Minerals

25 pages, 9543 KiB

Open AccessArticle

Chemical Composition and Genesis Implication of Garnet from the Laoshankou Fe-Cu-Au Deposit, the Northern Margin of East Junggar, NW China

by Pei Liang, Yu Zhang and Yuling Xie

Minerals 2021, 11(3), 334; https://doi.org/10.3390/min11030334 - 23 Mar 2021

Cited by 4 | Viewed by 3359

Abstract

In order to reveal the formation mechanism of different garnets and its implications for the fluid evolution in the Laoshankou Fe-Cu-Au deposit in the northern margin of East Junggar (NW China), three types of garnet have been investigated in detail in this study. [...] Read more.

In order to reveal the formation mechanism of different garnets and its implications for the fluid evolution in the Laoshankou Fe-Cu-Au deposit in the northern margin of East Junggar (NW China), three types of garnet have been investigated in detail in this study. (1) Type 1 grossular, formed at Ca-silicate stage (stage I, the pre-mineralization stage), was replaced by Type 2 garnet and magnetite, and displays a compositional range of Grs_44–53Adr_44–53, which has relatively lower total REE (rare earth elements) contents (8.14–32.8 ppm) and markedly depleted LREE (light rare earth elements) with distinctive positive Eu anomaly (1.36–9.61). (2) Type 2 Al-rich andradite, formed at the early sub-stage of amphibole-epidote-magnetite stage (stage II, the main magnetite mineralization stage), can be divided into two sub-types, i.e., Type 2a and Type 2b. Type 2a garnets exhibit polysynthetic twinning and relatively narrow compositional variations of Adr_63–66Grs_31–34 with HREE-(heavy rare-earth elements) enrichment and positive Eu anomalies (3.22–3.69). Type 2b garnets own wide compositional variations of Adr_55–77Grs_21–43 with relatively higher REE contents (49.1–124 ppm), markedly depleted LREE and a distinctive positive Eu anomaly (2.11–4.61). (3) Type 3 andradite (Adr_>91) associated with sulfide stage (stage III, the main copper-gold mineralization stage) is different from other types of garnets in Laoshankou, which are characterized by lowest total REE contents (1.66–91.1 ppm), flat HREE patterns, LREE-enrichment and the strongest positive Eu anomalies (3.31–45.48). Incorporation of REE into garnet is largely controlled by external factors, such as fluid chemistry, pH, ƒO₂ and water-rock ratios as well as its crystal chemistry. Type 1 and 2 garnets mainly follow the creation of X²⁺ (e.g., Ca²⁺) site vacancy, e.g.,

{[X^{2 +}]}_{- 3}^{V I I I} {[]}_{+ 1}^{V I I I} {[R E E^{3 +}]}_{+ 2}^{V I I I}

. The REE³⁺ substitution mechanism for Type 3 garnet is the Na⁺-REE³⁺ coupled substitutions, e.g.,

{[X^{2 +}]}_{- 2}^{V I I I} {[X^{+}]}_{+ 1}^{V I I I} {[R E E^{3 +}]}_{+ 1}^{V I I I}

, without the evaluation of the creation of site vacancy. The compositional variations from Type 1 to Type 3 garnet indicate significant differences of fluid compositions and physicochemical conditions, and can be used to trace the fluid–rock interaction and hydrothermal evolution of garnet. Type 1 grossular was formed by magmatic fluid under low water–rock ratios and ƒO₂, and neutral pH environment by diffusion metasomatism in a nearly closed system with the preferential incorporation into the grossular of HREE. As the long fluid pore residence and continuing infiltration metasomatism under nearly closed-system conditions, fluids with high water/rock ratios were characterized by increased ƒO₂, more active incorporation of Fe³⁺ and REE, and formed Type 2 Al-rich andradite. In contrast, Type 3 garnet formed by oxidizing magmatic fluid under a mildly acidic environment with highest ƒO₂ and water–rock ratios, and was influenced by externally derived high salinity and Ca-rich fluids in an open system. Thus, the geochemical features of different types and generations of garnets in the Laoshankou deposit can provide important information of fluid evolution, revealing a transition from neutral magmatic fluid to oxidizing magmatic fluid with addition of external non-magmatic Ca-rich fluid from the Ca-silicate stage to the sulfide stage. The above proved the fluid evolution process further indicates that the Laoshankou deposit prefers to be an IOCG-like (iron oxide-copper-gold) deposit rather than a typical skarn deposit. Full article

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18 pages, 3464 KiB

Open AccessArticle

The Rare Trachyandesitic Lavas at Mount Etna: A Case Study to Investigate Eruptive Process and Propose a New Interpretation for Magma Genesis

by Gabriele Lanzafame, Federico Casetta, Pier Paolo Giacomoni, Massimo Coltorti and Carmelo Ferlito

Minerals 2021, 11(3), 333; https://doi.org/10.3390/min11030333 - 23 Mar 2021

Cited by 2 | Viewed by 2697

Abstract

The growth of Mount Etna volcano reflects the superimposition of various eruptive centers, the most voluminous of which is the Ellittico, whose stratigraphic sequence is well exposed on the steep walls of Valle del Bove. The uppermost levels of the sequence have been [...] Read more.

The growth of Mount Etna volcano reflects the superimposition of various eruptive centers, the most voluminous of which is the Ellittico, whose stratigraphic sequence is well exposed on the steep walls of Valle del Bove. The uppermost levels of the sequence have been sampled and investigated through a new set of geochemical data on mineral phases and bulk rock. Sampled rocks display a marked bimodality with aphyric banded trachyandesites, which are some of the most evolved and rare products of the entire Etnean succession (SiO₂ 58–60 wt.%), intercalated in plagioclase rich porphyritic mugearites (SiO₂ 49–50 wt.%, P.I. 35–40). In this paper, we provide a detailed textural, mineralogical, and chemical characterization of these products, providing a new interpretative model for their genesis and significance in the context of the Etnean system. Our approach discusses, in a critical way, the “classic” fractional crystallization model of magmas, not supported by field evidence, and proposes a novel hypothesis in which the aphyric-banded trachyandesites represent be the primary products of a gas-induced partial melting of hypabyssal sills and dykes. This hypothesis represents a step towards a comprehensive description of igneous systems that takes into account not exclusively the evolution of basaltic melts, but also the role of volatile contributions in governing volcanic behavior. Full article

(This article belongs to the Special Issue Magma Ascent and Evolution: Insights from Petrology and Geochemistry)

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39 pages, 5137 KiB

Open AccessReview

Mullite-Based Ceramics from Mining Waste: A Review

by Maximina Romero, Isabel Padilla, Manuel Contreras and Aurora López-Delgado

Minerals 2021, 11(3), 332; https://doi.org/10.3390/min11030332 - 23 Mar 2021

Cited by 30 | Viewed by 6174

Abstract

Mullite (3Al₂O₃·2SiO₂) is an aluminosilicate characterized by excellent physical properties, which makes it an important ceramic material. In this way, ceramics based on mullite find applications in different technological fields as refractory material (metallurgy, glass, ceramics, etc.), [...] Read more.

