Minerals

13 pages, 3971 KiB

Open AccessArticle

Effect of La Doping and Al Species on Bastnaesite Flotation: A Density Functional Theory Study

by Xiancheng Shao, Guoyuan Wu, Gongliang Jiang, Ye Wang, Shikun Pu, Yaozhong Lan and Dengbang Jiang

Minerals 2023, 13(4), 583; https://doi.org/10.3390/min13040583 - 21 Apr 2023

Cited by 1 | Viewed by 1323

Abstract

The recovery of rare earth elements from ores is crucial because of their applications in modern technology. Bastnaesite (La/Ce(CO₃)F) is typically found in deposits with other gangue minerals but can be purified by flotation. Accordingly, we investigated the interactions of the [...] Read more.

The recovery of rare earth elements from ores is crucial because of their applications in modern technology. Bastnaesite (La/Ce(CO₃)F) is typically found in deposits with other gangue minerals but can be purified by flotation. Accordingly, we investigated the interactions of the collector nonyl hydroxamic acid (NHA) with bastnaesite using density functional theory (DFT) calculations. In addition, we replaced Ce sites on the bastnaesite (100) surface with La and investigated the effect on NHA adsorption. Finally, we examined the effects of co-present aluminum species, which are frequently used inhibitors for associated gangue minerals during bastnaesite flotation, on NHA adsorption and, thus, the flotation efficiency. We found that doping with La increased the strength of adsorption between NHA and the bastnaesite (100) surface. In addition, we found that Al(OH)_3(s) was adsorbed more strongly than NHA. Consequently, when Al(OH)_3(s) is present in the flotation pulp, it is preferentially adsorbed, which reduces the number of sites for NHA adsorption and its flotation efficiency. These findings suggest that La doping can enhance the recovery of bastnaesite and indicate that the presence of Al minerals should be minimized. Full article

(This article belongs to the Special Issue Adsorption of Cations and Anions on Mineral Surfaces)

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15 pages, 7126 KiB

Open AccessArticle

Flocculation Behavior of Ultrafine Silica Particles in Acid Leaching Pulp by Nonionic Polymeric Flocculants

by Bao Guo, Xinlei Zhan, Kaixi Jiang, Hongzhen Xie and Rongdong Deng

Minerals 2023, 13(4), 582; https://doi.org/10.3390/min13040582 - 21 Apr 2023

Cited by 2 | Viewed by 2157

Abstract

Sedimentation of ultrafine silica particles that exist in acid leaching pulp and their separation from Pregnant Leach Solution largely determines the efficiency of a hydrometallurgical process utilizing copper oxide ore. Thickener on a larger scale can allow longer sedimentation, generating low overflow turbidity [...] Read more.

Sedimentation of ultrafine silica particles that exist in acid leaching pulp and their separation from Pregnant Leach Solution largely determines the efficiency of a hydrometallurgical process utilizing copper oxide ore. Thickener on a larger scale can allow longer sedimentation, generating low overflow turbidity but high economic input. In this paper, the flocculation behavior of quartz particles in sulfuric acid solution using nonionic flocculants polyethylene oxide (PEO) and polyacrylamide (PAM), as well as ionic cofactor montmorillonite (MMT) and nonionic cofactor tannic acid (TA), were investigated, with the dynamic size of flocs and counts of fines being monitored using an in situ particle size measurement technique, namely the focused beam reflectance measurement (FBRM), under turbulent conditions. Attention was paid to variables affecting quartz flocculation properties from both physicochemical and hydrodynamic aspects such as shear intensity. The flocculation mechanism was investigated using zeta potential and dynamic light scattering measurements. It was found that the TA promotes the bridging flocculation of PEO-quartz by forming associative complexes with larger clusters in solution, while MMT electrostatically adsorbs on the quartz surface, enhancing its bridging with PAM. Low turbidity benefited from the higher shear resistance of the compact flocs structure provided by PEO/PEO + TA/PAM + MMT. Efficient solid–liquid separation was achieved by using the synergistic flocculation of small molecule cofactors and polymer flocculants. Full article

(This article belongs to the Special Issue Advances on Fine Particles and Bubbles Flotation)

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19 pages, 4639 KiB

Open AccessArticle

Study on Continuously Weakening Mechanism of Heap Leaching Velocity of Weathered Rare Earth Ores with the Increase of Ore Burial Depth

by Defeng Liu, Wenxin Yan, Zhenyue Zhang, Wenda Guo and Ruan Chi

Minerals 2023, 13(4), 581; https://doi.org/10.3390/min13040581 - 21 Apr 2023

Cited by 2 | Viewed by 1603

Abstract

The column leaching experiments, CT, numerical simulation and fractal theory were adopted to study the continuously weakening mechanism of the heap leaching velocity of weathered rare earth ores with the increase of ore burial depth. The variation characteristics of pore structure and the [...] Read more.

The column leaching experiments, CT, numerical simulation and fractal theory were adopted to study the continuously weakening mechanism of the heap leaching velocity of weathered rare earth ores with the increase of ore burial depth. The variation characteristics of pore structure and the seepage law of solution in ore samples at different depths during leaching were explored, respectively. The results showed that the variation of characteristic parameters of the pore structure in the lower ore samples was the main reason for the decrease in the leaching velocity. For the lower ore samples after leaching, the number of pores with a pore volume of less than 0.01 mm³ and a pore radius of less than 0.8 mm increased, while pore connectivity, the fractal dimension of the pore shape, the ratio of pore length to width and pore throat length reduced. The solution paths of the upper and middle ore samples were concentrated while that of the lower samples were few, even interrupted. The pore pressure of the ore samples decreased after leaching, especially that of the lower ore samples. The research results are helpful to enrich the basic theory on the heap leaching of weathered rare earth ores. Full article

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

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21 pages, 8318 KiB

Open AccessArticle

The Carbon and Oxygen Isotope Composition of the Marble Inscriptions of Aléria, Corsica

by Mauro Brilli, Francesca Giustini and Marco Gozzi

Minerals 2023, 13(4), 580; https://doi.org/10.3390/min13040580 - 20 Apr 2023

Cited by 1 | Viewed by 1702

Abstract

Aléria was the main city of the island of Corsica in ancient times. Archaeological excavations in the area where ancient Aléria once stood began between the 1950s and 1960s and brought to light numerous inscriptions mainly carved on slabs of white marble; they [...] Read more.

Aléria was the main city of the island of Corsica in ancient times. Archaeological excavations in the area where ancient Aléria once stood began between the 1950s and 1960s and brought to light numerous inscriptions mainly carved on slabs of white marble; they constitute an important source of knowledge of the city’s institutions, urban topography, society, and economy. The provenance of the marbles, on which the inscriptions were carved, can add important information about the history of the city. A first visual examination of the slabs or slab fragments allows us to state that Carrara is probably the provenance of most of the marbles used. Practical reasons lead us to believe that the provenance of these marbles can be traced back to two main quarry areas: Carrara, or somewhere in Corsica. The determination of the stable isotope composition of these marbles could solve this problem. Carrara marble, in fact, has a narrow range of isotopic variability, with values typical of marine carbonates, that allows for a strong characterization. The petrographic method of investigation was used, as a second step, on a reduced number of marble inscriptions to evaluate the effectiveness of the isotopic characterization of Carrara. The results of the analysis confirmed that most of the gray and white marbles studied have Carrara as their quarrying area; they also revealed that in Corsica the presence of ancient local marble quarries is uncertain, even in Roman times. Full article

(This article belongs to the Special Issue Characterization and Provenance Analysis of Ancient Stone Materials: Insights from Mineralogy, Petrology and Geochemistry)

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14 pages, 6195 KiB

Open AccessArticle

Validation of Bromide Leaching through Response Surface Methodology and Separation of Gold from Waste Printed Circuit Boards

by Mudila Dhanunjaya Rao, Pratima Meshram, Abhilash and Kamalesh K. Singh

Minerals 2023, 13(4), 579; https://doi.org/10.3390/min13040579 - 20 Apr 2023

Cited by 3 | Viewed by 2015

Abstract

The daily consumption of gold is increasing worldwide; however, its availability from conventional ores is reducing. Alternatively, the presence of gold in waste electrical and electronic equipment (WEEE) is nearly 100 times higher than in natural ore. Therefore, the possibility of the recovery [...] Read more.

