Minerals

16 pages, 7444 KiB

Open AccessArticle

Estimation of Mining-Induced Horizontal Strain Tensor of Land Surface Applying InSAR

by Wojciech T. Witkowski, Magdalena Łukosz, Artur Guzy and Ryszard Hejmanowski

Minerals 2021, 11(7), 788; https://doi.org/10.3390/min11070788 - 20 Jul 2021

Cited by 13 | Viewed by 3373 | Correction

Horizontal strains related to mining-induced subsidence may endanger infrastructure and surface users’ safety. While directional horizontal strains should be well determined, appropriate solutions for a complete assessment of the terrain surface deformation field are still required. As a result, the presented study examined [...] Read more.

Horizontal strains related to mining-induced subsidence may endanger infrastructure and surface users’ safety. While directional horizontal strains should be well determined, appropriate solutions for a complete assessment of the terrain surface deformation field are still required. As a result, the presented study examined a new method for calculating horizontal strain tensor based on the decomposition of satellite radar interferometry (InSAR) observations into vertical and azimuth look direction (ALD) displacements. Based on a geometric integral model, we tested our method on experimental data before applying it to an underground copper ore mine in Poland. In the case study, the displacement field was determined using the Multi-Temporal InSAR method on Sentinel-1 data. The model data relative error did not exceed 0.02 at σ = ±0.003. For the case study, land subsidence of up to −167 mm and ALD displacements ranging from −110 mm to +62 mm was obtained, whereas the extreme values of horizontal strains ranged from −0.52 mm/m to +0.36 mm/m at σ = ±0.050 mm/m. Our results demonstrate the high accuracy of the method in determining the horizontal strain tensor. As a result, the approach can broaden the assessment of the environmental impact of land subsidence worldwide. Full article

(This article belongs to the Special Issue Exploring Mining Landscapes: Reconciling Past and Present of Mining Activity)

► Show Figures

Figure 1

21 pages, 15549 KiB

Open AccessArticle

Geochemistry and Geochronology of Early Paleozoic Intrusive Rocks in the Terra Nova Bay Area, Northern Victoria Land, Antarctica

by Daeyeong Kim, Sang-Bong Yi, Hyeoncheol Kim, Taehwan Kim, Taehoon Kim and Jong Ik Lee

Minerals 2021, 11(7), 787; https://doi.org/10.3390/min11070787 - 20 Jul 2021

Cited by 2 | Viewed by 2956

Abstract

The Terra Nova Intrusive Complex (TNIC) in northern Victoria Land, Antarctica, results from widespread magmatism during the Early Paleozoic Ross Orogeny. According to field relationships, geochemistry, and geochronology data, the northern part of the TNIC comprises the Browning Intrusive Unit (BIU), which is [...] Read more.

The Terra Nova Intrusive Complex (TNIC) in northern Victoria Land, Antarctica, results from widespread magmatism during the Early Paleozoic Ross Orogeny. According to field relationships, geochemistry, and geochronology data, the northern part of the TNIC comprises the Browning Intrusive Unit (BIU), which is associated with an arc crustal melting including migmatization of the Wilson Metamorphic Complex, and the later Campbell Intrusive Unit (CIU), which is attributed to the mantle and crustal melting processes. Zircon U-Pb ages suggest Late Neoproterozoic to Early Cambrian protolith with Late Cambrian metamorphism (502 ± 15 Ma) in the WMC, Late Cambrian formation (~500 Ma) of the BIU, and Early Ordovician formation (~480–470 Ma) of the CIU. Sr-Nd isotopic characteristics of the BIU indicate predominant crustal component (εNd_(t) = −8.7 to −8.9), whereas those of the CIU reflect both mantle (εNd_(t) = 1.8 to 1.6) and crustal (εNd_(t) = −4.0 to −7.5) compositions. These results suggest that the northern TNIC magmatism occurring at ~500–470 Ma originated from partial melting of the mantle–mafic crust components and mixing with felsic crust components. By integrating the results with previous studies, the TNIC is considered to be formed by a combination of the mantle and mafic crust melting, crustal assimilation, felsic crust melting, and magma mixing during the Ross Orogeny. Full article

(This article belongs to the Special Issue Granite: The Signature Rock of the Earth’s Continental Crust)