Mullite (3Al₂O₃·2SiO₂) is an aluminosilicate characterized by excellent physical properties, which makes it an important ceramic material. In this way, ceramics based on mullite find applications in different technological fields as refractory material (metallurgy, glass, ceramics, etc.), matrix in composite materials for high temperature applications, substrate in multilayer packaging, protective coatings, components of turbine engines, windows transparent to infrared radiation, etc. However, mullite is scarce in nature so it has to be manufactured through different synthesis methods, such as sintering, melting-crystallization or through a sol-gel route. Commonly, mullite is fabricated from pure technical grade raw materials, making the manufacturing process expensive. An alternative to lowering the cost is the use of mining waste as silica (SiO₂) and alumina (Al₂O₃) feedstock, which are the necessary chemical compounds required to manufacture mullite ceramics. In addition to the economic benefits, the use of mining waste brings out environmental benefits as it prevents the over-exploitation of natural resources and reduces the volume of mining waste that needs to be managed. This article reviews the scientific studies carried out in order to use waste (steriles and tailings) generated in mining activities for the manufacture of clay-based ceramic materials containing mullite as a main crystalline phase. Full article

(This article belongs to the Special Issue Mining Waste as Raw Materials for Mullite-Based Ceramics)

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22 pages, 5126 KiB

Open AccessArticle

Identification and Geological Significance of Early Jurassic Adakitic Volcanic Rocks in Xintaimen Area, Western Liaoning

by Zhi-Wei Song, Chang-Qing Zheng, Chen-Yue Liang, Bo Lin, Xue-Chun Xu, Quan-Bo Wen, Ying-Li Zhao, Cheng-Gang Cao and Zhi-Xin Wang

Minerals 2021, 11(3), 331; https://doi.org/10.3390/min11030331 - 23 Mar 2021

Cited by 5 | Viewed by 2304

Abstract

The Western Liaoning area, where a large number of Jurassic-Cretaceous volcanic rocks are exposed, is one of the typical areas for studying the Mesozoic Paleo-Pacific and Mongolia-Okhotsk subduction process, and lithospheric destruction of North China Craton. The identification and investigation of Early Jurassic [...] Read more.

The Western Liaoning area, where a large number of Jurassic-Cretaceous volcanic rocks are exposed, is one of the typical areas for studying the Mesozoic Paleo-Pacific and Mongolia-Okhotsk subduction process, and lithospheric destruction of North China Craton. The identification and investigation of Early Jurassic adakitic volcanic rocks in the Xintaimen area of Western Liaoning is of particular significance for exploring the volcanic magma source and its composition evolution, tracking the crust-mantle interaction, and revealing the craton destruction and the subduction of oceanic plates. Detailed petrography, zircon U–Pb dating, geochemistry, and zircon Hf isotope studies indicate that the Early Jurassic intermediate-acidic volcanic rocks are mainly composed of trachydacites and a few rhyolites with the formation ages of 178.6–181.9 Ma. Geochemical characteristics show that they have a high content of SiO₂, MgO, Al₂O₃, and total-alkali, typical of the high-K calc-alkaline series. They also show enrichment of light rare earth elements (LREEs) and large ion lithophile elements (LILEs), depletion of heavy rare earth elements (HREEs) and high field strength elements (HFSEs), and have a high content of Sr and low content of Y and Yb, suggesting that they were derived from the partial melting of the lower crust. The ε_Hf(t) values of dated zircons and two-stage model ages (T_DM2) vary from −11.6 to −7.4 and from 1692 to 1958 Ma, respectively. During the Early Jurassic, the study area was under long-range tectonic effects with the closure of the Mongolia-Okhotsk Ocean and the subduction of the Paleo-Pacific plate, which caused the basaltic magma to invade the lower crust of the North China Craton. The mantle-derived magma was separated and crystallized while heating the Proterozoic lower crust, and part of the thickened crust melted to form these intermediate-acidic adakitic volcanic rocks. Full article

(This article belongs to the Special Issue Isotope Dating and Geochemistry of Granite)

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14 pages, 5525 KiB

Open AccessArticle

Pollution Characteristics, Distribution and Ecological Risk of Potentially Toxic Elements in Soils from an Abandoned Coal Mine Area in Southwestern China

by Libo Pan, Xiao Guan, Bo Liu, Yanjun Chen, Ying Pei, Jun Pan, Yi Zhang and Zhenzhen Hao

Minerals 2021, 11(3), 330; https://doi.org/10.3390/min11030330 - 22 Mar 2021

Cited by 12 | Viewed by 2962

Abstract

Acid mine drainage (AMD) from abandoned coal mines can lead to serious environmental problems due to its low pH and high concentrations of potentially toxic elements. In this study, soil pH, sulfur (S) content, and arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), [...] Read more.

Acid mine drainage (AMD) from abandoned coal mines can lead to serious environmental problems due to its low pH and high concentrations of potentially toxic elements. In this study, soil pH, sulfur (S) content, and arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), zinc (Zn), iron (Fe), manganese (Mn), and mercury (Hg) concentrations were measured in 27 surface soil samples from areas in which coal-mining activities ceased nine years previously in Youyu Catchment, Guizhou Province, China. The soil was acidic, with a mean pH of 5.28. Cadmium was the only element with a mean concentration higher than the national soil quality standard. As, Cd, Cu, Ni, Zn, Mn, Cr, and Fe concentrations were all higher than the background values in Guizhou Province. This was especially true for the Cd, Cu, and Fe concentrations, which were 1.69, 1.95, and 12.18 times their respective background values. The geoaccumulation index of Cd and Fe was present at unpolluted to moderately polluted and heavily polluted levels, respectively, indicating higher pollution levels than for the other elements in the study area. Spatially, significantly high Fe and S concentrations, as well as extremely low pH values, were found in the soils of the AMD sites; however, sites where tributaries merged with the Youyu River (TM) had the highest Cd pollution level. Iron originated mainly from non-point sources (e.g., AMD and coal gangues), while AMD and agricultural activity were the predominant sources of Cd. The results of an eco-risk assessment indicated that Cd levels presented a moderate potential ecological risk, while the other elements all posed a low risk. For the TM sites, the highest eco-risk was for Cd, with levels that could be harmful for aquatic organisms in the wet season, and may endanger human health via the food chain. Full article

(This article belongs to the Special Issue Elemental Concentration and Pollution in Soil, Water, and Sediment)

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21 pages, 5781 KiB

Open AccessArticle

Origin of Ru-Os Sulfides from the Verkh-Neivinsk Ophiolite Massif (Middle Urals, Russia): Compositional and S-Os Isotope Evidence

by Kreshimir N. Malitch, Inna Yu. Badanina, Elena A. Belousova, Valery V. Murzin and Tatiana A. Velivetskaya

Minerals 2021, 11(3), 329; https://doi.org/10.3390/min11030329 - 22 Mar 2021

Cited by 5 | Viewed by 2584

Abstract

This study presents new compositional and S-Os isotope data for primary Ru-Os sulfides within a platinum-group mineral (PGM) assemblage from placer deposits associated with the Verkh-Neivinsk massif, which is part of the mantle ophiolite association of Middle Urals (Russia). The primary nature of [...] Read more.

This study presents new compositional and S-Os isotope data for primary Ru-Os sulfides within a platinum-group mineral (PGM) assemblage from placer deposits associated with the Verkh-Neivinsk massif, which is part of the mantle ophiolite association of Middle Urals (Russia). The primary nature of Ru-Os sulfides represented by laurite (RuS₂)–erlichmanite (OsS₂) series is supported by occurrence of euhedral inclusions of high-Mg olivine (Fo_92–94) that fall within the compositional range of mantle (primitive) olivine (Fo _88–93). The sulfur isotope signatures of Ru-Os sulfides reveal a range of δ³⁴S values from 0.3 to 3.3‰, with a mean of 2.05‰ and a standard deviation of 0.86‰ (n = 18), implying that the sulfur derived from a subchondritic source. A range of sub-chondritic initial ¹⁸⁷Os/¹⁸⁸Os values defined for Ru-Os sulfides (0.1173–0.1278) are clearly indicative of derivation from a sub-chondritic source. Re-depletion (T_RD) ages of the Verkh-Neivinsk Ru-Os sulfides are consistent with prolonged melt-extraction processes and likely multi-stage evolution of highly siderophile elements (HSE) within the upper mantle. A single radiogenic ¹⁸⁷Os/¹⁸⁸Os value of 0.13459 ± 0.00002 determined in the erlichmanite is indicative of a supra-chondritic source of HSE. This feature can be interpreted as evidence of a radiogenic crustal component associated with a subduction event or as an indication of an enriched mantle source. The mineralogical and Os-isotope data point to a high-temperature origin of the studied PGM and two contrasting sources for HSE in Ru-Os sulfides of the Verkh-Neivinsk massif. Full article

(This article belongs to the Special Issue New Insights into Composition of the Earth’s Mantle Deduced from Osmium Isotope Data in Os-Rich Alloys, Sulfides, and Chromite)

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13 pages, 3050 KiB

Open AccessArticle

The Effect of Hydrodynamic Conditions on the Selective Flotation of Fully Liberated Low Grade Copper-Nickel Ore

by Haresh Kumar, Kirsi Luolavirta, Saad Ullah Akram, Hassan Mehmood and Saija Luukkanen

Minerals 2021, 11(3), 328; https://doi.org/10.3390/min11030328 - 21 Mar 2021

Cited by 2 | Viewed by 2650

Abstract

Low grade sulfide ores are difficult to process due to their composite mineralogy and their fine grained dissemination with gangue minerals. Therefore, fine grinding of such ores becomes essential to liberate valuable minerals. In this research, selective flotation was carried out using two [...] Read more.

