record. Full article
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40 pages, 11268 KiB  
Article
The Heavy-Metal Fingerprint of the Irinovskoe Hydrothermal Sulfide Field, 13°20′ N, Mid-Atlantic Ridge
by Irina Melekestseva, Vasiliy Kotlyarov, Gennadiy Tret’yakov, Vladimir Shilovskikh, Pavel Khvorov, Elena Belogub, Victor Beltenev, Kseniya Filippova and Sergey Sadykov
Minerals 2022, 12(12), 1626; https://doi.org/10.3390/min12121626 - 16 Dec 2022
Cited by 1 | Viewed by 2273
Abstract
A number of Cd-, Pb-, Ag- and Sb(±As)-bearing minerals are found in the Zn-rich smoker chimneys of the Irinovskoe hydrothermal sulfide field, 13°20′ N, Mid-Atlantic Ridge. Sulfide samples were studied using optical microscopy, SEM/EDS, XRD, EBDS, ICP-MS and thermodynamic approaches. The chimneys consist [...] Read more.
A number of Cd-, Pb-, Ag- and Sb(±As)-bearing minerals are found in the Zn-rich smoker chimneys of the Irinovskoe hydrothermal sulfide field, 13°20′ N, Mid-Atlantic Ridge. Sulfide samples were studied using optical microscopy, SEM/EDS, XRD, EBDS, ICP-MS and thermodynamic approaches. The chimneys consist of major sphalerite (including Cd-bearing type with up to 41.38 wt% Cd) and wurtzite, subordinate opal, pyrite, chalcopyrite and Fe-oxyhydroxides, as well as accessory native sulfur, baryte, secondary copper sulfides, galena, CdS phase (most likely hawleyite), pyrrhotite, isocubanite, acanthite, Ag–Cu–Sb(±As)-bearing minerals, native gold, anglesite, gypsum, smectites, naumannite and lollingite. The main source of metals for the formation of Zn-rich sulfides was mafic rocks, with a subordinate role from ultramafic rocks. Crystallization of most accessory minerals at low temperatures (<120 °C) under acidic/reducing conditions and low S activity could be initiated by a magmatic input, which is supported by a negative S isotopic composition of bulk sulfide samples. The finding of Cd-rich sphalerite and a CdS phase in low-temperature mineral assemblage significantly expands the temperature limits of their possible formation. The high Cd contents of easily soluble sphalerite and the presence of the CdS phase should be taken into account in possible future mining and processing of seafloor hydrothermal sulfide fields. Full article
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2 pages, 194 KiB  
Editorial
Editorial for Special Issue “Mantle Strain Localization—How Minerals Deform at Deep Plate Interfaces”
by Jacques Précigout, Cécile Prigent and Bjarne Almqvist
Minerals 2022, 12(12), 1625; https://doi.org/10.3390/min12121625 - 16 Dec 2022
Viewed by 808
Abstract
Understanding Earth’s interior dynamics, the origin and factors of which maintain the present-day plate-like behavior of the lithosphere on our planet, is one of the main goals of geosciences [...] Full article
16 pages, 9091 KiB  
Article
Study on the Improved Method for Calculating Traveltime and Raypath of Multistage Fast Marching Method
by Qiong Wu, Hong-Ze Mi, Yong-Bo Li and Yan-Gui Li
Minerals 2022, 12(12), 1624; https://doi.org/10.3390/min12121624 - 16 Dec 2022
Viewed by 997
Abstract
The traditional Fast Marching Method (FMM) based on the finite-difference scheme can solve the traveltime of first arrivals; however, the accuracy and efficiency of FMM are usually affected by the finite-difference schemes and grid size. The Vidale finite-difference scheme and double-grid technology are [...] Read more.
The traditional Fast Marching Method (FMM) based on the finite-difference scheme can solve the traveltime of first arrivals; however, the accuracy and efficiency of FMM are usually affected by the finite-difference schemes and grid size. The Vidale finite-difference scheme and double-grid technology are adopted to replace the traditional first-order and second-order finite-difference schemes in this paper to improve the computation accuracy and efficiency. The traditional FMM does not provide the corresponding raypath calculation methods, and in view of the interoperability of FMM and the linear travel time interpolation (LTI) method, we introduce the linear interpolation method into FMM ray tracing to compute the raypath and take into consideration the secondary source located inside the grid cell to improve the accuracy and stability of the raypath calculation. With these measures and the application of the multistage approach, we successfully completed the improved Multistage FMM (MFMM) ray tracing, which can track first arrivals and any type of primary and multiple reflection waves. Through the theoretical and actual field model tests, the computation accuracy and efficiency of the improved MFMM are proven to be higher than that under traditional first-order and second-order finite-difference schemes, the correctness and effectiveness of the interpolation method for raypath calculation are verified, and the improved MFMM has demonstrated good adaptability and stability for complex models. The improvements for the MFMM in this paper are successfully applied in two-dimensional cases and need to be extended to three-dimensional situations. Full article
(This article belongs to the Special Issue Theory and Applications of Seismic Inversion)
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15 pages, 4119 KiB  
Article
Hydrodynamic Hysteresis and Solute Transport in Agglomerated Heaps under Irrigation, Stacking, and Bioleaching Controlling
by Leiming Wang, Shenghua Yin, Xuelan Zhang, Zepeng Yan and Wensheng Liao
Minerals 2022, 12(12), 1623; https://doi.org/10.3390/min12121623 - 16 Dec 2022
Cited by 4 | Viewed by 1130
Abstract
Hydrodynamic hysteresis exists widely in agglomerated heaps with well-developed intra-pores, and it directly affects solute transports and bioleaching reaction. In this paper, the dynamic liquid retention behavior under different heap porosity and irrigation condition is quantified via a novel real-time, in-situ liquid retention [...] Read more.