► Show Figures

Figure 1

19 pages, 7686 KiB

Open AccessArticle

Distribution, Separation and Characterisation of Valuable Heavy Minerals from the Brahmaputra River Basin, Kurigram District, Bangladesh

by Aminur Rahman, Mark I. Pownceby, James Tardio, Graham J. Sparrow, Nawshad Haque and Fuad Hasan

Minerals 2021, 11(7), 786; https://doi.org/10.3390/min11070786 - 20 Jul 2021

Cited by 6 | Viewed by 3975

Abstract

Bangladesh’s heavy minerals deposits in river systems remain largely unexplored with past research restricted to beach placer deposits along the south-eastern coastline of the country. In this study, 64 samples were collected from stable sand bars from the northern Brahmaputra River. The average [...] Read more.

Bangladesh’s heavy minerals deposits in river systems remain largely unexplored with past research restricted to beach placer deposits along the south-eastern coastline of the country. In this study, 64 samples were collected from stable sand bars from the northern Brahmaputra River. The average total heavy minerals (THM) from all sample sites was 10.73 wt%, with the THM concentrations generally highest at the outermost edges of the river and lowest within the mid-channel regions. There was no variation in THM content from north (upstream) to south (downstream). Valuable heavy minerals (VHMs) magnetite, ilmenite, garnet and zircon made up around 25–30 wt% of the THM content, with other heavy minerals including amphibole, pyroxene, kyanite, sillimanite, monazite, apatite and xenotime making up the remaining 70–75 wt%. A VHM distribution map showed that the upstream division of the studied area appeared to be the most prospective for valuable heavy minerals. A bench scale heavy mineral sands beneficiation flowsheet involving unit processes employing gravity, magnetic and electrostatic properties was designed and based on a detailed characterisation and phase analysis of the resulting fractions, it was determined that VHMs made up ~2 wt% of the material recovered. Of these, garnet and ilmenite made up the bulk of the VHMs at levels of 0.88 and 0.51 wt%, respectively, with recoveries of >83%. Characterisation of the concentrates showed that further refinement of the processing conditions is required to generate concentrates that are potentially suitable for commercial applications. Full article

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

► Show Figures

Figure 1

19 pages, 4874 KiB

Open AccessArticle

Phosphorus-Rich Ash from Poultry Manure Combustion in a Fluidized Bed Reactor

by Zdzisław Adamczyk, Magdalena Cempa and Barbara Białecka

Minerals 2021, 11(7), 785; https://doi.org/10.3390/min11070785 - 20 Jul 2021

Cited by 11 | Viewed by 2858

Abstract

The aim of this study was to examine the physico-chemical and phase characteristics of ash obtained in the process of the combustion of Polish poultry manure in a laboratory reactor with a bubbling fluidized bed. Three experiments, differing in the grain size and [...] Read more.

The aim of this study was to examine the physico-chemical and phase characteristics of ash obtained in the process of the combustion of Polish poultry manure in a laboratory reactor with a bubbling fluidized bed. Three experiments, differing in the grain size and morphology of the raw material, the method of its dosing and the type of fluidized bed, were carried out. The contents of the main chemical components and trace elements in the obtained ash samples were determined using WDXRF, and the phase composition was examined through the XRD method. The morphology and the chemical composition of grains in a given micro-area using the SEM/EDS method were also investigated. The highest concentration of phosphorus (from 28.07% wt. to 29.71% wt. as P₂O₅ equivalent), the highest proportion of amorphous substance (from 56.7% wt. to 59.0% wt.) and the lowest content of unburned organic substance (LOI from 6.42% to 9.16%) (i.e., the best process efficiency), was obtained for the experiment in which the starting bed was quartz sand and poultry manure was fed to the reactor in the form of pellets. It has been calculated that in this case, the amorphous phase contains more than half of the phosphorus. The method of carrying out the combustion process has a significant impact on the phase composition and, consequently, on the availability of phosphorus. Full article

(This article belongs to the Special Issue Fluidized Bed Combustion (FBC) Fly Ashes—Characteristics and Use)