Low grade sulfide ores are difficult to process due to their composite mineralogy and their fine grained dissemination with gangue minerals. Therefore, fine grinding of such ores becomes essential to liberate valuable minerals. In this research, selective flotation was carried out using two pitched blade turbine impellers with diameters of 6 cm and 7 cm to float copper and nickel. The main focus of this research was to generate optimum hydrodynamic conditions that can effectively separate nickel and copper from gangue minerals. In addition, we investigated the effects of superficial gas velocity, impeller speed, bubble size distribution, and bubble surface area flux on the flotation recovery and rate constant. The results demonstrated that a 7 cm impeller comparatively produced optimum hydrodynamic conditions that improved Cu-Ni recovery and the rate constant. The maximum copper and nickel recoveries in the 7 cm impeller tests were observed at 93.1% and 72.5%, respectively. However, a significant decrease in the flotation rate of nickel was observed, due to entrainment of nickel in copper concentrate and the slime coating of gangue minerals on the nickel particle surfaces. Full article

(This article belongs to the Special Issue Process Optimization in Mineral Processing)

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20 pages, 5897 KiB

Open AccessArticle

Analysis of Spatial Variability of River Bottom Sediment Pollution with Heavy Metals and Assessment of Potential Ecological Hazard for the Warta River, Poland

by Joanna Jaskuła, Mariusz Sojka, Michał Fiedler and Rafał Wróżyński

Minerals 2021, 11(3), 327; https://doi.org/10.3390/min11030327 - 21 Mar 2021

Cited by 38 | Viewed by 4842

Abstract

Pollution of river bottom sediments with heavy metals (HMs) has emerged as a main environmental issue related to intensive anthropopressure on the water environment. In this context, the risk of harmful effects of the HMs presence in the bottom sediments of the Warta [...] Read more.

Pollution of river bottom sediments with heavy metals (HMs) has emerged as a main environmental issue related to intensive anthropopressure on the water environment. In this context, the risk of harmful effects of the HMs presence in the bottom sediments of the Warta River, the third longest river in Poland, has been assessed. The concentrations of Cr, Ni, Cu, Zn, Cd, and Pb in the river bottom sediments collected at 24 sample collection stations along the whole river length have been measured and analyzed. Moreover, in the GIS environment, a method predicting variation of HMs concentrations along the whole river length, not at particular sites, has been proposed. Analysis of the Warta River bottom sediment pollution with heavy metals in terms of the indices: the Geoaccumulation Index (Igeo), Enrichment Factor (EF), Pollution Load Index (PLI), and Metal Pollution Index (MPI), has proved that, in 2016, the pollution was heavier than in 2017. Assessment of the potential toxic effects of HMs accumulated in bottom sediments, made on the basis of Threshold Effect Concentration (TEC), Midpoint Effect Concentration (MEC), and Probable Effect Concentration (PEC) values, and the Toxic Risk Index (TRI), has shown that the ecological hazard in 2017 was much lower. Cluster analysis revealed two main groups of sample collection stations at which bottom sediments showed similar chemical properties. Changes in classification of particular sample collection stations into the two groups analyzed over a period of two subsequent years indicated that the main impact on the concentrations of HMs could have their point sources in urbanized areas and river fluvial process. Full article

(This article belongs to the Special Issue Elemental Concentration and Pollution in Soil, Water, and Sediment)

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15 pages, 6725 KiB

Open AccessArticle

REE and Sr–Nd Isotope Characteristics of Cambrian–Ordovician Carbonate in Taebaek and Jeongseon Area, Korea

by Tae-Hyeon Kim, Seung-Gu Lee and Jae-Young Yu

Minerals 2021, 11(3), 326; https://doi.org/10.3390/min11030326 - 21 Mar 2021

Cited by 1 | Viewed by 2455

Abstract

Carbonate formations of the Cambro-Ordovician Period occur in the Taebaek and Jeongseon areas, located in the central–eastern part of the Korean Peninsula. This study analyzed the rare earth element (REE) contents and Sr–Nd isotope ratios in these carbonates to elucidate their depositional environment [...] Read more.

Carbonate formations of the Cambro-Ordovician Period occur in the Taebaek and Jeongseon areas, located in the central–eastern part of the Korean Peninsula. This study analyzed the rare earth element (REE) contents and Sr–Nd isotope ratios in these carbonates to elucidate their depositional environment and diagenetic history. The CI chondrite-normalized REE patterns of the carbonates showed negative Eu anomalies (Eu_N/(Sm_N × Gd_N)^1/2 = 0.50 to 0.81), but no Ce anomaly (Ce/Ce* = Ce_N/(La_N² × Nd_N)^1/3 = 1.01 ± 0.06). The plot of log (Ce/Ce*) against sea water depth indicates that the carbonates were deposited in a shallow-marine environment such as a platform margin. The ⁸⁷Sr/⁸⁶Sr ratios in both Taebaek and Jeongseon carbonates were higher than those in the seawater at the corresponding geological time. The ⁸⁷Sr/⁸⁶Sr ratios and the values of (La/Yb)_N and (La/Sm)_N suggest that the carbonates in the areas experienced diagenetic processes several times. Their ¹⁴³Nd/¹⁴⁴Nd ratios varied from 0.511841 to 0.511980. The low ε_Nd values and high ⁸⁷Sr/⁸⁶Sr ratios in the carbonates may have resulted from the interaction with the hydrothermal fluid derived from the intrusive granite during the Cretaceous Period. Full article

(This article belongs to the Special Issue Rare Earth Elements and Their Isotope Geochemistry)

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22 pages, 2961 KiB

Open AccessFeature PaperArticle

Linear Structural Trends and Multi-Phase Intergrowths in Helvine-Group Minerals, (Zn,Fe,Mn)₈[Be₆Si₆O₂₄]S₂

by Sytle M. Antao

Minerals 2021, 11(3), 325; https://doi.org/10.3390/min11030325 - 20 Mar 2021

Cited by 4 | Viewed by 2124

Abstract

Synchrotron high-resolution powder X-ray diffraction (HRPXRD) and Rietveld structure refinements were used to examine the crystal structure of single phases and intergrowths (either two or three phases) in 13 samples of the helvine-group minerals, (Zn,Fe,Mn)₈[Be₆Si₆O₂₄]S [...] Read more.

Synchrotron high-resolution powder X-ray diffraction (HRPXRD) and Rietveld structure refinements were used to examine the crystal structure of single phases and intergrowths (either two or three phases) in 13 samples of the helvine-group minerals, (Zn,Fe,Mn)₈[Be₆Si₆O₂₄]S₂. The helvine structure was refined in the cubic space group

P \bar{4} 3 n

. For the intergrowths, simultaneous refinements were carried out for each phase. The structural parameters for each phase in an intergrowth are only slightly different from each other. Each phase in an intergrowth has well-defined unit-cell and structural parameters that are significantly different from the three endmembers and these do not represent exsolution or immiscibility gaps in the ternary solid-solution series. The reason for the intergrowths in the helvine-group minerals is not clear considering the similar radii, identical charge, and diffusion among the interstitial M cations (Zn²⁺, Fe²⁺, and Mn²⁺) that are characteristic of elongated tetrahedral coordination. The difference between the radii of Zn²⁺ and Mn²⁺ cations is 10%. Depending on the availability of the M cations, intergrowths may occur as the temperature, pressure, fugacity fS₂, and fluid composition change on crystallization. The Be–Si atoms are fully ordered. The Be–O and Si–O distances are nearly constant. Several structural parameters (Be–O–Si bridging angle, M–O, M–S, average <M–O/S>[4] distances, and TO₄ rotational angles) vary linearly with the a unit-cell parameter across the series because of the size of the M cation. Full article

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

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9 pages, 668 KiB

Open AccessReview

Amp-TB2: An Updated Model for Calcic Amphibole Thermobarometry

by Filippo Ridolfi

Minerals 2021, 11(3), 324; https://doi.org/10.3390/min11030324 - 20 Mar 2021

Cited by 63 | Viewed by 6397

Abstract

Amphibole (Amp) plays a crucial role in the study of several earth and planetary processes. One of its most common applications is in thermobarometry, especially for volcanic-magmatic systems. However, many thermobarometers require the input of melt composition, which is not always available in [...] Read more.