Hydrodynamic hysteresis exists widely in agglomerated heaps with well-developed intra-pores, and it directly affects solute transports and bioleaching reaction. In this paper, the dynamic liquid retention behavior under different heap porosity and irrigation condition is quantified via a novel real-time, in-situ liquid retention characterizing system (RILRCS), and the potential effects of initial liquid retention on solute transport and leaching reaction are carefully discussed. The results show that the immobile liquid is dominant in agglomerated heaps. The ratio of immobile and mobile liquid (η) dynamically changes due to mineral dissolution and new flow path appearances. The η normally increases and mobile liquid occupies a higher proportion due to acidic leaching reactions, especially at a smaller Rg (10.32 mm) and a larger u (0.10 mm/s). The dynamic liquid retention is more sensitive to the diameter of packed feeds (Rg) and superficial flow rate (u) instead of leaching reactions. This might be because the damage of leaching reaction on minerals pores/voids is limited and cannot extensively change the potential pore channels or fluid flow paths. Based on pulse tracing and conductivity tests, we reveal that the solute resides longer under a slower u and smaller packed Rg condition, which corresponds well with desirable copper leaching efficiency. Specifically, the liquid hysteresis behavior is more obvious at a lower u (0.01 mm/s) and smaller Rg (10.32 mm). This paper gives a good reference to ascertain the liquid retention and hydrodynamic hysteresis and promote mineral leaching performance. Full article
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14 pages, 3326 KiB  
Article
Research on the Homogenization Evaluation of Cemented Paste Backfill in the Preparation Process Based on Image Texture Features
by Liuhua Yang, Jincang Li, Huazhe Jiao, Aixiang Wu and Shenghua Yin
Minerals 2022, 12(12), 1622; https://doi.org/10.3390/min12121622 - 16 Dec 2022
Cited by 11 | Viewed by 1067
Abstract
In China, cemented paste backfill (CPB) is a common treatment method after the exploitation of basic energy. The homogeneity of slurry influences the performance of CPB. However, the online monitoring and characterization of homogeneity lack relevant technologies and unified standards. This article discusses [...] Read more.
In China, cemented paste backfill (CPB) is a common treatment method after the exploitation of basic energy. The homogeneity of slurry influences the performance of CPB. However, the online monitoring and characterization of homogeneity lack relevant technologies and unified standards. This article discusses an online image analysis technique applied to the online monitoring of cemented paste backfill mixing, which is based on the evolution of the texture of images taken at the surface of the mixing bed. First, the grayscale distribution of the image obtained by the high-speed camera in the CPB preparation process was analyzed by Matlab and its variance (s2) was solved, and the texture features of the image were analyzed by the variance of grayscale distribution. Then, a homogeneity discriminant model (cst) was established. The results show that the variance value of the grayscale distribution of the slurry image increases rapidly at first, then gradually decreases, and becomes stable in the final stage since it turns a constant value. When the s2 value tends to be stable, the slurry gradually reaches homogenization, and the discriminant coefficient of paste homogenization based on the homogenization discriminant model reaches 0.05. The homogenization prediction of CPB proves to be consistent with the backfill performance comparison results. The evolution of the texture allows obtaining important information on the evolution of different formulations during mixing, which can be used for intelligent monitoring of CPB preparation process. Full article
(This article belongs to the Special Issue Cemented Mine Waste Backfill: Experiment and Modelling)
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25 pages, 5892 KiB  
Article
Automated Hyperparameter Optimization of Gradient Boosting Decision Tree Approach for Gold Mineral Prospectivity Mapping in the Xiong’ershan Area
by Mingjing Fan, Keyan Xiao, Li Sun, Shuai Zhang and Yang Xu
Minerals 2022, 12(12), 1621; https://doi.org/10.3390/min12121621 - 16 Dec 2022
Cited by 2 | Viewed by 2003
Abstract
The weak classifier ensemble algorithms based on the decision tree model, mainly include bagging (e.g., fandom forest-RF) and boosting (e.g., gradient boosting decision tree, eXtreme gradient boosting), the former reduces the variance for the overall generalization error reduction while the latter focuses on [...] Read more.