► Show Figures

Figure 1

25 pages, 9317 KiB

Open AccessFeature PaperArticle

Worth from Waste: Utilizing a Graphite-Rich Fraction from Spent Lithium-Ion Batteries as Alternative Reductant in Nickel Slag Cleaning

by Anna Dańczak, Ronja Ruismäki, Tommi Rinne, Lassi Klemettinen, Hugh O’Brien, Pekka Taskinen, Ari Jokilaakso and Rodrigo Serna-Guerrero

Minerals 2021, 11(7), 784; https://doi.org/10.3390/min11070784 - 19 Jul 2021

Cited by 12 | Viewed by 3537

Abstract

One possible way of recovering metals from spent lithium-ion batteries is to integrate the recycling with already existing metallurgical processes. This study continues our effort on integrating froth flotation and nickel-slag cleaning process for metal recovery from spent batteries (SBs), using anodic graphite [...] Read more.

One possible way of recovering metals from spent lithium-ion batteries is to integrate the recycling with already existing metallurgical processes. This study continues our effort on integrating froth flotation and nickel-slag cleaning process for metal recovery from spent batteries (SBs), using anodic graphite as the main reductant. The SBs used in this study was a froth fraction from flotation of industrially prepared black mass. The effect of different ratios of Ni-slag to SBs on the time-dependent phase formation and metal behavior was investigated. The possible influence of graphite and sulfur contents in the system on the metal alloy/matte formation was described. The trace element (Co, Cu, Ni, and Mn) concentrations in the slag were analyzed using the laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) technique. The distribution coefficients of cobalt and nickel between the metallic or sulfidic phase (metal alloy/matte) and the coexisting slag increased with the increasing amount of SBs in the starting mixture. However, with the increasing concentrations of graphite in the starting mixture (from 0.99 wt.% to 3.97 wt.%), the Fe concentration in both metal alloy and matte also increased (from 29 wt.% to 68 wt.% and from 7 wt.% to 49 wt.%, respectively), which may be challenging if further hydrometallurgical treatment is expected. Therefore, the composition of metal alloy/matte must be adjusted depending on the further steps for metal recovery. Full article

(This article belongs to the Special Issue Battery Minerals)

► Show Figures

Figure 1

15 pages, 4152 KiB

Open AccessArticle

The Effect of pH, Ionic Strength and the Presence of Pb^II on the Formation of Calcium Carbonate from Homogenous Alkaline Solutions at Room Temperature

by Fulvio Di Lorenzo, Kay Steiner and Sergey V. Churakov

Minerals 2021, 11(7), 783; https://doi.org/10.3390/min11070783 - 19 Jul 2021

Cited by 5 | Viewed by 3285

Abstract

Precipitation of calcium carbonates in aqueous systems is an important factor controlling various industrial, biological, and geological processes. In the first part of this study, the well-known titration approach introduced by Gebauer and coworkers in 2008 s used to obtain reliable experimental dataset [...] Read more.

Precipitation of calcium carbonates in aqueous systems is an important factor controlling various industrial, biological, and geological processes. In the first part of this study, the well-known titration approach introduced by Gebauer and coworkers in 2008 s used to obtain reliable experimental dataset for the deep understanding of CaCO₃ nucleation kinetics in supersaturated solutions over a broad range of pH and ionic strength conditions. In the second part, the effect of impurities, i.e., 1 mol% of Pb²⁺, was assessed in the same range of experimental conditions. Divalent lead has been shown to have an inhibitory effect in all ranges of the conditions tested except for pH 8 and low ionic strength (≤0.15 mol/L). Future investigations might take advantage of the methodology and the data provided in this work to investigate the effect of other system variables. The investigation of all the major variables and the assessment of eventual synergic effects could improve our ability to predict the formation of CaCO₃ in complex natural systems. Full article

(This article belongs to the Special Issue Mineral Surface Reactivity with Application to Contaminant Retention and Element Partitioning)

► Show Figures

Figure 1

16 pages, 3155 KiB

Open AccessArticle

Consistent Characterization of Color Degradation Due to Artificial Aging Procedures at Popular Pigments of Byzantine Iconography

by Stamatios Amanatiadis, Georgios Apostolidis and Georgios Karagiannis

Minerals 2021, 11(7), 782; https://doi.org/10.3390/min11070782 - 19 Jul 2021

Cited by 6 | Viewed by 3618

Abstract

The degradation effects of artificial aging on the “true” pigment color of Byzantine iconography are thoroughly investigated in this work. For this purpose, a multi-material palette is fabricated, consisting of various popular egg-tempera pigments, while the original recipes from the literature are utilized [...] Read more.