Amphibole (Amp) plays a crucial role in the study of several earth and planetary processes. One of its most common applications is in thermobarometry, especially for volcanic-magmatic systems. However, many thermobarometers require the input of melt composition, which is not always available in volcanic products (e.g., partially crystallized melts or devitrified glasses), or show rather high errors for characterizing the depth of magma chambers. In this work, a new version of amphibole thermobarometry based on the selection of recently published high-quality experimental data is reported. It is valid for Mg-rich calcic amphiboles in magmatic equilibrium with calc-alkaline or alkaline melts across a wide P-T range (up to 2200 MPa and 1130 °C) and presents the advantage of being a single-phase model with relatively low errors (P ±12%, T ±22 °C, logfO₂ ±0.3, H₂O in the melt ±14%). A user-friendly spreadsheet (Amp-TB2.xlsx) for calculating the physico-chemical parameters from the composition of natural amphiboles is also reported. It gives warnings whenever the input composition is incorrect or diverges from that of the calibration data and includes diagrams for an easy graphical representation of the results. Full article

(This article belongs to the Section Mineral Exploration Methods and Applications)

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18 pages, 4979 KiB

Open AccessEditor’s ChoiceArticle

The Binding of Phosphorus Species at Goethite: A Joint Experimental and Theoretical Study

by Prasanth B. Ganta, Mohsen Morshedizad, Oliver Kühn, Peter Leinweber and Ashour A. Ahmed

Minerals 2021, 11(3), 323; https://doi.org/10.3390/min11030323 - 20 Mar 2021

Cited by 10 | Viewed by 3923

Abstract

Knowledge of the interaction between inorganic and organic phosphates with soil minerals is vital for improving soil P-fertility. To achieve an in-depth understanding, we combined adsorption experiments and hybrid ab initio molecular dynamics simulations to analyze the adsorption of common phosphates, i.e., orthophosphate [...] Read more.

Knowledge of the interaction between inorganic and organic phosphates with soil minerals is vital for improving soil P-fertility. To achieve an in-depth understanding, we combined adsorption experiments and hybrid ab initio molecular dynamics simulations to analyze the adsorption of common phosphates, i.e., orthophosphate (OP), glycerolphosphate (GP) and inositolhexaphosphate (IHP), onto the 100 surface plane of goethite. Experimental adsorption data per mol P-molecule basis fitted to the Freundlich model show the adsorption strength increases in the order GP < OP < IHP, and IHP adsorption being saturated faster followed by GP and OP. Modeling results show that OP and GP form stable monodentate (M) and binuclear bidentate (B) motifs, with B being more stable than M, whereas IHP forms stable M and 3M motifs. Interfacial water plays an important role through hydrogen bonds and proton transfers with OP/GP/IHP and goethite. It also controls the binding motifs of phosphates with goethite. Combining both experimental and modeling results, we propose that the B motif dominates for OP, whereas GP forms M and IHP forms a combination of M and 3M motifs. The joint approach plausibly explains why IHP is the predominant organically bound P form in soil. This study could be considered as a preliminary step for further studies for understanding the mechanisms of how microbes and plants overcome strong IHP–mineral binding to implement the phosphate groups into their metabolism. Full article

(This article belongs to the Special Issue Recent Advances in Molecular Modeling of Clay Minerals Interfaces)

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17 pages, 3228 KiB

Open AccessArticle

Equations of State of Ca-Silicates and Phase Diagram of the CaSiO₃ System under Upper Mantle Conditions

by Tatiana S. Sokolova and Peter I. Dorogokupets

Minerals 2021, 11(3), 322; https://doi.org/10.3390/min11030322 - 19 Mar 2021

Cited by 9 | Viewed by 3215

Abstract

The equations of state of different phases in the CaSiO₃ system (wollastonite, pseudowollastonite, breyite (walstromite), larnite (Ca₂SiO₄), titanite-structured CaSi₂O₅ and CaSiO₃-perovskite) are constructed using a thermodynamic model based on the Helmholtz free energy. [...] Read more.

The equations of state of different phases in the CaSiO₃ system (wollastonite, pseudowollastonite, breyite (walstromite), larnite (Ca₂SiO₄), titanite-structured CaSi₂O₅ and CaSiO₃-perovskite) are constructed using a thermodynamic model based on the Helmholtz free energy. We used known experimental measurements of heat capacity, enthalpy, and thermal expansion at zero pressure and high temperatures, and volume measurements at different pressures and temperatures for calculation of parameters of equations of state of studied Ca-silicates. The used thermodynamic model has allowed us to calculate a full set of thermodynamic properties (entropy, heat capacity, bulk moduli, thermal expansion, Gibbs energy, etc.) of Ca-silicates in a wide range of pressures and temperatures. The phase diagram of the CaSiO₃ system is constructed at pressures up to 20 GPa and temperatures up to 2000 K and clarifies the phase boundaries of Ca-silicates under upper mantle conditions. The calculated wollastonite–breyite equilibrium line corresponds to equation P(GPa) = −4.7 × T(K) + 3.14. The calculated density and adiabatic bulk modulus of CaSiO₃-perovskite is compared with the PREM model. The calcium content in the perovskite composition will increase the density of mineral and it good agree with the density according to the PREM model at the lower mantle region. Full article

(This article belongs to the Special Issue Minerals and Solids at High Temperature and High Pressure: Equations of State and Thermodynamics)

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30 pages, 6216 KiB

Open AccessArticle

Stable Abiotic Production of Ammonia from Nitrate in Komatiite-Hosted Hydrothermal Systems in the Hadean and Archean Oceans

by Manabu Nishizawa, Takuya Saito, Akiko Makabe, Hisahiro Ueda, Masafumi Saitoh, Takazo Shibuya and Ken Takai

Minerals 2021, 11(3), 321; https://doi.org/10.3390/min11030321 - 19 Mar 2021

Cited by 10 | Viewed by 3334

Abstract

Abiotic fixation of atmospheric dinitrogen to ammonia is important in prebiotic chemistry and biological evolution in the Hadean and Archean oceans. Though it is widely accepted that nitrate (NO₃⁻) was generated in the early atmospheres, the stable pathways of ammonia [...] Read more.