The weak classifier ensemble algorithms based on the decision tree model, mainly include bagging (e.g., fandom forest-RF) and boosting (e.g., gradient boosting decision tree, eXtreme gradient boosting), the former reduces the variance for the overall generalization error reduction while the latter focuses on reducing the overall bias to that end. Because of its straightforward idea, it is prevalent in MPM (mineral prospectivity mapping). However, an inevitable problem in the application of such methods is the hyperparameters tuning which is a laborious and time-consuming task. The selection of hyperparameters suitable for a specific task is worth investigating. In this paper, a tree Parzen estimator-based GBDT (gradient boosting decision tree) model (TPE-GBDT) was introduced for hyperparameters tuning (e.g., loss criterion, n_estimators, learning_rate, max_features, subsample, max_depth, min_impurity_decrease). Then, the geological data of the gold deposit in the Xiong ‘ershan area was used to create training data for MPM and to compare the TPE-GBDT and random search-GBDT training results. Results showed that the TPE-GBDT model can obtain higher accuracy than random search-GBDT in a shorter time for the same parameter space, which proves that this algorithm is superior to random search in principle and more suitable for complex hyperparametric tuning. Subsequently, the validation measures, five-fold cross-validation, confusion matrix and success rate curves were employed to evaluate the overall performance of the hyperparameter optimization models. The results showed good scores for the predictive models. Finally, according to the maximum Youden index as the threshold to divide metallogenic potential areas and non-prospective areas, the high metallogenic prospect area (accounts for 10.22% of the total study area) derived by the TPE-GBDT model contained > 90% of the known deposits and provided a preferred range for future exploration work. Full article
(This article belongs to the Special Issue Genesis and Metallogeny of Non-ferrous and Precious Metal Deposits)
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17 pages, 11798 KiB  
Article
Strengthening Gold Extraction from Carbonaceous Gold Ore Based on Decarburization by Two-Stage Fluidized Oxidation Roasting
by Hanxin Xiao, Jianping Jin, Fayu He, Yuexin Han and Yongsheng Sun
Minerals 2022, 12(12), 1620; https://doi.org/10.3390/min12121620 - 16 Dec 2022
Cited by 2 | Viewed by 1572
Abstract
Oxidation roasting is one of the most effective methods to remove carbonaceous matter from carbonaceous gold ore. However, the consolidation of calcine is a common problem caused by a large amount of heat release during the oxidation roasting of gold ore with high [...] Read more.
Oxidation roasting is one of the most effective methods to remove carbonaceous matter from carbonaceous gold ore. However, the consolidation of calcine is a common problem caused by a large amount of heat release during the oxidation roasting of gold ore with high carbon and sulfur content. In this study, a two-stage fluidized oxidation roasting method was developed to strengthen gold extraction. Pre-roasting was performed in a low oxygen environment for the mild combustion of carbonaceous matter, and then the pre-roasted product was subjected to secondary roasting followed by leaching. The results show that reducing the carbon content in the ore by pre-roasting can effectively lower the peak temperature inside the material. After the second-stage roasting, many cracks and pores were formed in silicates and carbonates, thus increasing the distribution of exposed gold from 28.95% to 88.01%. Finally, the extraction of gold increased from 4.55% to 86.10%. Overall, this study provides references for an efficient strategy for gold recovery from carbonaceous gold ores. Full article
(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
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15 pages, 3877 KiB  
Article
Are Coal-Hosted Gallium-Rich Ores Elastically Detectable: A Rock-Physics Modeling Perspective
by Tongjun Chen and Xiong Song
Minerals 2022, 12(12), 1619; https://doi.org/10.3390/min12121619 - 15 Dec 2022
Cited by 2 | Viewed by 1238
Abstract
Coal-hosted gallium-rich ores are mainly explored with geochemical analyses, and their elasticities lack research. This paper incorporated core testing, rock-physics modeling, and Monte Carlo simulations to characterize the elastic parameters of gallium-rich cores and discuss whether coal-hosted gallium-rich ores are elastically detectable. The [...] Read more.