The daily consumption of gold is increasing worldwide; however, its availability from conventional ores is reducing. Alternatively, the presence of gold in waste electrical and electronic equipment (WEEE) is nearly 100 times higher than in natural ore. Therefore, the possibility of the recovery and separation of gold from waste printed circuit boards of obsolete mobile phones is studied in the present work. Initially, the optimization of parameters for the quantitative gold leaching from metal clads of PCBs with halide salts at acidic conditions is studied through response surface methodology. Three factors (parameters), viz. temperature, time and stirring speed are altered during the experiments based on the central composite design (CCD). Leaching parameters have been optimized with the help of the second-order empirical equations and analysis of variance (ANOVA) for maximum gold dissolution. The selective recovery and separation of gold from leach liquor have been achieved with solvent extraction with an organic amide as extractant followed by cementation with zinc powder. The separated gold powder has also been analyzed with XRD and SEM-EDS to check the purity and homogeneous elemental distribution. The statistical design of experiments and separation processes for the effective recovery of gold corroborates the economic feasibility of the proposed process. Full article

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

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14 pages, 2865 KiB

Open AccessArticle

Estonian Phosphate Rock Dissolution in Hydrochloric Acid: Optimization of Acid Dosage and Concentration

by Kaia Tõnsuaadu, Juha Kallas, Toivo Kallaste, Kristjan Urtson, Marve Einard, Rasmus Martin, Rein Kuusik and Andres Trikkel

Minerals 2023, 13(4), 578; https://doi.org/10.3390/min13040578 - 20 Apr 2023

Cited by 4 | Viewed by 1838

Abstract

The increasing need for phosphorus and rare earth elements (REEs) has initiated the studies of new mineral deposits and new complex processing technologies. Estonian phosphate rock (EPR) resources, which are not in use, are estimated to be more than 3 billion metric tons [...] Read more.

The increasing need for phosphorus and rare earth elements (REEs) has initiated the studies of new mineral deposits and new complex processing technologies. Estonian phosphate rock (EPR) resources, which are not in use, are estimated to be more than 3 billion metric tons or 800 million tons of P₂O₅. The experiments of dissolution of three different EPR samples in hydrochloric acid were carried out with the aim of studying the impact of the chemical and mineralogical composition of EPR on the leaching process. The leaching of P, Ca, Mg, and consumption of H+ ions depend on HCl concentration and dosage. The solubility of fluorine and REEs are also influenced by CaF₂ and REEs-phosphates precipitation. Fe solubility depends on the mineralogical composition of EPR but also on particle size, acid dosage, pH, and phosphorus content in the solution. The dissolution of pyrite is much lower than the solubility of carbonate apatite. Dolomite dissolution depends on the acid dosage and the fractional composition of EPR. Dolomite dissolution also rests lower than that of apatite. For all the samples studied, the best regression models that describe P, Mg, and Ca solubility and the optimum concentration of HCl for phosphorus dissolution were found using mathematical modeling. Full article

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

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14 pages, 3545 KiB

Open AccessArticle

The Mechanism Driving Magnetic Enhancement in the Sediments of Core PT2 from Southwestern China

by Ziyi Yang, Xinwen Xu, Fangshe Yang, Qiongqiong Wang and Xiaoke Qiang

Minerals 2023, 13(4), 577; https://doi.org/10.3390/min13040577 - 20 Apr 2023

Viewed by 1411

Abstract

Lacustrine sediments are good recorders of palaeoenvironment changes and have been widely studied in recent years. The study of lacustrine sediments in Southwest China will improve our understanding of the complex environmental evolution history of Southwest China. Therefore, this paper presents a high-resolution [...] Read more.

Lacustrine sediments are good recorders of palaeoenvironment changes and have been widely studied in recent years. The study of lacustrine sediments in Southwest China will improve our understanding of the complex environmental evolution history of Southwest China. Therefore, this paper presents a high-resolution rock magnetism study from the Pengtun drilling hole (PT2) in the Heqing Basin, Southwest China. The results show that the dominant magnetic minerals in the PT2 drill core are magnetite, maghemite and haematite. The magnetic susceptibility (χ) of the upper part of the core (0–13.5 m) is lower than that of the lower part (13.5–33.5 m). There is no maghemite in the upper sections. The minerals with high χ values have the characteristics of pseudosingle-domain (PSD), single-domain (SD), superparamagnetic (SP) and multidomain (MD) grains. The magnetic domains are widely distributed, and the particles are coarser. When χ is low, the magnetic domains of the different samples vary greatly, and the particles are finer. Combined with the magnetic and nonmagnetic characteristics of the sediment, we infer that the change in χ in the PT2 drill core is related to clastic input, water erosion, and reductive dissolution. Full article

(This article belongs to the Special Issue Mineralogical and Magnetostratigraphic Study of Sediments: Implications for Tectonic History of The Tibetan Plateau)

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17 pages, 5311 KiB

Open AccessArticle

Palaeoweathering Conditions, Provenance, and Tectonic Setting of the Early Silurian Longmaxi Formation in the Upper Yangtze Region (Southern China): Evidence from Geochemistry

by Liang Zhao, Yong Li, Chengjie Zou, Shaoze Zhao and Chaorong Wu

Minerals 2023, 13(4), 576; https://doi.org/10.3390/min13040576 - 20 Apr 2023

Cited by 4 | Viewed by 1681

Abstract

The Longmaxi-1 black shales in the Upper Yangtze region are a vital source rocks in southern China. This study investigates the palaeoweathering conditions, provenance, and tectonic setting of the Longmaxi-1 black shale from an elemental geochemical perspective, ultimately revealing its tectonic setting. The [...] Read more.

The Longmaxi-1 black shales in the Upper Yangtze region are a vital source rocks in southern China. This study investigates the palaeoweathering conditions, provenance, and tectonic setting of the Longmaxi-1 black shale from an elemental geochemical perspective, ultimately revealing its tectonic setting. The results showed that the Longmaxi-1 black shales in the sedimentary period have the characteristics of primary deposition. The Longmaxi-1 black shales were deposited as a primary deposition under a mainly humid climate. However, fluctuations in climatic conditions were recorded from the bottom to the upper part of the formation. The parent rock of the Longmaxi-1 black shales in the Upper Yangtze region is a mixture provenance, mainly composed of intermediate-acid volcanic lithologies (granite and granodiorite), followed by mature quartzite and basalt. Black shale deposition is related to the tectonic setting of active continental margin and island arc-continent collision. The Cathayian orogenic belts and the North Qiangling orogenic belt may have played a role in the genesis of the Longmaxi-1 black shales within the Upper Yangtze region. This study provides significant clues regarding the reconstruction of the palaeoclimatic and palaeogeographical conditions of the Upper Yangtze region during the Early Silurian period. Full article

(This article belongs to the Special Issue The Relationship between Metal Deposits and Hydrocarbon Accumulation)

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17 pages, 5949 KiB

Open AccessArticle

The Depositional Environment of the Lacustrine Source Rocks in the Eocene Middle Number of the Liushagang Formation of the Weixinan Sag, Beibuwan Basin, China: Implications from Organic Geochemical Analyses

by Xiaoyong Yang, Xiaoxia Lv, Yahao Huang, Yunlong He, Rui Yang, Ruyue Wang and Peng Peng

Minerals 2023, 13(4), 575; https://doi.org/10.3390/min13040575 - 20 Apr 2023

Viewed by 1694

Abstract

The Eocene middle number of the Liushagang Formation (LS2) of the Weixinan Sag, Beibuwan Basin, characterized by a thick succession of excellent quality source rocks, is composed of lacustrine organic-rich shales, mudstones, and shales (mudstones/shales). However, the complex and specific depositional environment in [...] Read more.