Abiotic fixation of atmospheric dinitrogen to ammonia is important in prebiotic chemistry and biological evolution in the Hadean and Archean oceans. Though it is widely accepted that nitrate (NO₃⁻) was generated in the early atmospheres, the stable pathways of ammonia production from nitrate deposited in the early oceans remain unknown. This paper reports results of the first experiments simulating high-temperature, high-pressure reactions between nitrate and komatiite to find probable chemical pathways to deliver ammonia to the vent–ocean interface of komatiite-hosted hydrothermal systems and the global ocean on geological timescales. The fluid chemistry and mineralogy of the komatiite–H₂O–NO₃⁻ system show iron-mediated production of ammonia from nitrate with yields of 10% at 250 °C and 350 °C, 500 bars. The komatiite–H₂O–NO₃^– system also generated H₂-rich and alkaline fluids, well-known prerequisites for prebiotic and primordial metabolisms, at lower temperatures than the komatiite–H₂O–CO₂ system. We estimate the ammonia flux from the komatiite-hosted systems to be 10⁵–10¹⁰ mol/y in the early oceans. If the nitrate concentration in the early oceans was greater than 10 μmol/kg, the long-term production of ammonia through thermochemical nitrate reduction for the first billion years might have allowed the subsequent development of an early biosphere in the global surface ocean. Our results imply that komatiite-hosted systems might have impacted not only H₂-based chemosynthetic ecosystems at the vent-ocean interface but also photosynthetic ecosystems on the early Earth. Full article

(This article belongs to the Special Issue Expanding Views of Clays, Oxides, and Evaporites on Aquaplanets in the Solar System)

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21 pages, 2157 KiB

Open AccessArticle

Potential of Tailing Deposits in Chile for the Sequestration of Carbon Dioxide Produced by Power Plants Using Ex-Situ Mineral Carbonation

by Oscar Marín, José O. Valderrama, Andrzej Kraslawski and Luis A. Cisternas

Minerals 2021, 11(3), 320; https://doi.org/10.3390/min11030320 - 19 Mar 2021

Cited by 11 | Viewed by 4092

Abstract

In this study, the potential of copper tailing deposits in Chile for the sequestration of carbon dioxide (CO₂) via ex-situ mineral carbonation integrating the recovery of valuable metals was assessed. An inventory of tailing deposits and CO₂ sources existing in [...] Read more.

In this study, the potential of copper tailing deposits in Chile for the sequestration of carbon dioxide (CO₂) via ex-situ mineral carbonation integrating the recovery of valuable metals was assessed. An inventory of tailing deposits and CO₂ sources existing in Chile was constructed to determine the most suitable site for the installation of a future mineral carbonation plant and to evaluate the technical, economic, and environmental feasibility of CO₂ capture, separation, and transport from the source to the mineral carbonation plant. The data of the inventory of tailings deposits in Chile were obtained from the National Service of Geology and Mining. For the thermoelectric plants installed in Chile, data of energy production were obtained from the Energy National Commission. Through the use of the technique for order preference by similarity to ideal solution (TOPSIS) method and sensitivity analysis, the optimum location in the region of Antofagasta to install a mineral carbonation plant was identified. In addition, the results show that in the region of Antofagasta five tailing deposits have the potential to sequester between 66 to 99 Mt of CO₂. Meanwhile, thermoelectric plants in 2018 produced about 9.4 Mt of CO₂ that is available to be sequestered, with a maximum generation potential of 21.9 Mt of CO_2eq per year. The methodology and the study presented can be considered as a preliminary study to identify tailings that require further analysis. Full article

(This article belongs to the Special Issue Cleaner Production in Mineral Processing)

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14 pages, 2991 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Theoretical Study on Thermal Release of Helium-3 in Lunar Ilmenite

by Hongqing Song, Jie Zhang, Yueqiang Sun, Yongping Li, Xianguo Zhang, Dongyu Ma and Jue Kou

Minerals 2021, 11(3), 319; https://doi.org/10.3390/min11030319 - 19 Mar 2021

Cited by 5 | Viewed by 3581

Abstract

The in-situ utilization of lunar helium-3 resource is crucial to manned lunar landings and lunar base construction. Ilmenite was selected as the representative mineral which preserves most of the helium-3 in lunar soil. The implantation of helium-3 ions into ilmenite was simulated to [...] Read more.

The in-situ utilization of lunar helium-3 resource is crucial to manned lunar landings and lunar base construction. Ilmenite was selected as the representative mineral which preserves most of the helium-3 in lunar soil. The implantation of helium-3 ions into ilmenite was simulated to figure out the concentration profile of helium-3 trapped in lunar ilmenite. Based on the obtained concentration profile, the thermal release model for molecular dynamics was established to investigate the diffusion and release of helium-3 in ilmenite. The optimal heating temperature, the diffusion coefficient, and the release rate of helium-3 were analyzed. The heating time of helium-3 in lunar ilmenite under actual lunar conditions was also studied using similitude analysis. The results show that after the implantation of helium-3 into lunar ilmenite, it is mainly trapped in vacancies and interstitials of ilmenite crystal and the corresponding concentration profile follows a Gaussian distribution. As the heating temperature rises, the cumulative amounts of released helium-3 increase rapidly at first and then tend to stabilize. The optimal heating temperature of helium-3 is about 1000 K and the corresponding cumulative release amount is about 74%. The diffusion coefficient and activation energy of helium-3 increase with the temperature. When the energy of helium-3 is higher than the binding energy of the ilmenite lattice, the helium-3 is released rapidly on the microscale. Furthermore, when the heating temperature increases, the heating time for thermal release of helium-3 under actual lunar conditions decreases. For the optimal heating temperature of 1000 K, the thermal release time of helium-3 is about 1 s. The research could provide a theoretical basis for in-situ helium-3 resources utilization on the moon. Full article

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

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18 pages, 2081 KiB

Open AccessReview

A Review on the Beneficiation Methods of Borate Minerals

by Soehoe-Panhyonon Benedict Powoe, Varney Kromah, Mohammad Jafari and Saeed Chehreh Chelgani

Minerals 2021, 11(3), 318; https://doi.org/10.3390/min11030318 - 19 Mar 2021

Cited by 6 | Viewed by 3305

Abstract

The modern boron applications have adsorbed the mineral processors’ attention to improve typical boron mineral’s (BM) beneficiation methods. In this regard, dry treatment and pretreatment processes—such as magnetic separation and calcination as environmentally friendly methods, due to their minimal or zero adverse effect [...] Read more.

The modern boron applications have adsorbed the mineral processors’ attention to improve typical boron mineral’s (BM) beneficiation methods. In this regard, dry treatment and pretreatment processes—such as magnetic separation and calcination as environmentally friendly methods, due to their minimal or zero adverse effect on the environment—need more consideration. Over the years, anionic flotation has become the main technique for beneficiation of friable BMs; however, there is a gap in the investigation of cationic flotation separation since BMs’ surface negatively charges in a wide pH range. At present, enriching BMs’ flotation via surface modification is taking center stage, which can also be considered for reprocessing long-forgotten BM tailings. As a comprehensive review, this work is going to provide a synopsis of the processes, techniques, optimum parameters, and conditions—such as size reduction, zeta potential, pH, and reagents—which have been employed in the processing of BMs. Gaps in our understanding of BM’s flotation are presented in the context of addressing the existing processes, considering possibilities and rooms for efficiency improvement. Considering these gaps may improve the performance of existing methods for processing fine and ultrafine BMs, and help in the development of new technologies to improve flotation recoveries. Full article

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

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13 pages, 2173 KiB

Open AccessArticle

The Effects of Milling and pH on Co, Ni, Zn and Cu Bioleaching from Polymetallic Sulfide Concentrate

by Jarno Mäkinen, Tiina Heikola, Marja Salo and Päivi Kinnunen

Minerals 2021, 11(3), 317; https://doi.org/10.3390/min11030317 - 18 Mar 2021

Cited by 17 | Viewed by 2721

Abstract

Acid bioleaching of a low-grade and polymetallic sulfide concentrate was studied, in order to determine suitable feed material particle size and pH for efficient leaching of valuable metals. The sulfide concentrate consisted of pyrite (50 wt %), pyrrhotite (31 wt %), quartz (10 [...] Read more.