Coal-hosted gallium-rich ores are mainly explored with geochemical analyses, and their elasticities lack research. This paper incorporated core testing, rock-physics modeling, and Monte Carlo simulations to characterize the elastic parameters of gallium-rich cores and discuss whether coal-hosted gallium-rich ores are elastically detectable. The measured cores from No. 6 coal in the Heidaigou mine showed that the gallium contents strongly correlate to the boehmite contents with a 0.96 correlation coefficient. The rock-physics modeling results showed that mineral compositions and contents are critical factors influencing elastic parameters, and elastic parameters in No. 6 coal showed profound heterogeneities as mineral compositions and contents. The preferred parameters for classifying and grouping different mineral-rich cores are the bulk modulus and moduli ratio. Cross-plotting bulk modulus vs. moduli ratio can qualitatively group measured cores and Monte-Carlo simulated realizations into different mineral-rich and saturation states properly. Concerning the factors of boehmite content, porosity, and saturation state, an interpretation template for boehmite-rich coal was proposed and used. As the template interpreted readings close to the measured contents, the built templates can quantitatively interpret boehmite and gallium contents in coal-hosted ores with high precision. In summary, the coal-hosted gallium-rich ores are elastically detectable. Full article
(This article belongs to the Special Issue Critical Metal Minerals in Coal)
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11 pages, 2341 KiB  
Article
In Situ Raman Spectroscopy and DFT Studies of the Phase Transition from Zircon to Reidite at High P–T Conditions
by Yue Gao, Zhi Zheng, Xia Zhao, Yuegao Liu, Jiangzhi Chen, Yan Li, Mengjun Xiong, Xiaotao Zu and Shenghua Mei
Minerals 2022, 12(12), 1618; https://doi.org/10.3390/min12121618 - 15 Dec 2022
Cited by 2 | Viewed by 1323
Abstract
Zircon (ZrSiO4) provides a good pressure-holding environment for ultra-high-pressure metamorphic minerals during crust exhumation due to its high incompressibility and chemical stability. At high pressure, the zircon can transform to reidite. Previous studies show much higher phase-transition pressures at room temperature [...] Read more.
Zircon (ZrSiO4) provides a good pressure-holding environment for ultra-high-pressure metamorphic minerals during crust exhumation due to its high incompressibility and chemical stability. At high pressure, the zircon can transform to reidite. Previous studies show much higher phase-transition pressures at room temperature than those at high temperature (>1000 K) due to kinetic hindrance. To further investigate the kinetics of the zircon–reidite phase transition at relatively low temperatures, the phase boundary at 298–800 K was determined using a diamond anvil cell combined with in situ Raman spectra. The results show that reidite becomes thermodynamically more stable compared with zircon at 8 GPa at room temperature, and the slope of the phase boundary at 298–800 K abruptly differs from that of previous studies at 1100–1900 K. Compared with the equilibrium phase boundary calculated by the density functional theory, it indicates that the kinetic effect of the zircon–reidite phase transition is obvious, and there exists a sufficiently large energy driving force provided by an overpressure to overcome the activation energy barrier below a critical temperature of approximately 880 K. The temperature dependence of overpressure is about 0.023 GPa/K. Full article
(This article belongs to the Special Issue High-Pressure Physical and Chemical Behaviors of Minerals and Rocks)
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2 pages, 187 KiB  
Editorial
Editorial for Special Issue “Valorization of Metallurgical and Mining Residues and Wastes”
by Luis Pérez-Villarejo and George N. Angelopoulos
Minerals 2022, 12(12), 1617; https://doi.org/10.3390/min12121617 - 15 Dec 2022
Viewed by 777
Abstract
This Special Issue has presented the most recent advances in some of the key aspects of mining and metallurgical waste valorization [...] Full article
(This article belongs to the Special Issue Valorization of Metallurgical and Mining Residues and Wastes)
16 pages, 6322 KiB  
Article
Characteristics and Controlling Factors of Natural Fractures in Continental Tight-Oil Shale Reservoir
by Xiaofei Fu, Lei Gong, Xiaocen Su, Bo Liu, Shuai Gao, Jianguo Yang and Xinnan Qin
Minerals 2022, 12(12), 1616; https://doi.org/10.3390/min12121616 - 15 Dec 2022
Cited by 7 | Viewed by 1345
Abstract
Natural fracture growth plays an important role in shale-oil enrichment. Systematically investigating fracture features and their controlling factors in shale-oil reservoirs is essential for accurately predicting fracture distribution. The controlling factors of fracture distribution in the continental shale of the Qingshankou Formation in [...] Read more.
Natural fracture growth plays an important role in shale-oil enrichment. Systematically investigating fracture features and their controlling factors in shale-oil reservoirs is essential for accurately predicting fracture distribution. The controlling factors of fracture distribution in the continental shale of the Qingshankou Formation in the Songliao Basin, China, were systematically analyzed based on the quantitative fracture characterization of outcrops and cores. Strata-confined fractures, throughgoing fractures, bedding-parallel fractures, and stylolites can be observed in the Qingshankou shale reservoir in the study area. Fracture distribution is not only controlled by internal factors, e.g., mineral composition, mechanical stratigraphy, and lithofacies, but also by external factors, e.g., faults and abnormally high pressure readings. Mineral composition is the primary factor governing fracture development, and it not only controls fracture abundance, but it also affects fracture filling and effectiveness. Mechanical stratigraphy determines the spatial morphology and developmental pattern of a fracture. Fractures are well-developed in brittle strata, with fracture spacing being proportional to bed thickness. Lithofacies can determine fracture development by controlling the variation of mineral composition, rock structure, bed thickness, etc. Stress concentration is commonly high at fault tips, intersections, and overlaps, where fracture density is high and has good connectivity. The existence of abnormally high pressure reduces effective stress, promoting shear fracture development. Tensile overpressure fractures can also be generated under small levels of differential stress. Full article
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18 pages, 5147 KiB  
Article
The Origin of Carbonate Components in Carbonate Hosted Pb-Zn Deposit in the Sichuan-Yunnan-Guizhou Pb-Zn Metallogenic Province and Southwest China: Take Lekai Pb-Zn Deposit as an Example
by Zhiwei He, Bo Li, Xinfu Wang, Xianguo Xiao, Xin Wan and Qingxi Wei
Minerals 2022, 12(12), 1615; https://doi.org/10.3390/min12121615 - 15 Dec 2022
Cited by 2 | Viewed by 1506
Abstract
The Lekai lead–zinc (Pb-Zn) deposit is located in the northwest of the Sichuan–Yunnan–Guizhou (SYG) Pb-Zn metallogenic province, southwest China. Even now, the source of the metallogenic fluid of Pb-Zn deposits in the SYG Pb-Zn metallogenic province has not been recognized. Based on traditional [...] Read more.