The Eocene middle number of the Liushagang Formation (LS2) of the Weixinan Sag, Beibuwan Basin, characterized by a thick succession of excellent quality source rocks, is composed of lacustrine organic-rich shales, mudstones, and shales (mudstones/shales). However, the complex and specific depositional environment in the source rocks of LS2 raise questions about the mainly controlling factors of lacustrine organic matter (OM) accumulation. In this study, total organic carbon (TOC) contents, Rock-Eval pyrolysis, as well as biomarker data are used to investigate the nature of the depositional environment and the enrichment mechanism of OM in the source rocks of LS2. The values of T_max, CPI, C₂₉ steranes αββ/(ααα+αββ), and the 22S/(22S+22R) ratios of the 17α, 21β(H)-C₃₁ hopane together confirm that the OM in the source rocks of LS2 is immature to of low maturity, which suggests that the nature of biomarkers may not be affected by thermal maturity. The hydrocarbon potential was higher in the organic-rich shales (with a mean of 20.99 mg/g) than in the mudstones/shales (with a mean of 7.10 mg/g). The OM in organic-rich shales is type I and II kerogen and that in mudstones/shales is type II kerogen. The C₂₇/C₂₉ regular steranes ratios and 4-methylsterane indices (4MSI) further confirmed the difference in the source of OM between organic-rich shales and mudstones/shales; that is, that the OM of organic-rich shales is mainly derived from the lake algae and aquatic macrophytes and the OM of mudstones/shales is mainly from the higher plants. The values of the gammacerane index and ratios of C₂₁/C₂₃ TT and C₂₄ Tet/C₂₆ TT all indicate that the source rocks from LS2 are deposited in freshwater to a low salinity water column. Moreover, a cross-plot of C_21–22/C_27–29 sterane versus dia/reg C₂₇ sterane ratios and Pr/Ph ratios suggests that the source rocks from LS2 are recorded to have sub-oxic to oxic conditions. Based on those analyses, two dynamical formation models were proposed: a high-productivity and oxic-suboxic dynamical formation model (Model A) and a low-productivity and oxic-suboxic dynamical formation model (Model B). Full article

(This article belongs to the Topic Hydrocarbon Generation and Accumulation in Unconventional Shale Reservoir: Up-to-Date Advances in Theory, Experiment, Method and Application, Volume II)
(This article belongs to the Section Mineral Exploration Methods and Applications)

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15 pages, 3982 KiB

Open AccessArticle

Reconstructing the Tectonic History of the Arabian–Nubian Shield in Sinai: Low-Temperature Thermochronology Implications on Wadi Agar Area

by Sherif Mansour, Noriko Hasebe, Kamal Abdelrahman, Mohammed S. Fnais and Akihiro Tamura

Minerals 2023, 13(4), 574; https://doi.org/10.3390/min13040574 - 20 Apr 2023

Cited by 6 | Viewed by 2063

Abstract

The Arabian–Nubian Shield envelops the entire regional tectonic history from its formation during the Ediacaran to the Red Sea/Gulf of Suez rifting in the Oligocene–Miocene. The occurrence and extent of the expected successive tectonic events on Sinai basement rocks remain uncertain. Integration of [...] Read more.

The Arabian–Nubian Shield envelops the entire regional tectonic history from its formation during the Ediacaran to the Red Sea/Gulf of Suez rifting in the Oligocene–Miocene. The occurrence and extent of the expected successive tectonic events on Sinai basement rocks remain uncertain. Integration of thermochronological techniques with time–temperature modelling has proven to be a powerful tool for thermal-tectonic history reconstruction. Therefore, we collected representative samples from the Arabian–Nubian Shield basement rocks of the Wadi Agar area at the eastern flank of the Suez rift. Zircon fission-track data show two cooling age possibilities of Ediacaran and Devonian ages. Meanwhile, apatite fission-track data represent three cooling age spans of Carboniferous, Triassic, and Cretaceous. The integration of these data with the modelled time–temperature histories reveals four different cooling events synchronous with the regional events; (1) the Neoproterozoic post-accretion erosional event that causes near-surface rock uplift, (2) the Devonian–Carboniferous Hercynian tectonic event which affected the region with rocks exhumation of ca. 4.2 ± 1.4 km, (3) the Triassic Gondwana breakup initiation, and (4) the Oligocene–Miocene Gulf of Suez rifting which caused flanks uplift in the studied region of ca. 1.2 ± 0.4 km. The Gulf of Suez is a passive rift with a dominant mechanical component that is divided into two differently exhumed northern and southern segments, where an additional far-field thermal overprint was restricted to the southern segment. Full article

(This article belongs to the Special Issue Mineralogy and Geochemistry of Mafic-Ultramafic Assemblages and Associated Ore Deposits)

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17 pages, 3085 KiB

Open AccessArticle

Brine–Melts and Fluids of the Fe-F-P-(Ba)-(Sr)-REE Central Asian Carbonatite Province (Southern Siberia and Mongolia): The Petrogenetic Aspects

by Ilya Prokopyev, Anna Doroshkevich and Anna Redina

Minerals 2023, 13(4), 573; https://doi.org/10.3390/min13040573 - 19 Apr 2023

Cited by 4 | Viewed by 1644

Abstract

The carbonatite complexes of the Central Asian carbonatite province comprise the Siberian carbonatites of the Western Transbaikalia and the Central Tuva regions, as well as those from the Mushugai-Khudag complex in Southern Mongolia. They are confined to Late Mesozoic rift structures and have [...] Read more.

The carbonatite complexes of the Central Asian carbonatite province comprise the Siberian carbonatites of the Western Transbaikalia and the Central Tuva regions, as well as those from the Mushugai-Khudag complex in Southern Mongolia. They are confined to Late Mesozoic rift structures and have endured considerable tectono-magmatic processes caused by intense plume activity, which also accompanied their formation. A systematic study of melt and fluid inclusions revealed that these carbonatites formed as a result of immiscibility processes in silicate–carbonate (salt) melts, as well as fractional crystallization. Alkaline–carbonatite rocks crystallized in the presence of brine–melts with different compositions, i.e., alkaline–fluorine, carbonate, sulfate, phosphate, and chloride. These melts are responsible for mineralization during the orthomagmatic stage and the primary phase of Fe-F-P-(Ba)-(Sr)-REE ore formation at temperature ranges of 850–830 °C, 650–610 °C, and 560–440 °C and pressures between 290 and 350 MPa. At a later stage, the brine–melts evolved into saline hydrothermal fluids, which are considered to be the source of the second stage of F-(Ba)-(Sr)-REE ore mineralization. The saline crystal–fluid inclusions consist mainly of fluorine–sulfate–carbonate–chloride and bicarbonate–chloride compositions, with temperatures of approximately 480–250 °C and pressures below 250 MPa. The shift from melt to fluid in carbonatite complexes could occur more frequently in nature than previously believed and could also apply to other F-REE carbonatite complexes that are linked to rifting and plume activity in mountain-building zones. Full article

(This article belongs to the Special Issue Petrology and Ores of Igneous Alkaline Rocks and Carbonatites, Volume II)

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24 pages, 10362 KiB

Open AccessArticle

Silver(I) Recovery by Ion Flotation Process from Aqueous Solutions in Cells with Spargers

by Laura P. Ángeles Palazuelos, Mizraim U. Flores Guerrero, Miguel Pérez Labra, Iván A. Reyes Domínguez, Ramiro Escudero García, Francisco Patiño Cardona, Francisco R. Barrientos Hernández, Julio C. Juárez Tapia and Martín Reyes Pérez

Minerals 2023, 13(4), 572; https://doi.org/10.3390/min13040572 - 19 Apr 2023

Cited by 3 | Viewed by 1637

Abstract

Extractive metallurgy has recently turned its attention to waste treatment for the recovery of precious metals through innovative metallurgical processes, such as ion flotation. This work studied the influence of several chemical and physical factors, such as the concentration of xanthate [x], frother [...] Read more.

Extractive metallurgy has recently turned its attention to waste treatment for the recovery of precious metals through innovative metallurgical processes, such as ion flotation. This work studied the influence of several chemical and physical factors, such as the concentration of xanthate [x], frother agent [e], dithiophosphate [xl], pH, superficial gas velocity Jg, percentage of gas holdup Eg, bubble diameter (Db) calculated with the drift flux model, and the type of sparger, in the efficiency of silver(I) recovery by the ion flotation technique in sub-aerated cells. The results obtained indicate a 90.7% v/v recovery of silver(I) under conditions of 3.77 × 10⁻⁴ M [x], 1.25 × 10⁻⁴ M [e], Jg 0.5 cm/s, Jl 0.19 cm/s, Eg of 4.1% v/v, and Optimal Db of 0.11 cm, with a rigid bubble generator, achieving an apparent flotation kinetics of 4.16 1/min. The use of combinations [x]–[xl] achieve a silver(I) recovery of 86.9% with a Jg of 1.0 cm/s. The best recovery efficiencies achieved 93% w/w silver(I) are with pH 8.0, [e] of 1.25 × 10⁻⁴, Jl of 0.19 (cm/s) and a rigid sparger compared to a flexible one. Full article

(This article belongs to the Special Issue Recent Advances in Extractive Metallurgy)

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37 pages, 15726 KiB

Open AccessReview

Evolution, Magmatic Source and Metallogenesis of A-Type Granites in the Fanchang Volcanic Basin, Middle and Lower Yangtze Metallogenic Belt: A Review

by Songsong Zhang, Xiaoyong Yang and Lei Liu

Minerals 2023, 13(4), 571; https://doi.org/10.3390/min13040571 - 18 Apr 2023

Cited by 1 | Viewed by 1706

Abstract

The Fanchang volcanic basin (FVB) is located in the Middle and Lower Yangtze Metallogenic Belt (MLYMB) between the ore districts of Ningwu and Tongling. The existing ore deposits in the FVB are relatively small in scale and related to late Mesozoic A-type granites. [...] Read more.