Acid bioleaching of a low-grade and polymetallic sulfide concentrate was studied, in order to determine suitable feed material particle size and pH for efficient leaching of valuable metals. The sulfide concentrate consisted of pyrite (50 wt %), pyrrhotite (31 wt %), quartz (10 wt %) and lower amounts of cobalt, nickel, zinc and copper (each <1 wt %). After adaptation of microorganisms in shake flasks, stirred tank tests were conducted at different pH levels and supplementing feed material at different particle sizes (milled to d80 < 150 µm, <50 µm, <28 µm, <19 µm). The operation at pH 1.8 was seen prone to iron precipitation, while this was not observed at a pH between 1.3 and 1.5. Additional milling to decrease particle size from the initial d80 < 150 µm had a major positive effect on cobalt- and nickel-leaching yields, proposing that at least d80 < 28 µm should be targeted. The best leaching yields for the main economic elements, cobalt and nickel, were 98% and 94%, respectively, reached with d80 < 19 µm at pH 1.3. However, it was considered that at pH 1.5, similar results could be obtained. This research sets the basis for continuing the experiments at a continuous pilot scale. Full article

(This article belongs to the Special Issue Bioprocessing of Mine and Metallurgical Wastes)

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21 pages, 13257 KiB

Open AccessArticle

Reduction of Vanadium(V) by Iron(II)-Bearing Minerals

by Edward J. O’Loughlin, Maxim I. Boyanov and Kenneth M. Kemner

Minerals 2021, 11(3), 316; https://doi.org/10.3390/min11030316 - 18 Mar 2021

Cited by 23 | Viewed by 3838

Abstract

Fe(II)-bearing minerals (magnetite, siderite, green rust, etc.) are common products of microbial Fe(III) reduction, and they provide a reservoir of reducing capacity in many subsurface environments that may contribute to the reduction of redox active elements such as vanadium; which can exist as [...] Read more.

Fe(II)-bearing minerals (magnetite, siderite, green rust, etc.) are common products of microbial Fe(III) reduction, and they provide a reservoir of reducing capacity in many subsurface environments that may contribute to the reduction of redox active elements such as vanadium; which can exist as V(V), V(IV), and V(III) under conditions typical of near-surface aquatic and terrestrial environments. To better understand the redox behavior of V under ferrugenic/sulfidogenic conditions, we examined the interactions of V(V) (1 mM) in aqueous suspensions containing 50 mM Fe(II) as magnetite, siderite, vivianite, green rust, or mackinawite, using X-ray absorption spectroscopy at the V K-edge to determine the valence state of V. Two additional systems of increased complexity were also examined, containing either 60 mM Fe(II) as biogenic green rust (BioGR) or 40 mM Fe(II) as a mixture of biogenic siderite, mackinawite, and magnetite (BioSMM). Within 48 h, total solution-phase V concentrations decreased to <20 µM in all but the vivianite and the biogenic BiSMM systems; however, >99.5% of V was removed from solution in the BioSMM and vivianite systems within 7 and 20 months, respectively. The most rapid reduction was observed in the mackinawite system, where V(V) was reduced to V(III) within 48 h. Complete reduction of V(V) to V(III) occurred within 4 months in the green rust system, 7 months in the siderite system, and 20 months in the BioGR system. Vanadium(V) was only partially reduced in the magnetite, vivianite, and BioSMM systems, where within 7 months the average V valence state stabilized at 3.7, 3.7, and 3.4, respectively. The reduction of V(V) in soils and sediments has been largely attributed to microbial activity, presumably involving direct enzymatic reduction of V(V); however the reduction of V(V) by Fe(II)-bearing minerals suggests that abiotic or coupled biotic–abiotic processes may also play a critical role in V redox chemistry, and thus need to be considered in modeling the global biogeochemical cycling of V. Full article

(This article belongs to the Special Issue Redox Reactivity of Iron Minerals in the Geosphere)

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22 pages, 3809 KiB

Open AccessEditor’s ChoiceArticle

Strength Characteristics of Clay–Rubber Waste Mixtures in Low-Frequency Cyclic Triaxial Tests

by Małgorzata Jastrzębska and Krzysztof Tokarz

Minerals 2021, 11(3), 315; https://doi.org/10.3390/min11030315 - 18 Mar 2021

Cited by 14 | Viewed by 2936

Abstract

This paper presents the results of consolidated and undrained (CU) triaxial cyclic tests related to the influence of tire waste addition on the strength characteristics of two different soils from Southern Poland: unswelling kaolin and swelling red clay. The test procedure included the [...] Read more.

This paper presents the results of consolidated and undrained (CU) triaxial cyclic tests related to the influence of tire waste addition on the strength characteristics of two different soils from Southern Poland: unswelling kaolin and swelling red clay. The test procedure included the normally consolidated remolded specimens prepared from pure red clay (RC) and kaolin (K) and their mixtures with two different fractions of shredded rubber powder (P) and granulate (G) in 5%, 10%, and 25% mass proportions. All samples were subjected to low-frequency cyclic loading carried out with a constant stress amplitude. Analysis of the results includes consideration of the effect of rubber additive and number of load cycles on the development of excess pore pressure and axial strain during the cyclic load operation and on the maximum stress deviator value. A general decrease in the shear strength due to the cyclic load operation was observed, and various effects of shear strength depended on the mixture content and size of the rubber waste particles. In general, the use of soil–rubber mixtures, especially for expansive soils and powder, should be treated with caution for cyclic loading. Full article

(This article belongs to the Special Issue Stabilisation and Reinforcement of Clays with Environmentally Friendly Materials)

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13 pages, 2787 KiB

Open AccessArticle

Modulated Monoclinic Hydroxyapatite: The Effect of pH in the Microwave Assisted Method

by Daniel Sánchez-Campos, Maria Isabel Reyes Valderrama, Susana López-Ortíz, Daniela Salado-Leza, María Eufemia Fernández-García, Demetrio Mendoza-Anaya, Eleazar Salinas-Rodríguez and Ventura Rodríguez-Lugo

Minerals 2021, 11(3), 314; https://doi.org/10.3390/min11030314 - 17 Mar 2021

Cited by 13 | Viewed by 2855

Abstract

Hydroxyapatite (HAp) is a natural hard tissue constituent widely used for bone and tooth replacement engineering. In the present work, synthetic HAp was obtained from calcium nitrate tetrahydrate (Ca(NO₃)₂·4H₂O) and ammonium phosphate dibasic (NH₄)₂ [...] Read more.

Hydroxyapatite (HAp) is a natural hard tissue constituent widely used for bone and tooth replacement engineering. In the present work, synthetic HAp was obtained from calcium nitrate tetrahydrate (Ca(NO₃)₂·4H₂O) and ammonium phosphate dibasic (NH₄)₂HPO₄ following an optimized microwave assisted hydrothermal method. The effect of pH was evaluated by the addition of ammonium hydroxide (NH₄OH). Hence, different characterization techniques were used to determine its influence on the resulted HAp powders’ size, shape, and crystallinity. By Transmission Electron Microscopy (TEM), it was observed that the reaction pH environment modifies the morphology of HAp, and a shape evolution, from sub-hedral particles at pH = 7 to rod-like nanosized HAp at pH = 10, was confirmed. Using the X-ray Diffraction (XRD) technique, the characteristic diffraction peaks of the monoclinic phase were identified. Even if the performed Rietveld analysis indicated the presence of both phases (hexagonal and monoclinic), monoclinic HAp prevails in 95% with an average crystallite size of about 23 nm. The infrared spectra (FTIR) showed absorption bands at 3468 cm⁻¹ and 630 cm⁻¹ associated with OH⁻ of hydroxyapatite, and bands at 584 cm⁻¹, 960 cm⁻¹, and 1090 cm⁻¹ that correspond to the PO₄³⁻ and CO₃²⁻ characteristic groups. In summary, this work contributes to obtaining nanosized rod-like monoclinic HAp by a simple and soft method that has not been previously reported. Full article

(This article belongs to the Special Issue Interactions of Polymers with Minerals Surfaces)

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16 pages, 5599 KiB

Open AccessArticle

Characterization of Waste Sludge Pigment from Production of ZnCl₂

by Hana Ovčačíková, Marek Velička, Petra Maierová, Jozef Vlček, Jonáš Tokarský and Tomáš Čegan

Minerals 2021, 11(3), 313; https://doi.org/10.3390/min11030313 - 17 Mar 2021

Cited by 3 | Viewed by 2348

Abstract

This study is focused on the treatment of waste sludge from a zinc chloride production in order to prepare iron-rich pigments usable for a production of glazes. In galvanizing plants, yellow waste sludge containing significant amount of ZnO, Cl, and Fe₂O [...] Read more.