The Lekai lead–zinc (Pb-Zn) deposit is located in the northwest of the Sichuan–Yunnan–Guizhou (SYG) Pb-Zn metallogenic province, southwest China. Even now, the source of the metallogenic fluid of Pb-Zn deposits in the SYG Pb-Zn metallogenic province has not been recognized. Based on traditional lithography, rare earth elements (REEs), and carbon–oxygen (C–O) isotopes, this work uses the magnesium (Mg) isotopes of hydrothermal carbonate to discuss the fluid source of the Lekai Pb-Zn deposit and discusses the fractionation mechaism of Mg isotopes during Pb-Zn mineralization. The REE distribution patterns of hydrothermal calcite/dolomite are similar to that of Devonian sedimentary carbonate rocks, which are all present steep right-dip type, indicating that sedimentary carbonate rocks may be serve as the main source units of ore-forming fluids. The C–O isotopic results of hydrothermal dolomite/calcite and the δ13CPDB–δ18 OSMOW diagram show that dolomite formation is closely related to the dissolution of marine carbonate rocks, and calcite may be affected to some extent by basement fluid. The Mg isotopic composition of dolomite/calcite ranges from −3.853‰ to −1.358‰, which is obviously lighter than that of chondrites, mantle, or seawater and close to that of sedimentary carbonate rock. It shows that the source of the Mg element in metallogenic fluid of Lekai Pb-Zn deposit may be sedimentary carbonate rock rather than mantle, chondrites, or seawater. In addition, the mineral phase controls the Mg isotope fractionation of dolomite/calcite in the Lekai Pb-Zn deposit. Based on the geological, mineralogical, and hydrothermal calcite/dolomite REE, C–O isotope, and Mg isotope values, this work holds that the mineralization of the Lekai Pb-Zn deposit is mainly caused by basin fluids, influenced by the basement fluids; the participation of basement fluids affects the scale and grade of the deposit. Full article
(This article belongs to the Special Issue Pb-Zn Deposits and Associated Critical Metals)
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15 pages, 2955 KiB  
Article
Archaeometric Classification of Scattered Marble Fragments to Help the Reconstruction of Statues
by Lluís Casas, Roberta Di Febo, Julio César Ruiz, Mauro Brilli, Fabrizio Antonelli and Juan Diego Martín-Martín
Minerals 2022, 12(12), 1614; https://doi.org/10.3390/min12121614 - 15 Dec 2022
Cited by 1 | Viewed by 1670
Abstract
A multi-technique approach combining petrographic, cathodoluminescence, and stable isotope analyses is commonly used in provenance studies of archaeological marbles. In the present paper, this characterization approach transcends provenance, and it is applied to the reconstruction of fragmented sculptures. The potential of this novel [...] Read more.
A multi-technique approach combining petrographic, cathodoluminescence, and stable isotope analyses is commonly used in provenance studies of archaeological marbles. In the present paper, this characterization approach transcends provenance, and it is applied to the reconstruction of fragmented sculptures. The potential of this novel application of archaeometric measurements is illustrated with a case study consisting in 16 scattered marble fragments retrieved from a Roman villa (Els Munts) near Tarraco (presently Northeastern Spain). The samples were grouped taking into account their similarity in quantified parameters such as the cathodoluminescence color clusters and the stable carbon and oxygen isotopic ratios. The results permitted classification of the fragments into three groups corresponding to three different statues depicting Antinous (7 fragments), Minerva goddess (4 fragments), and an undetermined character (3 fragments). Two other fragments could not be ascribed to any particular statue. The archaeometric grouping provides arguments that can be used to confirm or refute archaeological hypotheses of statue reconstructions. Full article
(This article belongs to the Special Issue Colours in Minerals and Rocks, Volume II)
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14 pages, 7673 KiB  
Article
Selective Leaching of Vanadium from Calcification-Roasted Pellets of Vanadium–Titanium–Iron Concentrate by a Cyclic Two-Stage Sulfuric Acid Process
by Zhonghui Peng, Zhixiang Wang, Yang Li, Yongze Zhu and Keqiang Xie
Minerals 2022, 12(12), 1613; https://doi.org/10.3390/min12121613 - 15 Dec 2022
Cited by 1 | Viewed by 1190
Abstract
Here, a process for leaching vanadium from calcified roasting pellets (CPVC) of vanadium–titanium-iron concentrate by a two-stage sulfuric acid cycle was proposed. The first stage of leaching was mainly for the removal of silicon from the pellet and leaching solution. After the second [...] Read more.