The Fanchang volcanic basin (FVB) is located in the Middle and Lower Yangtze Metallogenic Belt (MLYMB) between the ore districts of Ningwu and Tongling. The existing ore deposits in the FVB are relatively small in scale and related to late Mesozoic A-type granites. In this paper, the crystallization age, major and trace element composition, and Sr-Nd and Hf isotope compositions of the A-type granites are summarized from the literature; in addition, the magnetite composition, H and O isotopes of fluid inclusions, and sulfur isotope composition of metal sulfides in some typical ore deposits in the FVB are also summarized to give insights into the petrogenesis and mineralization of the A-type granites intruding into the FVB. The results show that: (1) Orthopyroxene, plagioclase, K-feldspar, and biotite are the main fractionating minerals controlling the evolution of the magmas of A-type granites in the FVB and other areas in the MLYMB. (2) The whole-rock Sr-Nd and zircon Hf isotopic characteristics show that the source of A-type granite magma is complex and includes the enriched mantle, lower crust, and upper crust, probably with stronger participation of Archaean–Paleoproterozoic crustal materials in the FVB granites than in other regions of the MLYMB. (3) The ores in the FVB are dominated by skarn and hydrothermal deposits. H and O isotopes of fluid inclusions indicate that ore-forming fluids have been derived from mixtures of magmatic hydrothermal fluid, meteoric waters, and deep brine related to gypsum layers. S isotopes of metal sulfides indicate that the sulfur may be a mixture of magmatically derived sulfur and sulfur originating from the Triassic gypsum-bearing layers. The deposit and ore characteristics of the main deposits in the FVB are also illustrated, and the evaluation of metal resources indicates that the skarn and hydrothermal iron–zinc ores in the FVB also have potential as sources of Cd, Ga, and Se. In addition, in terms of the oxygen fugacity, rock type, and geochemical characteristics of magmatic rocks, the metallogenic characteristics and potential of the A-type granites in the FVB are evaluated. It is considered that in addition to the dominant constituents of iron and zinc and the minor constituents listed above, the FVB could have the potential for providing copper, gold, molybdenum, uranium, and other metals as well. Full article

(This article belongs to the Special Issue Granitic Intrusion and Related Mineralization in Asia)

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20 pages, 10163 KiB

Open AccessArticle

Research on Engineering Practice and Effect Evaluation Method of Pressure Relief in Deep Rock Burst Danger Area of Coal Mine

by Jiazhuo Li, Shun Liu, Wentao Ren, Hui Liu, Songyue Li and Kangxing Yan

Minerals 2023, 13(4), 570; https://doi.org/10.3390/min13040570 - 18 Apr 2023

Cited by 4 | Viewed by 1652

Abstract

With a gradual increase in coal mining depth, the underground geological situation is more complex and the threat of rock bursts is more prominent due to the cross influence of multiple factors, such as faults, thick hard roofs, coal pillars, and high in [...] Read more.

With a gradual increase in coal mining depth, the underground geological situation is more complex and the threat of rock bursts is more prominent due to the cross influence of multiple factors, such as faults, thick hard roofs, coal pillars, and high in situ stress areas. Additionally, it is difficult to test the effectiveness of multiple pressure relief measures after implementation in mining areas with rock burst dangers. By evaluating the geology and mining conditions of panel 5308 of the Tangkou coal mine, pressure relief prevention and control technology, combining pre-pressure relief and a danger relief measure, was proposed. An evaluation method for pressure relief implementation in deep mine rock burst danger areas was proposed, with changing rates of event frequency in microseismic high-energy intervals, changing rates of the mean values of hydraulic-powered support stress, and changing rates of bursting strain energy as evaluation indicators. The weight of each indicator was determined based on an analytic hierarchy process. The degree of pressure relief was measured by the pressure relief interval index. The comprehensive pressure relief effect index was calculated by an interval index and by a weight vector. Additionally, the classification standard of the pressure relief effect was proposed. The results show that the frequency of microseismic high-energy interval events decreased by 34.9%, the mean value of hydraulic-powered support stress decreased by 12.7%, and the bursting strain energy decreased by 14.7% after pressure relief was applied at panel 5308. Additionally, the interval indexes corresponding to each indicator were 3, 2, and 2 and the pressure relief effect index was 2.55, so the destress effect was good. The drilling method monitoring data show that the average value of the drilling powder decreased by 18% after pressure relief compared with before and the overall effect was good, which is consistent with the evaluation results of the multi-dimensional pressure relief implementation effect evaluation system, indicating that the evaluation system can accurately test the effectiveness of the multi-dimensional pressure relief implementation effect in deep mine rock burst danger areas. The results of the study provide methodological support and reference for the monitoring and prevention of rock bursts in mines with similar geological conditions. Full article

(This article belongs to the Topic Dynamic Disaster Control, Mine Multi-Source Disaster Monitoring and Intelligent Analysis)

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12 pages, 3000 KiB

Open AccessArticle

Provenance Analysis of the Ojén Nappe and Its Implication for the Geodynamic History (Alpujárride Complex, Betic Cordilleras, Spain)

by José Julián Esteban, Julia Cuevas and José María Tubía

Minerals 2023, 13(4), 569; https://doi.org/10.3390/min13040569 - 18 Apr 2023

Cited by 1 | Viewed by 1165

Abstract

The Ojén nappe, an allochthonous unit that underlies the Ronda peridotites (Betic Cordilleras), is composed of Triassic marbles overlying a metapelitic sequence. In order to carry out an LA-ICP-MS U-Pb age determination and provenance analysis, detrital zircon grains from two quartzites interlayered within [...] Read more.

The Ojén nappe, an allochthonous unit that underlies the Ronda peridotites (Betic Cordilleras), is composed of Triassic marbles overlying a metapelitic sequence. In order to carry out an LA-ICP-MS U-Pb age determination and provenance analysis, detrital zircon grains from two quartzites interlayered within marbles and metapelites were extracted. The obtained results yield the youngest zircon population of 254 ± 3 Ma (Late Permian) with a mean Th/U ratio of 0.34 that supports both the Permian–Triassic age of the marble member and the felsic magma nature for zircon-bearing protoliths. The Permian zircons exhibit tight age peaks in three main populations of 292 ± 2 Ma, 278 ± 3 Ma, and 254 ± 3 Ma, in agreement with the main age populations reported from rhyolites and shallow crustal basaltic–andesite subalkaline rocks emplaced in transtensional Permian basins of the Variscan Orogen during the break-up of Pangea. Moreover, the analyzed detrital zircon grains yield age distributions with clear Tonian–Stenian (ca. 950–975 Ma), Ediacaran–Cryogenian (ca. 560–615 Ma), Ordovician (ca. 460–465 Ma), and Cisuralian peaks (ca. 280–290 Ma) and smoothed Mesoproterozoic peaks that point to a weak and residual Cadomian peri-Gondwanan terrane inheritance. The identified Middle Ordovician detrital zircon populations (460–465 Ma) strengthen the hypothesis that the Alborán domain would be located along the southern passive margin of the European Hunic superterrane. Full article

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

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16 pages, 7299 KiB

Open AccessArticle

Mineralogy and Mineral Chemistry of the Au-Ag-Te-(Bi-Se) San Luis Alta Deposit, Mid-South Peru

by Pura Alfonso, Elsa Ccolqque, Maite Garcia-Valles, Arnau Martínez, Maria Teresa Yubero, Hernan Anticoi and Nor Sidki-Rius

Minerals 2023, 13(4), 568; https://doi.org/10.3390/min13040568 - 18 Apr 2023

Cited by 1 | Viewed by 2073

Abstract

A mineralogical and mineral chemistry study was carried out in the San Luis Alta telluride-rich gold deposit, mid-south Peru, to contribute towards determining its formation and improving the ore processing. The San Luis mineralization is considered an intrusion-related gold deposit located in the [...] Read more.