This study is focused on the treatment of waste sludge from a zinc chloride production in order to prepare iron-rich pigments usable for a production of glazes. In galvanizing plants, yellow waste sludge containing significant amount of ZnO, Cl, and Fe₂O₃, is formed. This raw waste sludge cannot be used as a pigment in glaze. Therefore, three methods of treating this material were proposed: (a) washing with H₂O, (b) calcination at 180 °C and washing by H₂O, and (c) calcination at 900 °C and washing by H₂O. These methods helped to reduce Zn and Cl content up to 97%. According to X-ray fluorescence analysis percentage of Fe₂O₃ increased from ~41% to ~98%. X-ray power diffraction analysis confirmed the formation of α-Fe₂O₃ (hematite) in the pigment prepared. Scanning electron microscopy with Energy dispersive X-ray analysis showed clusters of rounded particles, and also the change in size of particles after calcination was observed. Particle size, specific surface area, and density measurements together with thermogravimetric and differential thermal analyses were performed. Pigments prepared from the waste sludge were added to transparent glaze in amounts of 1, 5, 10, and 15 wt.%. Pigment-containing glazes were applied by spraying on fired ceramic tiles and then fired at 1060 °C. Color of glazes was determined by (Commission Internationale de l’Eclairage) CIE L*a*b* coordinates as colorless, light brown shades, brown-red, brown-yellow, and deep red-brown. Comparison with colors of glazes prepared using commercial pigments was also performed. Waste sludge can be used to prepare pigments and glazes containing pigments as an alternative to commercial products. Full article

(This article belongs to the Special Issue Spectral Behavior of Mineral Pigments)

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21 pages, 6647 KiB

Open AccessArticle

Integrated Laser-Induced Breakdown Spectroscopy (LIBS) and Multivariate Wavelet Tessellation: A New, Rapid Approach for Lithogeochemical Analysis and Interpretation

by Fernando F. Fontana, Steven Tassios, Jessica Stromberg, Caroline Tiddy, Ben van der Hoek and Yulia A. Uvarova

Minerals 2021, 11(3), 312; https://doi.org/10.3390/min11030312 - 17 Mar 2021

Cited by 4 | Viewed by 3635

Abstract

This paper demonstrates a novel approach that uses wavelet tessellation in rapid analysis of raw geochemical data produced by laser-induced breakdown spectroscopy (LIBS) to produce pseudologs that are representative of stratigraphy. Single-line LIBS spectral data for seven major rock-forming elements (Al, Ca, Fe, [...] Read more.

This paper demonstrates a novel approach that uses wavelet tessellation in rapid analysis of raw geochemical data produced by laser-induced breakdown spectroscopy (LIBS) to produce pseudologs that are representative of stratigraphy. Single-line LIBS spectral data for seven major rock-forming elements (Al, Ca, Fe, Mg, Si, Na and K) were collected from a synthetic 22-sample rock-block comprising two distinct lithological groups based on mineralogy, chemistry and texture: plutonic rocks and marble. Seven sublithologies are identified within the rock-block from traditional laboratory whole-rock geochemical analysis: marble, Mg-marble, granite, quartz monzonite, foidolite, granodiorite and gabbroic diorite. Two-domain clustering (k = 2) on raw spectral LIBS data combined with wavelet tessellation was applied to generate a simplified lithological stratigraphy of marble and plutonic rocks and generate a pseudolog identical to the rock-block stratigraphy. A pseudolog generated from seven-domain clustering (k = 7) and wavelet tessellation successfully discriminated most sublithologies within the rock-block slabs, especially marble slabs. Small-scale units were identified within the more mineralogically and geochemically complex plutonic slabs. The spatial resolution of the LIBS analysis, with a measurement spacing of ~0.35 mm, allowed for assessment of individual mineral compositions and rock textures, and small-scale units within the plutonic rocks can be correlated to specific coarse-grained minerals or mineralogical associations. The application of the wavelet tessellation method to raw LIBS geochemical data offers the possibility of rapid and objective lithogeochemical analysis and interpretations which can predate further analysis (quantitative) and supplement geological logging. Full article

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21 pages, 5529 KiB

Open AccessArticle

Structural Economic Assessment of Polymetallic Nodules Mining Project with Updates to Present Market Conditions

by Tomasz Abramowski, Marcin Urbanek and Peter Baláž

Minerals 2021, 11(3), 311; https://doi.org/10.3390/min11030311 - 17 Mar 2021

Cited by 11 | Viewed by 4019

Abstract

This paper presents the economic structure, assumptions, and relations of deep-sea mining project assessment and the results of its evaluation, based on exploration activities and research in the field of geology, mining technology, processing technology, and environmental and legislative studies. The Interoceanmetal Joint [...] Read more.

This paper presents the economic structure, assumptions, and relations of deep-sea mining project assessment and the results of its evaluation, based on exploration activities and research in the field of geology, mining technology, processing technology, and environmental and legislative studies. The Interoceanmetal Joint Organization (IOM) and cooperating organizations conducted a study incorporating those elements of the project that are recognized as most important for commercial viability. On the basis of formulated financial flow of operating and capital expenses of one processing technology the possible market unit price of polymetallic nodules was estimated and the result is presented in this paper. The rapidly changing economic situation, affected inter alia by the COVID-19 pandemic, is reflected in the study and updated results are based on recent changes in metal prices. Although assumptions related to mining costs need to be confirmed during pilot mining tests, promising results have been shown in the case of the use of high-pressure acid leaching processing technology (HPAL) as well as in the case of raw ore sales. A pre-feasibility study of the project will focus on the two most promising variants of the model. Full article

(This article belongs to the Special Issue Exploration of Polymetallic Nodules)

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15 pages, 1837 KiB

Open AccessArticle

Combined Mining and Pulp-Lifting of Ferromanganese Nodules and Rare-Earth Element-Rich Mud around Minamitorishima Island in the Western North Pacific: A Prefeasibility Study

by Tetsuo Yamazaki, Naoki Nakatani, Rei Arai, Tsunehiro Sekimoto and Hiroyuki Katayama

Minerals 2021, 11(3), 310; https://doi.org/10.3390/min11030310 - 17 Mar 2021

Cited by 7 | Viewed by 2443

Abstract

An examination of the technical and economic feasibility of the combined mining of the rare-earth element-rich mud (REE-rich mud) and ferromanganese nodules (FN) around Minamitorishima (Marcus) Island in Northwest Pacific is introduced. A previous study showed that the mining of REE-rich mud around [...] Read more.

An examination of the technical and economic feasibility of the combined mining of the rare-earth element-rich mud (REE-rich mud) and ferromanganese nodules (FN) around Minamitorishima (Marcus) Island in Northwest Pacific is introduced. A previous study showed that the mining of REE-rich mud around Minamitorishima Island was not economically feasible. Therefore, in this study, three changes from the previous mining model to improve its economy are proposed. The first one is combined mining with FN in the area. The second one is introducing a pulp-lifting system that can lift both REE-rich mud and FN at high concentrations through a riser pipe. The third one is the reuse of waste mud and processed slag for construction materials. The economic evaluation results show a change from a slightly negative to quite positive economy depending on the mixing ratio of REE-rich mud and FN in the pulp-lifting. In addition, some technical approaches necessary to realize the combined mining method are introduced. Full article

(This article belongs to the Special Issue Deep-Sea Ferromanganese Nodules and Related Mineral Resources: Genesis, Exploration, and Mining)

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10 pages, 2355 KiB

Open AccessArticle

Adsorption Properties of Waste Building Sludge for Environmental Protection

by Barbora Doušová, Eva Bedrnová, Pavel Reiterman, Martin Keppert, David Koloušek, Miloslav Lhotka and Libor Mastný

Minerals 2021, 11(3), 309; https://doi.org/10.3390/min11030309 - 17 Mar 2021

Cited by 4 | Viewed by 1835

Abstract

Waste building sludge (WBS) originating in the production of concrete prestressed poles (CSW) and technical stone (TSW) used in original and Fe-modified forms (CSW_Fe, TSW_Fe) was tested as an environmentally friendly and cheap sorbent of selected cations (Cd²⁺ [...] Read more.