Here, a process for leaching vanadium from calcified roasting pellets (CPVC) of vanadium–titanium-iron concentrate by a two-stage sulfuric acid cycle was proposed. The first stage of leaching was mainly for the removal of silicon from the pellet and leaching solution. After the second stage, the total leaching rates of vanadium and iron were 75.52% and 0.71%, respectively. The concentration of vanadium in the leaching solution reached 6.80 g/L, which can subsequently direct a vanadium precipitation process without extraction and enrichment. After the second roasting, the crushing strength of the pellets reached 2250 N, which met the requirement for blast furnace iron making. The Eh-pH diagrams of the V-Fe-H2O system at different temperatures were plotted. Thermodynamically, it was difficult to selectively leach vanadium and iron by changing the conventional acid leaching conditions. In addition, the pellets before and after leaching were analyzed. The grade of iron in the pellets increased slightly after leaching, and the main phases in the pellets remained as Fe2O3 and Fe9TiO15. The S in the sulfuric acid solution entered the leached pellets during the acid leaching reaction and was removed by the second roasting of the leached pellets. Full article
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13 pages, 2620 KiB  
Article
Effect of Water-Air Microemulsion of Flotation Agent Solution on Flotation of Polymetallic Sulfide Ores
by Dulatbek Turysbekov, Nessipbay Tussupbayev, Sabira Narbekova and Zhamikhan Kaldybayeva
Minerals 2022, 12(12), 1612; https://doi.org/10.3390/min12121612 - 14 Dec 2022
Viewed by 1082
Abstract
The enrichment of polymetallic sulfide ore is a complex task. Fine grinding is carried out to reveal useful minerals, resulting in the formation of microparticles. It is difficult to achieve the floatation of microparticles and fine useful minerals are lost with flotation tailings. [...] Read more.
The enrichment of polymetallic sulfide ore is a complex task. Fine grinding is carried out to reveal useful minerals, resulting in the formation of microparticles. It is difficult to achieve the floatation of microparticles and fine useful minerals are lost with flotation tailings. The problem of microparticle flotation can be solved by using air bubbles smaller than 50 µmin for the flotation process. Water-air microemulsion (WAME)of a frothersolution obtained using the generator was used as microbubbles. The effect of WAME on flotation was studied on polymetallic ores and gold-bearing ore from Kazakhstan deposits.The use of WAMEin the processing of polymetallic ore allowed for themaintenance of the quality of rougher concentrates, to increase the copper extraction in Cu-Pb rougherconcentrate by 7.41%, of lead by 5.98% in the copper-lead flotation cycle (Cu-Pb-Zn-Fe ore), copper extraction in Cu-Mo rougherconcentrate by 5.2%, and molybdenum by 4.7% in the copper-molybdenum flotation cycle (Cu-Mo ore). The indicators of flotation gold extraction into the gold-containing concentrate significantly improved in comparison with the basic mode when using the generator in rougher and scavenger flotation cycles: the quality increased by 5.3 g/t, and the extraction increased by 4.27%. Full article
(This article belongs to the Special Issue Advances in Mineral Beneficiation Methods)
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20 pages, 4116 KiB  
Article
Non-Linear Clumped Isotopes from DIC Endmember Mixing and Kinetic Isotope Fractionation in High pH Anthropogenic Tufa
by Chris Holdsworth, John MacDonald and Cedric John
Minerals 2022, 12(12), 1611; https://doi.org/10.3390/min12121611 - 14 Dec 2022
Cited by 3 | Viewed by 1540
Abstract
Clumped isotope values (Δ47) of carbonates forming in high pH conditions do not correspond to mineral precipitation temperatures due to certain effects including kinetic isotope fractionation and dissolved inorganic carbon (DIC) endmember mixing. Field-based archives of these carbonate environments are needed [...] Read more.