A mineralogical and mineral chemistry study was carried out in the San Luis Alta telluride-rich gold deposit, mid-south Peru, to contribute towards determining its formation and improving the ore processing. The San Luis mineralization is considered an intrusion-related gold deposit located in the Arequipa segment of the Coastal Batholith. The mineralization occurs in quartz veins hosted in diorites and granodiorites from the Tiabaya Super-Unit. These veins are sulfide-rich in the deep areas and contain abundant iron oxides. Sulfides are mainly pyrite with minor chalcopyrite and galena. Native gold and telluride minerals are abundant. Mineral chemistry was determined using an electron microprobe. The mineralogy of veins was classified into four stages. Gold occurs in the three last stages either in large grains, visible to the naked eye, or, more frequently, in grains of less than 10 µm. Gold appears as grains encapsulated in pyrite, Fe oxides, quartz and filling fractures. The first stage is characterized by the deposition of quartz and massive pyrite, which does not contain gold. During the second stage, hessite, calaverite, petzite and altaite are formed. Additionally, Bi-tellurides, mainly volynskite, rucklidgeite, kochkarite and tellurobusmuthine, are formed. Some of these minerals occur as blebs encapsulated in pyrite, suggesting that a Bi-Te-rich melt was formed from the ore-forming hydrothermal fluid and transported the Au and Ag elements. This stage was followed by a fracturing event and tellurobismuthite, tetradymite and montbrayite precipitated. In the last stage, a supergene replacement formed covellite, bornite and goethite. Te-Bi minerals do not appear in this stage, but selenium minerals occur in minor amounts. Chlorargyrite and iodargyrite occur and are associated with gold. Full article

(This article belongs to the Special Issue Recent Contributions of Female Scientists to the Advancement of Mineral Science)

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19 pages, 6553 KiB

Open AccessFeature PaperArticle

Insight into the Potential Antioxidant and Antidiabetic Activities of Scrolled Kaolinite Single Sheet (KNs) and Its Composite with ZnO Nanoparticles: Synergetic Studies

by Hassan Ahmed Rudayni, Malak Aladwani, Lina M. Alneghery, Ahmed A. Allam, Mostafa R. Abukhadra and Stefano Bellucci

Minerals 2023, 13(4), 567; https://doi.org/10.3390/min13040567 - 18 Apr 2023

Cited by 3 | Viewed by 1919

Abstract

The kaolinite sheets were scrolled by sonication-induced chemical delamination processes into well-developed nanotubes (KNs) which were used as substrates for microwave-based ZnO nanoparticles (ZnO/KNs). The biological activities of synthetic ZnO/KNs structures, in terms of the antioxidant and antidiabetic properties, were assessed in comparative [...] Read more.

The kaolinite sheets were scrolled by sonication-induced chemical delamination processes into well-developed nanotubes (KNs) which were used as substrates for microwave-based ZnO nanoparticles (ZnO/KNs). The biological activities of synthetic ZnO/KNs structures, in terms of the antioxidant and antidiabetic properties, were assessed in comparative studies with the separated phases of the synthetic ZnO and KNs as well as the commercially used ZnO. The KNs substrate resulted in a notable enhancement in the antioxidant and antidiabetic properties of ZnO, which was assigned positive influence on the surface area, interactive interfaces, charge separation, and agglomeration properties of ZnO in addition to the detectable bioactive properties of the KNs structure. The ZnO/KNs structure achieved remarkable scavenging efficiencies for 1, 1-diphenyl-2-picrylhydrazil (DPPH) (89.8 ± 1.57%), nitric oxide (90.6 ± 1.63%), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) (86.8 ± 1.28%), and superoxide (43.9 ± 1.72%) radicals. Additionally, it shows high inhibition effects on porcine α-amylase (84.3 ± 1.92%), crude α-amylase (70.6 ± 1.37%), pancreatic α-Glucosidase (94.7 ± 1.54%), crude α-Glucosidase (95.4 ± 1.64%), and amyloglucosidase (95.3 ± 1.32%) enzymes. This antidiabetic activity is significantly higher than the activity of miglitol and close to or slightly higher than acarbose, which leads us to recommend the use of ZnO/KNs when considering the cost and side effects of the commercially used drugs. Full article

(This article belongs to the Special Issue Biology Meets Mineralogy: Investigations into Biomolecule Interactions with Aluminosilicate Clay Minerals and Layered Double Hydroxides)

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15 pages, 7621 KiB

Open AccessFeature PaperArticle

Comparison of Quantitative X-ray Diffraction Mineral Analysis Methods

by Jingyun Xiao, Yougui Song and Yue Li

Minerals 2023, 13(4), 566; https://doi.org/10.3390/min13040566 - 18 Apr 2023

Cited by 12 | Viewed by 7802

Abstract

X-ray diffraction (XRD) analysis, as one of the most powerful methods, has been widely used to identify and quantify minerals in earth science. How to improve the precision of mineral quantitative analysis is still a hot topic. To date, several quantitative methods have [...] Read more.

X-ray diffraction (XRD) analysis, as one of the most powerful methods, has been widely used to identify and quantify minerals in earth science. How to improve the precision of mineral quantitative analysis is still a hot topic. To date, several quantitative methods have been proposed for different purposes and accompanied by diverse software. In this study, three quantitative mineral analysis methods, including the reference intensity ratio (RIR), Rietveld, and full pattern summation (FPS) methods, are compared and evaluated to systematically investigate their accuracy and applicability. The results show that the analytical accuracy of these methods is basically consistent for mixtures free from clay minerals. However, there are significant differences in accuracy for clay-mineral-containing samples. In comparison, it seems that the FPS method has wide applicability, which is more appropriate for sediments. The Rietveld method has been shown to be capable of quantifying complicated non-clay samples with a high analytical accuracy; nevertheless, most conventional Rietveld software fails to accurately quantify phases with a disordered or unknown structure. The RIR method represents a handy approach but with lower analytical accuracy. Overall, the present results are expected to provide a potentially important reference for the quantitative analysis of minerals in sediments. Full article

(This article belongs to the Special Issue Geochemistry and Mineralogy of Clays and Their Application to Paleoclimatic and Paleoenvironmental Reconstruction)

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17 pages, 6814 KiB

Open AccessArticle

Late Devonian A-Type Granites from the Beishan, Southern Central Asia Orogenic Belt: Implications for Closure of the Paleo-Asia Ocean

by Erteng Wang, Xinwei Zhai, Wanfeng Chen, Lei Wu, Gaorui Song, Yun Wang, Zhiang Guo, Jiaolong Zhao and Jinrong Wang

Minerals 2023, 13(4), 565; https://doi.org/10.3390/min13040565 - 18 Apr 2023

Cited by 3 | Viewed by 1698

Abstract

The closing time of the Paleo-Asian Ocean (PAO) has long been in the focus of research as well as of controversial debates. The Paleozoic A-type granites distributed in the Beishan Orogenic Belt (BOB) at the southern margin of the Central Asian Orogenic Belt [...] Read more.

The closing time of the Paleo-Asian Ocean (PAO) has long been in the focus of research as well as of controversial debates. The Paleozoic A-type granites distributed in the Beishan Orogenic Belt (BOB) at the southern margin of the Central Asian Orogenic Belt (CAOB) provide pivotal clues to constrain the closure of the PAO. In this paper, the newly recognized Duhongshan A-type granites from the middle Huaniushan arc in the BOB (zircon LA-ICP-MS U-Pb ages of ca. 376–374 Ma) are thoroughly studied. The rocks have high SiO₂, K₂O contents with peralkaline character, and display high Zr + Nb + Ce + Y contents (354–543 ppm), 10,000 × Ga/Al (4.1–4.9), Y/Nb (3.2–5.3), Rb/Nb ratios (8.5–14.1), and a zircon saturation temperature in the range of 877–950 °C, indicative of A2-type granites affinities. The Duhongshan granites display enriched in Th and U; depleted in Ba, Sr, and Ti; with slightly positive whole-rock ε_Nd(t) values (+1.86 to +2.21), indicating an origin related to partial melting of lower crustal material in post-collision extension settings. Combined with previous reported results, we conclude that the granitoids in the middle Huaniushan arc were mostly formed around 424–367 Ma and can be divided into two types based on petrochemistry: (a) A-type granites, which generally have high SiO₂ and K₂O, derived from the relatively shallow crustal source in post-collision tectonic settings; and (b) adakite and I-type granites, which display high Sr/Y ratios as well as Nb, Ta, and Ti depletion, likely generated from the melting of juvenile crust in active continental margin arcs. Integrating the previous regional investigations, we propose that the Hongliuhe–Niujuanzi–Xichangjing Ocean (HNXO) of the PAO was closed and transformed in the post-collision extensional tectonic stage during the Late Devonian and formed as post-collision magmatism, while the arc magmatism may be related to the subduction of the Liuyuan Ocean, which is located in the Southern HNXO. Full article

(This article belongs to the Special Issue Petrogenesis, Geochronology, Mineralization and Geochemistry of Granite Rocks)

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18 pages, 10029 KiB

Open AccessEditor’s ChoiceArticle

Preparation and Properties of Phosphoric Acid-Based Porous Geopolymer with High Magnesium Nickel Slag and Fly Ash

by Xingchun Yang, Yuan Wu, Zhigao Sun, Yufeng Li, Dongsheng Jia, Dongliang Zhang, Dehua Xiong and Mitang Wang

Minerals 2023, 13(4), 564; https://doi.org/10.3390/min13040564 - 17 Apr 2023

Cited by 6 | Viewed by 2731

Abstract

Phosphoric acid-based porous geopolymers were prepared by two different foaming agents (H₂O₂ and Al powder) with phosphoric acid as the activator. High-magnesium nickel slag (HMNS) and fly ash (FA) were the precursor combination. The effects of foaming agent types and [...] Read more.