Waste building sludge (WBS) originating in the production of concrete prestressed poles (CSW) and technical stone (TSW) used in original and Fe-modified forms (CSW_Fe, TSW_Fe) was tested as an environmentally friendly and cheap sorbent of selected cations (Cd²⁺, Pb²⁺, Cs⁺) and anions (AsO₄³⁻, PO₄³⁻, CrO₄²⁻) from water. The experiments were performed with 0.1 and 0.5 mmol·L⁻¹ model solutions in a batch manner at laboratory temperature. Adsorption data were fitted with the Langmuir model. The adsorption of cations (Pb²⁺ and Cd²⁺) ran almost quantitatively (>97%) on both CSW and TSW. Cesium (Cs⁺) adsorption on TSW reached 80%, while in the case of CSW, it was ineffective. The modification of CSW and TSW with Fe^II (CSW_Fe and TSW_Fe) improved their adsorption selectivity to anions by up to 70%. The adsorption of PO₄³⁻ and AsO₄³⁻ ran quantitatively (>98%) on modified CSW_Fe and TSW_Fe and also on initial CSW, while CrO₄²⁻ was effectively adsorbed (≈80%) on TSW_Fe only. The adsorption affinity of tested ions in terms of adsorption capacity and sorbent consumption declined in order as follows: Pb²⁺ ≈ Cd²⁺ >> Cs⁺ for cations and AsO₄³⁻ ≈ PO₄³⁻ > CrO₄²⁻ for anions. Full article

(This article belongs to the Special Issue Designing Minerals for Remediation of Environmental Contaminants)

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3 pages, 163 KiB

Open AccessEditorial

Editorial for Special Issue “Ore Genesis and Metamorphism: Geochemistry, Mineralogy, and Isotopes”

by Pavel A. Serov

Minerals 2021, 11(3), 308; https://doi.org/10.3390/min11030308 - 17 Mar 2021

Viewed by 1534

Abstract

Magmatism, ore genesis and metamorphism are commonly associated processes that define fundamental features of the Earth’s crustal evolution from the earliest Precambrian to Phanerozoic [...] Full article

(This article belongs to the Special Issue Ore Genesis and Metamorphism: Geochemistry, Mineralogy, and Isotopes)

16 pages, 10422 KiB

Open AccessArticle

High Concentration Fine Particle Separation Performance in Hydrocyclones

by Yuekan Zhang, Meng Yang, Lanyue Jiang, Hui Wang, Jinguang Xu and Junru Yang

Minerals 2021, 11(3), 307; https://doi.org/10.3390/min11030307 - 16 Mar 2021

Cited by 12 | Viewed by 3667

Abstract

The vast majority of current research on hydrocyclone field centrifugal separation focuses on low concentration fluids having volume fraction less than 3%. For high-concentration fluids having volume fractions greater than 10%, which are often encountered in engineering, the law governing particle motion and [...] Read more.

The vast majority of current research on hydrocyclone field centrifugal separation focuses on low concentration fluids having volume fraction less than 3%. For high-concentration fluids having volume fractions greater than 10%, which are often encountered in engineering, the law governing particle motion and the classification mechanism are still unclear. In order to gain insights into the interaction between fine particles in the high concentration hydrocyclone field and to improve the hydrocyclone separation performance of these particles, a Dense Discrete Phase Model (DDPM) of the Euler-Eulerian method under the Ansys Fluent 14.5 software was employed. Numerical simulations were carried out to study the characteristics of the hydrocyclone field of dense particles and the influence of parameters, such as the diameter of the overflow outlet, diameter of the underflow outlet, and material concentration, on separation performance. The trajectories and separation efficiencies of two kinds of fine particles with different densities and six different particle sizes at high concentration were obtained. The results show that for the hydrocyclone classification of high-concentration fine particles, particles with large density and small particle size are more likely to enter the internal cyclone and discharge from the overflow. Particles with small density and large particle size are more likely to enter the external cyclone and discharge from the underflow. The research results of this topic could provide a feasible reference and theoretical basis for the centrifugal separation of high-concentration fine particle fluid. Full article

(This article belongs to the Special Issue Gravity Concentration)

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19 pages, 14029 KiB

Open AccessFeature PaperArticle

Grain-Based DEM for Particle Bed Comminution

by Michael Klichowicz and Holger Lieberwirth

Minerals 2021, 11(3), 306; https://doi.org/10.3390/min11030306 - 16 Mar 2021

Cited by 1 | Viewed by 2810

Abstract

The comminution at the grain size level for liberating the valuable minerals usually requires the highest size-specific energy. Therefore, a full understanding of the comminution process at this level is essential. Models based on the Discrete Element Method (DEM) can become a helpful [...] Read more.

The comminution at the grain size level for liberating the valuable minerals usually requires the highest size-specific energy. Therefore, a full understanding of the comminution process at this level is essential. Models based on the Discrete Element Method (DEM) can become a helpful tool for this purpose. One major concern, however, is the missing representativeness of mineral microstructures in the simulations. In this study, a method to overcome this limitation is presented. The authors show how a realistic microstructure can be implemented into a particle bed comminution simulation using grain-based models in DEM (GBM-DEM). The improved algorithm-based modeling approach is exemplarily compared to an equivalent real experiment. The simulated results obtained within the presented study show that it is possible to reproduce the interfacial breakage observed in real experiments at the grain size level. This is of particular interest as the aim of comminution in mineral processing is not only the size reduction of coarse particles, but often an efficient liberation of valuable components. Simulations with automatically generated real mineral microstructures will help to further improve the efficiency of ore processing. Full article

(This article belongs to the Special Issue Simulation Using the Discrete Element Method (DEM) in the Minerals Industry)

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15 pages, 8853 KiB

Open AccessArticle

Effect of Ferric Ions on Sulfidization Flotation of Oxidize Digenite Fine Particles and Their Significance

by Jiwei Xue, Dawei Ren, Sen Wang, Xianzhong Bu, Zhenguo Song, Chen Zhao and Tong Chen

Minerals 2021, 11(3), 305; https://doi.org/10.3390/min11030305 - 16 Mar 2021

Cited by 3 | Viewed by 1589

Abstract

Digenite fine particles are easily oxidized and ferric ions (Fe³⁺) commonly exist in the flotation pulp of digenite. This study investigated the effect of Fe³⁺ on the sulfidization flotation of oxidized digenite fine particles using sodium butyl xanthate (SBX) as [...] Read more.

Digenite fine particles are easily oxidized and ferric ions (Fe³⁺) commonly exist in the flotation pulp of digenite. This study investigated the effect of Fe³⁺ on the sulfidization flotation of oxidized digenite fine particles using sodium butyl xanthate (SBX) as a collector. The results of microflotation experiments show that the flotation rate and recovery of oxidized digenite fine particles can be improved by adding Na₂S and SBX, whereas the existence of large amounts of Fe³⁺ is not beneficial for the sulfidization flotation of digenite. The results of Fe³⁺ adsorption, zeta potential, and contact angle measurements indicate that Fe³⁺ can be adsorbed on the digenite surface mainly in the form of Fe(OH)₃, which hinders the adsorption of SBX and significantly reduces the surface hydrophobicity of digenite. X-ray photoelectron spectroscopy analysis further suggests that the poor surface hydrophobicity of digenite in the presence of Fe³⁺ is due to the production of large amounts of hydrophilic iron and copper oxides/hydroxides on the surface. Furthermore, optical microscopy analysis shows that these hydrophilic species effectively disperse digenite fine particles in the pulp, which eventually leads to the poor floatability of digenite. Therefore, it is necessary to reduce the amount of Fe³⁺ present in the pulp and adsorbed on digenite surface before sulfidization to realize effective separation of oxidized digenite fine particles and iron sulfide minerals. Full article

(This article belongs to the Special Issue Flotation Chemistry, Volume II)

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Minerals, Volume 11, Issue 3 (March 2021) – 105 articles

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