Clumped isotope values (Δ47) of carbonates forming in high pH conditions do not correspond to mineral precipitation temperatures due to certain effects including kinetic isotope fractionation and dissolved inorganic carbon (DIC) endmember mixing. Field-based archives of these carbonate environments are needed to evaluate and quantify these effects accurately. In this study, we measure the clumped isotope values of anthropogenic carbonates for the first time. Tufa layers were analyzed from samples precipitating in a high pH (>10) stream that drains a major slag heap in north east England. Δ47 values are 0.044‰–0.183‰ higher than expected equilibrium values. Non-linear distribution of clumped isotope data is diagnostic of DIC endmember mixing, rather than partial equilibration of DIC. Episodic dilution of hydroxide-rich stream waters by equilibrated rainfall surface runoff provides the mechanism by which mixing occurs. Δ47 values are ~0.010‰–0.145‰ higher than linear clumped isotope mixing profiles, suggesting that the majority of Δ47 increase results from a combination of endmember non-linear mixing effects and an atmosphere-hydroxide sourcing of DIC. The diagnostic trends and variation in clumped isotope values present in these results demonstrates the potential of anthropogenic carbonate systems as a useful archive for studying and quantifying kinetic effects in clumped isotopes. Full article
(This article belongs to the Special Issue Geochemistry of Travertines and Calcareous Tufas)
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12 pages, 2199 KiB  
Article
Removal of Pyrrhotite from High-Sulphur Tailings Utilising Non-Oxidative H2SO4 Leaching
by Jarno Mäkinen, Grzegorz Pietek, Ville Miettinen, Mohammad Khoshkhoo, Jan-Eric Sundkvist and Päivi Kinnunen
Minerals 2022, 12(12), 1610; https://doi.org/10.3390/min12121610 - 14 Dec 2022
Viewed by 1476
Abstract
Tailings are a residual material stream produced in the mineral processing of ores. They may contain a major sulphide content that increases the risk of acid rock drainage (ARD) but may also host valuable metals. Tank bioleaching is a technically viable method to [...] Read more.
Tailings are a residual material stream produced in the mineral processing of ores. They may contain a major sulphide content that increases the risk of acid rock drainage (ARD) but may also host valuable metals. Tank bioleaching is a technically viable method to treat sulphide tailings. However, a significant pyrrhotite content may cause increased acid and oxidant consumption and result in longer retention times in a bioleaching process. In this work, non-oxidative H2SO4 leaching of pyrrhotite is studied for high-sulphur tailings, both as a pre-treatment method and to consider the recovery possibilities of Fe and S. Continuous mode validation tests, conducted at 90 °C, pH 1.0 and 106 min retention time, resulted in a complete pyrrhotite dissolution with 427 kg/t acid consumption (as 95% H2SO4). Unwanted dissolution of Ni and Zn was taking place with a leaching yield of 21.5% and 13.5%, respectively, while Co and Cu dissolution was negligible. The continuous mode tests signalled that by shortening the retention time, Ni dissolution could be dramatically decreased. The non-oxidative pyrrhotite leaching produced a H2S-rich gas stream, which could be utilised in later metals’ recovery processes after bioleaching to precipitate (CoNi)S, ZnS and CuS products. The non-oxidative pyrrhotite leaching also produced a FeSO4 solution, with approximately 20 g/L of Fe. Full article
(This article belongs to the Section Mineral Processing and Extractive Metallurgy)
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28 pages, 8838 KiB  
Article
Uranium Mineralization in the MacInnis Lake Area, Nonacho Basin, Northwest Territories: Potential Linkages to Metasomatic Iron Alkali-Calcic Systems
by Kerstin Landry, Erin Adlakha, Andree Roy-Garand, Anna Terekhova, Jacob Hanley, Hendrik Falck and Edith Martel
Minerals 2022, 12(12), 1609; https://doi.org/10.3390/min12121609 - 14 Dec 2022
Viewed by 2090
Abstract
The intracratonic Paleoproterozoic Nonacho Basin, deposited on the western margin of the Rae craton, contains historic polymetallic (i.e., U, Cu, Fe, Pb, Zn, Ag) occurrences spatially associated with its unconformable contact with underlying crystalline basement rocks and regionally occurring faults. This study presents [...] Read more.