Phosphoric acid-based porous geopolymers were prepared by two different foaming agents (H₂O₂ and Al powder) with phosphoric acid as the activator. High-magnesium nickel slag (HMNS) and fly ash (FA) were the precursor combination. The effects of foaming agent types and contents on the properties of HMNS-FA-phosphate-based porous geopolymers were investigated in terms of dry density, pore structure, compressive strength, thermal conductivity, and water absorption. The phase was analyzed by x-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). It was found that both foaming agents could successfully prepare porous geopolymers, and the compressive strength and dry density of porous geopolymers gradually decreased and the low-thermal conductivity and water absorption gradually increased with the increase in foaming agent content. The foaming agents formed porous structures inside porous geopolymers but did not affect the phases of geopolymerization reactions. This study demonstrates that both foaming agents can be used to prepare HMNS-FA-phosphate-based porous geopolymers for the application of phosphate-activated geopolymers in the direction of refractory materials. Full article

(This article belongs to the Special Issue Metallurgical Solid Waste: Mineralogy, Chemistry and Application/Treatment)

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16 pages, 5703 KiB

Open AccessArticle

Deformation Mechanisms of Magnesium Silicate Hydrate Cement with a Shrinkage-Reducing Admixture under Different Curing Conditions

by Tingting Zhang, Hao Fu and Junnan Han

Minerals 2023, 13(4), 563; https://doi.org/10.3390/min13040563 - 17 Apr 2023

Cited by 4 | Viewed by 1499

Abstract

Magnesium silicate hydrate (M-S-H) cement, a type of green building material, has poor volume stability (i.e., large shrinkage deformation), which limits its application. As a new type of admixture, the behavior of a shrinkage-reducing admixture (SRA) in M-S-H cement has not been studied. [...] Read more.

Magnesium silicate hydrate (M-S-H) cement, a type of green building material, has poor volume stability (i.e., large shrinkage deformation), which limits its application. As a new type of admixture, the behavior of a shrinkage-reducing admixture (SRA) in M-S-H cement has not been studied. Therefore, in this research, the effect of SRA on the shrinkage properties of the M-S-H cement system was evaluated. The mechanism of SRA was investigated by surface tension measurement, hydration heat testing, thermogravimetric analysis, and pore structure analysis. Experimental results indicate that SRA can reduce the shrinkage of the M-S-H mortar, and the optimal effect is exerted when the dosage is 3.0%, drying shrinkage decreases by 22.6%, and autogenous shrinkage decreases by 60% on day 28. However, it may also adversely affect strength development. The presence of SRA in M-S-H cement can reduce pore solution surface tension, delay hydration, and maintain relative humidity within the slurry, which can be maintained at 82.0% on day 28. It can also increase pore size and porosity. The inhibitory effect of SRA on the shrinkage of M-S-H mortar is valuable for its future practical applications. Full article

(This article belongs to the Topic Green Low-Carbon Technology for Metalliferous Minerals)

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15 pages, 27418 KiB

Open AccessArticle

Multiple-Stage Neoproterozoic Magmatism Recorded in the Zhangbaling Uplift of the Northeastern Yangtze Block: Evidence from Zircon Ages and Geochemistry

by Jing Wang, Jun He, Jingxin Zhao, Yizeng Yang and Fukun Chen

Minerals 2023, 13(4), 562; https://doi.org/10.3390/min13040562 - 17 Apr 2023

Cited by 3 | Viewed by 1343

Abstract

The Yangtze Block records Neoproterozoic magmatism and sedimentation related to the breakup of Rodinia and is an important piece in the reconstruction of the supercontinent. However, the tectonic setting and position of this block in Rodinia remain a subject of debate. In the [...] Read more.

The Yangtze Block records Neoproterozoic magmatism and sedimentation related to the breakup of Rodinia and is an important piece in the reconstruction of the supercontinent. However, the tectonic setting and position of this block in Rodinia remain a subject of debate. In the present study, we report the zircon U-Pb ages and Hf isotopic composition of zircon and geochemical and Nd-Pb isotopic compositions for meta-volcanic rocks exposed in the Zhangbaling uplift of the NE Yangtze Block. The volcanic rocks, dominated by rhyolite and dacite, belong to the calc-alkaline series and show geochemical characteristics of arc rocks. Zircon U-Pb isotopic ages show that volcanic rocks in the Xileng Formation formed at ca. 790 Ma and ca. 760–700 Ma peaking at ~740 Ma. The late-stage volcanism was widely exposed in the uplift, characterized by a temporal-spatial trend becoming younger southwards. The old volcanic rocks have low initial ε_Nd (−11.0) and ε_Hf (−19.7 to −8.2) values and low Pb isotopic ratios, likely indicating an origin from ancient basement rocks underneath the Yangtze Block. The younger ones, being similar to continental arc andesite in trace element compositions, have relatively high initial ε_Nd (mostly −4.6 to 0.5) and ε_Hf (−0.4 to 8.8) values and high Pb isotopic ratios. These isotopic features point to an origin from the partial melting of juvenile crustal rocks. Sedimentary rocks of the Xileng Formation and the overlying strata also contain numerous zircon grains of ~700 Ma to ~630 Ma. The volcanic rocks in the Zhangbaling uplift might demonstrate long-lasting subduction along the northeastern margin of the Yangtze Block, probably active until ca. 700 Ma. Full article

(This article belongs to the Special Issue Tectonic Evolution of Orogens: Metamorphic Petrology, Structural Geology, Geochronology and Geochemistry, Volume II)

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12 pages, 546 KiB

Open AccessOpinion

Proxy Archives Based on Marine Calcifying Organisms and the Role of Process-Based Biomineralization Concepts

by Gernot Nehrke and Gerald Langer

Minerals 2023, 13(4), 561; https://doi.org/10.3390/min13040561 - 17 Apr 2023

Cited by 1 | Viewed by 1678

Abstract

Proxy archives based on marine calcifying organisms and their element and isotope signatures represent valuable tools in the reconstruction of past climates. Despite the fact that the underlying biomineralization processes behind the measured signatures are poorly understood, these tools work remarkably well. However, [...] Read more.

Proxy archives based on marine calcifying organisms and their element and isotope signatures represent valuable tools in the reconstruction of past climates. Despite the fact that the underlying biomineralization processes behind the measured signatures are poorly understood, these tools work remarkably well. However, even though they work well many researchers felt the need to decipher the “black box” and understand the processes leading to the measured signatures. In this paper we assess how far we have come in understanding the biomineralization processes underpinning proxy signatures derived from marine calcifying organisms and how this understanding improved the way we use these proxy archives today. Biomineralization in the context of proxy research is an interdisciplinary field and cross-discipline communication can be challenging due to a lack of background in foreign disciplines. This often leads to misunderstanding and over- (or under-) estimation of certain concepts/methods/data. We, therefore, present a concise introduction to the topic, clarifying key concepts and their applicability to proxy interpretation. Full article

(This article belongs to the Special Issue Biomineralization of Organisms Used as Environmental Proxy Archives)

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16 pages, 7740 KiB

Open AccessArticle

Distribution and Genesis of Potassium-Bearing Minerals in Lop Nor Playa, Xinjiang, China

by Kai Wang, Yu Zhang, Jiahuan Han, Lichun Ma, Mianping Zheng, Yue Wu and Banwang Yang

Minerals 2023, 13(4), 560; https://doi.org/10.3390/min13040560 - 17 Apr 2023

Cited by 3 | Viewed by 1772

Abstract

Lop Nor Playa is the main salt-forming area in the Tarim Basin, which is rich in brine resources. There is a large amount of potassium fertilizer produced from potassium-rich brine in Lop Nor annually, which meets about half of the demands of China’s [...] Read more.

Lop Nor Playa is the main salt-forming area in the Tarim Basin, which is rich in brine resources. There is a large amount of potassium fertilizer produced from potassium-rich brine in Lop Nor annually, which meets about half of the demands of China’s agricultural potash, along with that produced in the Qaidam Basin. In order to investigate the distribution characteristics of potassium-bearing minerals and the origin of potassium-bearing salts in Lop Nor Playa, mineralogy and hydrogeochemistry studies were carried out. The results showed that there are a large number of polyhalite layers distributed in the Luobei Depression and Xinqing Platform. Brines with high content of K⁺ and Mg²⁺ have reactions with calcium sulfate minerals, generating secondary polyhalite layers. Carnallite layers are mainly distributed in subbasins along fault zones in all three mining areas with small size. Ca-Cl-type waters rise to the surface along fault zones and mix with ground water as soon as they appear on the ground, forming the deposits of carnallite and bischofite after evaporation. During the generation of potassic salts, fault zones, on the one hand, control the margin of mining areas and the distribution of polyhalite layers. On the other hand, they act as the migration and reaction space for salt spring water, providing large amounts of ore-forming elements such as Ca²⁺, K⁺, and Mg²⁺. This study provides a theoretical basis for the exploration of potassium-rich brine in the Lop Nor Basin. Full article

(This article belongs to the Special Issue Geochemical Exploration for Critical Mineral Resources)

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17 pages, 4142 KiB

Open AccessArticle

Calcium Sulfate Crystallization in Presence of Fluorecent-Tagged Polyacrylate and Some Refinement of Scale Inhibition Mechanism

by Maria Trukhina, Sergey Tkachenko, Anastasia Ryabova, Maxim Oshchepkov, Anatoly Redchuk and Konstantin Popov

Minerals 2023, 13(4), 559; https://doi.org/10.3390/min13040559 - 17 Apr 2023

Cited by 8 | Viewed by 2362

Abstract

Deposits of calcium sulfate scale on the surfaces of industrial equipment in distillation facilities, reverse osmosis desalination plants, in oil and gas industries lead to significant clogging of pipes and membranes and to a serious increase in production costs. For the mitigation of [...] Read more.

Deposits of calcium sulfate scale on the surfaces of industrial equipment in distillation facilities, reverse osmosis desalination plants, in oil and gas industries lead to significant clogging of pipes and membranes and to a serious increase in production costs. For the mitigation of scale formation, the wide spectrum of antiscalants is applied. The present work is dedicated to the study of calcium sulfate deposition from supersaturated aqueous solutions in the presence of polyacrylic antiscalant with fluorescent marker (naphthalimide fragment) PAA-F1, which provides traceability of the scale inhibitor and a better understanding of its efficacy. A paradoxical phenomenon is being described here. Antiscalant causes a change in the crystal phase from bassanite to gypsum, significantly reduces the amount of deposit, but does not reveal the presence of its molecules either at the kink, step, or at selected edge sites of deposited crystals. Contrary to the predictions of the theory, it either stays in the aqueous phase, or forms its own separate phase Ca-PAA-F1. It is demonstrated that the antiscalant does not block the surfaces of calcium sulfate nuclei or crystal surfaces, but rather the foreign particles of nanodust with particle sizes around 1 nm, naturally occurring in any aqueous solution. As a result, the number of calcium nucleation sites is reduced, and the rate of scale formation decreases without any apparent antiscalant–scale interaction. On the grounds of the current experiment, the substoichiometric effect of scale inhibition obtained an alternative, quite stoichiometric explanation. Full article

(This article belongs to the Special Issue Sulphate and Carbonate Minerals)

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10 pages, 6379 KiB

Open AccessFeature PaperArticle

Mineral Phase Evolution during Oxidation Roasting Pretreatment of Typical Carlin Gold Ore and Effects on Gold Leaching Efficiency

by Licheng Ma, Xiang Liu, Lei Wang and Jungang Qi

Minerals 2023, 13(4), 558; https://doi.org/10.3390/min13040558 - 16 Apr 2023

Cited by 1 | Viewed by 2186

Abstract

Arsenious and sulphur-bearing micro-disseminated gold ore is a kind of typical refractory Carlin-Type. The gold in Carlin-Type gold ore grains is distributed finely, existing as invisible or submicroscopic gold, encapsulated in arsenopyrite and pyrite. The technical difficulty of treatment Carlin-Type gold ore lies [...] Read more.

Arsenious and sulphur-bearing micro-disseminated gold ore is a kind of typical refractory Carlin-Type. The gold in Carlin-Type gold ore grains is distributed finely, existing as invisible or submicroscopic gold, encapsulated in arsenopyrite and pyrite. The technical difficulty of treatment Carlin-Type gold ore lies in how to release the fine gold wrapped in pyrite and arsenopyrite. In this study, the oxidation roasting pre-treatment technique was used to treat the Carlin-Type gold ore. This included a two-stage roasting process: the arsenic was removed in the first roasting process, and the sulphur was removed in the second roasting process. The thermodynamic of the roasting process was analyzed, and the mineral phase evolution of the roasting process was investigated by using XRD, SEM and EDS. Finally, the influence of sodium cyanide dosage and leaching time on leaching efficiency was investigated. The results suggest that for the first roasting temperature at 550 °C, and the second roasting at temperature 700 °C with air flow 2.5 L/min, the sodium cyanide dosage is 1.75 kg/t and leaching time is 27 h; a good leaching efficiency is obtained with 83.85%. Full article

(This article belongs to the Special Issue Valuable Metals Recovery by Mineral Processing and Hydrometallurgy)

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17 pages, 7962 KiB

Open AccessArticle

Petrogenesis and Tectonic Significance of Late Triassic A₁-Type Granite from the West Section of North Qinling Orogenic Belt: Constraints from Geochronology and Geochemistry

by Shang Ji, Zuochen Li, Xianzhi Pei, Lei Pei, Ruibao Li, Chengjun Liu, Youxin Chen, Hao Lin and Mao Wang

Minerals 2023, 13(4), 557; https://doi.org/10.3390/min13040557 - 16 Apr 2023

Cited by 2 | Viewed by 1725

Abstract

The North China Block and the South China Block collided in the Middle Triassic, but there is still a lack of consensus regarding the end of collisional orogeny and the closure time of the Paleo-Tethys. In this paper, we report zircon U–Pb ages [...] Read more.

The North China Block and the South China Block collided in the Middle Triassic, but there is still a lack of consensus regarding the end of collisional orogeny and the closure time of the Paleo-Tethys. In this paper, we report zircon U–Pb ages and geochemistry for the Shimen pluton in the northern margin of the West Qinling Orogenic Belt to investigate its genesis and tectonic environment. The new findings allow to constrain the end time of the Triassic orogeny in the Qinling Orogenic Belt and the closure time of the Paleo-Tethys. The weighted average ²⁰⁶Pb/²³⁸U ages of the Shimen pluton are 218.6 ± 1.5 Ma and 221.0 ± 1.7 Ma. Thus, we suggest that the Shimen pluton crystallized at the 218.6 Ma and 221.0 Ma and was formed during the Late Triassic (Norian). The Shimen pluton is mainly syenogranite and has alkaline dark minerals aegirine–augite. It is composed of 73.45 to 77.80 wt.% SiO₂, 8.28 to 9.76 wt.% alkali, and 11.35 to 13.58 wt.% Al₂O₃, with A/CNK ranging from 0.91 to 1.02 and 10,000 Ga/Al ranging from 2.39 to 3.15. These findings indicate that the Shimen pluton is typical A-type granite. The plutons have low rare earth element contents, ranging from 73.92 to 203.58 ppm, with a moderate negative Eu anomaly. All the samples are enriched in large-ion lithophile elements, such as Rb, Nd, Th and U, and light rare earth elements, and are depleted in high field strength elements, such as Nb, P, Zr, Ba, and Sr. The depletion of Ba, Sr, and Zr may be related to the fractionation and evolution of the granite. According to the petrological and geochemical characteristics, the Shimen pluton is an A₁-type granite formed in an anorogenic extensional environment. Combined with its tectonic characteristics and petrogenesis, the Shimen pluton was probably formed by the partial melting of the crust under high temperature and low pressure in the intraplate environment after the subduction of the South China Block beneath the North China Block. This observation indicates that the Triassic orogeny in the Qinling Orogenic Belt had ended and the Paleo-Tethys-Mianlve Ocean had also closed by the Late Triassic (Norian). Full article

(This article belongs to the Special Issue Petrology, Geochemistry and Isotopes of Ophiolite and Granites in Kunlun Orogen and Adjacent Area)

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17 pages, 5145 KiB

Open AccessArticle

In Situ Mineralogical Constraints on Magmatic Process for Porphyry Deposits in the Upper Crust: A Case from Tongchang–Chang’anchong Porphyry Deposits, SW China

by Zixuan Wang, Yuanchuan Zheng, Bo Xu, Yang Shen and Lu Wang

Minerals 2023, 13(4), 556; https://doi.org/10.3390/min13040556 - 15 Apr 2023

Viewed by 2228

Abstract

The magmatic process within upper crust encompasses various contents such as the transition between magmatic and hydrothermal systems and changes in oxygen fugacity (ƒO₂), which ultimately play key roles in the formation of porphyry Cu deposits (PCDs). However, tracing these magmatic [...] Read more.