The intracratonic Paleoproterozoic Nonacho Basin, deposited on the western margin of the Rae craton, contains historic polymetallic (i.e., U, Cu, Fe, Pb, Zn, Ag) occurrences spatially associated with its unconformable contact with underlying crystalline basement rocks and regionally occurring faults. This study presents the paragenesis, mineral chemistry and geochemistry of uranium mineralized rocks and minerals of the MacInnis Lake sub-basin of the Nonacho Basin, to evaluate the style and relative timing of uranium mineralization. Mineralization is restricted to regionally occurring deformation zones, and post-dates widely spread and pervasive albitization and more local Ba-rich K-feldspar alteration of host rocks. Uranium mineralized rocks show elevated concentration of Cu, Ag and Au relative to variably altered host rocks. Microscopic and compositionally heterogeneous altered uraninite occurs (i) as overgrowths on partially dissolved Cu-sulphides with magnetite in chlorite ± quartz, calcite veins, and (ii) with minor uranophane in hematite-sericite-chlorite ± quartz breccia and stockwork. Both uraninite types are Th poor (<0.09 wt.% ThO2) and variably rich in SO4 (up to 2.26 wt.%), suggesting a low-temperature hydrothermal origin in a relatively oxidized environment. Rare-earth element (+Y) concentrations in type-i uraninite are high, up to 9.5 wt.% Σ(REE+Y)2O3 with CeN/YN values > 1, similar to REE compositions of uraninite in metasomatic iron and alkali-calcic systems (MIAC), including low-temperature hematite-type IOCG-deposits (e.g., Olympic Dam, Gawler Craton, Australia) and albitite-hosted uranium deposits (e.g., Southern Breccia, Great Bear Magmatic Zone, Canada, and Gunnar Deposit, Beaverlodge District, Canada). Both uraninite types are variably rich in Ba (up to 3 wt.% BaO), a geochemical marker for MIAC systems, provided by the dissolution of earlier secondary Ba-rich K-feldspar. Chemical U-Th-Pb dating yields resetting ages of <875 ± 35 Ma for type-ii uraninite-uranophane, younger than strike-slip movement along regional structures of the basin that are spatially associated with the uranium occurrences. We suggest that MacInnis Lake uranium occurrences formed from oxidized hydrothermal fluids along previously altered (albitized, potassically altered) regional-scale faults. Uranium minerals precipitated on earlier Fe-rich sulfides (chalcopyrite, bornite), which acted as a redox trap for mineralization, in low-temperature (~310–330 °C, based on Al-in-chlorite thermometry) breccias and stockwork zones, late in a metasomatic iron and alkali-calcic alteration system. Full article
(This article belongs to the Special Issue Geochemistry, Mineral Chemistry and Geochronology of Uranium Deposits)
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14 pages, 2404 KiB  
Article
Vaterite Synthesized by Waste Liquid of Extracting Chitin from Crab Shells and the Mineral Loading for Doxorubicin Hydrochloride
by Luting Zhang, Peiyuan Sun, Xiaochi An, Xingxing Wang, Siying Li and Bin Lian
Minerals 2022, 12(12), 1608; https://doi.org/10.3390/min12121608 - 14 Dec 2022
Cited by 2 | Viewed by 1380
Abstract
To effectively treat the environmental pollution caused by discarded crab shell, chitin was extracted from discarded crab shells by a combined chemical and biological process. The chitin extraction waste liquid was used to culture bacteria to synthesize biogenic vaterite (BV). The mineral morphology [...] Read more.
To effectively treat the environmental pollution caused by discarded crab shell, chitin was extracted from discarded crab shells by a combined chemical and biological process. The chitin extraction waste liquid was used to culture bacteria to synthesize biogenic vaterite (BV). The mineral morphology and physico-chemical properties of BV were characterized, and the loading characteristics and adsorption mechanism of doxorubicin hydrochloride (DOX) were investigated. The results showed that chitin could be extracted from crab shells using a combination of chemical and biological methods, and the purity of the extracted chitin reached 89.79%; cultivation of Bacillus velezensis using extraction waste liquid can induce the synthesis of stable BV; the maximum drug loading of BV towards DOX was 447.58 mg/g and its adsorption behavior fitted the Freundlich model. The findings provide new information for the processing utilization of waste crab shells and the development of novel drug carriers. Full article
(This article belongs to the Section Biomineralization and Biominerals)
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16 pages, 6221 KiB  
Article
Mud Crab’s Mottled, Deep-Blue Exoskeleton: Surface Morphology and Internal Microstructure
by Tadanobu Inoue, Erina Kitahara, Yuka Hara and Koji Nakazato
Minerals 2022, 12(12), 1607; https://doi.org/10.3390/min12121607 - 14 Dec 2022
Cited by 1 | Viewed by 1360
Abstract
The claws of the mud crab, Scylla serrata, are huge in comparison with its body size. Many bulges ranging from 5 to 23 μm in height and 90 to 146 µm in diameter were observed on the mottled, deep-blue exoskeleton surface of [...] Read more.
The claws of the mud crab, Scylla serrata, are huge in comparison with its body size. Many bulges ranging from 5 to 23 μm in height and 90 to 146 µm in diameter were observed on the mottled, deep-blue exoskeleton surface of the mud crab’s claw. These cuticle bulges were closely related to irregularly present exocuticles on the surface layer of the exoskeleton’s cross section. The bulges exist between the exocuticles, and at the apex of these bulges was a tube that bundled many pore canals that penetrated the exoskeleton. This tube was thick (62–66 µm) near the inner side and narrowed (12–22 µm) toward the outer surface. On the other hand, the exocuticles had a heterogeneous tissue structure in a coarse region extending normally to the surface, with a diameter of 3 to 7 µm, and a dense region between them. Calcium concentrations were high in the dense region, and phosphorus and magnesium concentrations were high in the coarse region. As a result, the mechanical properties (hardness: H and modulus: Er) were distributed inside the exocuticle, and the mapping of H and Er using a nanoindentation test clarified the heterogeneity. Full article
(This article belongs to the Special Issue Feature Papers in Biomineralization and Biominerals)
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