The magmatic process within upper crust encompasses various contents such as the transition between magmatic and hydrothermal systems and changes in oxygen fugacity (ƒO₂), which ultimately play key roles in the formation of porphyry Cu deposits (PCDs). However, tracing these magmatic processes, especially in porphyry systems, is not an easy task. This study reported the detailed process of magmatic fluid exsolution and systematical variation of magmatic ƒO₂ within the upper crust of a Tongchang–Chang’anchong porphyry Cu deposit, based on detailed investigations of mineral crystallization sequences and compositional features of the minerals in the fertile porphyries. Results indicate that the fertile porphyries show a high initial ƒO₂, with ΔFMQ ≥ +3.0 (ΔFMQ is the deviation of logƒO₂ from the fayalite–magnetite–quartz (FMQ) buffer). The magmatic ƒO₂ (ΔFMQ) continued to decrease to ~+2 until fluid exsolution occurred at ~790 °C due to wall-rock contamination. The magmatic fluid exsolution process caused a temporary increase in the ƒO₂ (to ΔFMQ = ~+3.4). The high magmatic ƒO₂ during this process (790–750 °C) resulted in a higher content of ore-forming materials in the exsolved magmatic fluid. When the temperature dropped below 750 °C, the magmatic ƒO₂ began to continuously decrease and eventually reached ΔFMQ = ~+0.6. The lower magmatic ƒO₂ hindered the further migration of ore-forming materials through the exsolved fluid during this process (< 750 °C). Results of this study indicate that the initial magma during the upper crustal magmatic process of PCDs generally has a high ƒO₂, and the contamination of reduced components can significantly decrease the magmatic ƒO₂. The early magmatic fluid exsolution process can maintain a high magmatic ƒO₂ condition, thereby efficiently extracting ore-forming minerals and producing ore-forming fluids, which is the key to the formation of PCDs. The latter continuous decrease in magmatic ƒO₂ during the fluid exsolution process may be the reason preventing the Tongchang–Chang’anchong porphyry Cu deposit to form a giant PCD. Full article

(This article belongs to the Section Mineral Deposits)

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38 pages, 40864 KiB

Open AccessFeature PaperArticle

Polymetallic Uranium Mineralisation in Rohil, Rajasthan, Western India: Insights from Mode of Occurrences, Structural Controls, Alteration Geochemistry and Exploration

by Ajoy Kumar Padhi, Mrinal Kanti Mukherjee, Brajesh Kumar Tripathi, Dheeraj Pande, Balbir Singh Bisht and Bhabesh Chandra Sarkar

Minerals 2023, 13(4), 555; https://doi.org/10.3390/min13040555 - 14 Apr 2023

Cited by 2 | Viewed by 3066

Abstract

Geological and radiometric studies of outcrops aided by extensive subsurface exploration through drill holes in an otherwise soil-covered terrain revealed the existence of low grades, medium tonnage, and metasomatite types of polymetallic uranium deposits at Rohil in India. Microscopic studies, electronprobe micro analyses, [...] Read more.

Geological and radiometric studies of outcrops aided by extensive subsurface exploration through drill holes in an otherwise soil-covered terrain revealed the existence of low grades, medium tonnage, and metasomatite types of polymetallic uranium deposits at Rohil in India. Microscopic studies, electronprobe micro analyses, and geochemical analyses of samples from lodes indicate the polymetallic nature of mineralisation involving copper and molybdenum, in addition to uranium. Wide variations in the composition of fluid (S-, F-, P-, and O-rich) led to the formation of sulphides, fluorite, U-phosphosilicate, quartz, and magnetite, respectively, and are associated with uraninite. Litho-geochemical analyses from the Rohil deposit indicate multifarious metasomatic alterations associated with polymetallic mineralisation occurring in veins. The major mineralogical and metasomatic controls on rock compositions and the extent of material transfer processes that influenced the host rocks and mineralisati on are quantified by molar element ratio studies and alteration plots. General element ratio (GER) diagrams on chemical analyses of rock samples reveal albitisation and chloritisation as major and microclinisation, sericitisation, carbonatisation, and silicification as minor wall rock alterations associated with ore mineralisation. The alteration box plot between the chlorite–carbonate–pyrite index (CCPI) and the Ishikawa alteration index (AI) indicates the influence of hydrothermal activity and dominance of both albitisation and chloritisation. The ore zone is controlled by meso- and microstructures and the geometry of the soda- and potash-metasomatised zone around hydrothermal veins. This zone contains several anastomosing mineralised veins defined by a prominent joint that is set in quartzite that strikes subparallel to the axial surface of the F₂ isoclinal folds and the pervasive schistosity S₁ in the quartz–feldspar–biotite schist. Aventurisation of albite and microcline, established through electron probe micro analyses, can be considered as a pathfinder for uranium mineralisation. The close association of uranium and metallic sulphide mineralisation with microstructural, mineralogical (albitisation, chloritisation, and microclinisation), and geochemical variations can be applied as suitable exploration guides in a similar geological set-up worldwide. Full article

(This article belongs to the Special Issue Economic Mineral Deposits: A Review)

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15 pages, 4384 KiB

Open AccessArticle

Rare Earth Occurrence States of Weathered Crust Elution-Deposited Rare Earth Ores in Southern Yunnan

by Wendou Chen, Zhenyue Zhang, Fei Long, Zhuo Chen and Ru’an Chi

Minerals 2023, 13(4), 554; https://doi.org/10.3390/min13040554 - 14 Apr 2023

Cited by 6 | Viewed by 1999

Abstract

To reveal the regularity of variation in the rare earth occurrence states of weathered crust elution-deposited rare earth ores, ore samples from different weathering crust layers were obtained by performing the sequential extraction procedure. The order of rare earth contents firmly obeyed the [...] Read more.

To reveal the regularity of variation in the rare earth occurrence states of weathered crust elution-deposited rare earth ores, ore samples from different weathering crust layers were obtained by performing the sequential extraction procedure. The order of rare earth contents firmly obeyed the following sequence: the weathered layer > humic layer > partly weathered layer. The occurrence states of rare earth elements were mainly the ion exchange state, carbonate bound state, iron–manganese oxide state, organic binding state and residual state. The proportions of rare earth elements found in the rare earth ion exchange state of the weathered layer, humic layer and partly weathered layer were 78.55%, 73.53% and 53.88%, respectively. The light rare earth elements (LREEs) found in the rare earth ion exchange state were enriched in the upper part of the weathering crust, while the heavy rare earth elements (HREEs) were enriched in the lower part. There were also obvious negative anomalies in the content of cerium in the ion exchange state. The content of rare earth elements found in the carbonate bound state was small, and the rare earth partition pattern was basically consistent with that of the ion exchange state, which had little effect on the differentiation of the rare earth elements. The iron–manganese oxide state was mainly enriched with cerium, and the content of cerium increased with the depth of the weathering crust. The iron–manganese oxide state was the main factor causing the phenomenon of the anomaly in the cerium content. Meanwhile, the iron oxides in the iron–manganese oxide state were mainly hematite and goethite. The organic binding state mainly beneficiated yttrium and cerium by complexation and certain adsorption. The content of elements found in the rare earth residual state was related to the degree of weathering and reflected the release sequence of rare earth elements in the mineralization process. Clarifying the rare earth occurrence states is conducive to better revealing the metallogenic regularity of weathered crust elution-deposited rare earth ores. In addition, the results can provide a valuable reference for expanding the available rare earth resources and the efficient comprehensive utilization of rare earth ore. Full article

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

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Minerals, Volume 13, Issue 4 (April 2023) – 130 articles

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