The degradation effects of artificial aging on the “true” pigment color of Byzantine iconography are thoroughly investigated in this work. For this purpose, a multi-material palette is fabricated, consisting of various popular egg-tempera pigments, while the original recipes from the literature are utilized in order to mimic the genuine art of Byzantine painters. Then, artificial aging procedures are appropriately employed to simulate environmental fluctuations in historical buildings, such as churches. A total of four time steps are investigated, including the initial condition, and pigments’ spectra in the ultraviolet/visible (UV/Vis) area are acquired in the diffuse reflectance mode at each individual step. Moreover, a color characterization procedure is realized via the quantification of lightness and saturation by means of the measured UV/Vis spectrum. The main objectives of this work are to determine the color stability, the type of color degradation, and generally the color response through time of the studied pigments. The extracted results indicate that a couple of pigments suffer severe color degradation while the majority present moderate darkening or discoloration. Full article

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

► Show Figures

Figure 1

12 pages, 4144 KiB

Open AccessArticle

Characterization and Analysis of the Mortars in the Church of the Company of Jesus—Quito (Ecuador)

by M. Lenin Lara, David Sanz-Arauz, Sol López-Andrés and Inés del Pino

Minerals 2021, 11(7), 781; https://doi.org/10.3390/min11070781 - 19 Jul 2021

Cited by 5 | Viewed by 6401

Abstract

The Church of the Company of Jesus in Quito (1605–1765) is one of the most remarkable examples of colonial religious architecture on the World Heritage List. This church has multiple constructive phases and several interventions with no clear record of the entire architectural [...] Read more.

The Church of the Company of Jesus in Quito (1605–1765) is one of the most remarkable examples of colonial religious architecture on the World Heritage List. This church has multiple constructive phases and several interventions with no clear record of the entire architectural site, including the historical mortars. A total of 14 samples of coating mortars inside the central nave were taken, with the protocols suggested by the research team and a comparative sample of the architectural group that does not have intervention. The analysis presented in this paper focuses on mineralogical characterization, semi-quantitative analysis by X-ray diffraction and scanning electron microscopy with microanalysis of the samples. The results showed the presence of volcanic aggregate lime and gypsum, used in lining mortars and joint mortars. Mineralogical and textural composition data have allowed the mortar samples to be relatively dated. Full article

(This article belongs to the Special Issue Mineralogical, Textural, and Physical Characterization of Lime Mortars)

► Show Figures

Figure 1

15 pages, 5246 KiB

Open AccessFeature PaperArticle

Nitrogen under Super-Reducing Conditions: Ti Oxynitride Melts in Xenolithic Corundum Aggregates from Mt Carmel (N. Israel)

by William L. Griffin, Sarah E. M. Gain, Martin Saunders, Olivier Alard, Jeremy Shaw, Vered Toledo and Suzanne Y. O’Reilly

Minerals 2021, 11(7), 780; https://doi.org/10.3390/min11070780 - 18 Jul 2021

Cited by 7 | Viewed by 2561

Abstract

Titanium oxynitrides (Ti(N,O,C)) are abundant in xenolithic corundum aggregates in pyroclastic ejecta of Cretaceous volcanoes on Mount Carmel, northern Israel. Petrographic observations indicate that most of these nitrides existed as melts, immiscible with coexisting silicate and Fe-Ti-C silicide melts; some nitrides may also [...] Read more.

Titanium oxynitrides (Ti(N,O,C)) are abundant in xenolithic corundum aggregates in pyroclastic ejecta of Cretaceous volcanoes on Mount Carmel, northern Israel. Petrographic observations indicate that most of these nitrides existed as melts, immiscible with coexisting silicate and Fe-Ti-C silicide melts; some nitrides may also have crystallized directly from the silicide melts. The TiN phase shows a wide range of solid solution, taking up 0–10 wt% carbon and 1.7–17 wt% oxygen; these have crystallized in the halite (fcc) structure common to synthetic and natural TiN. Nitrides coexisting with silicide melts have higher C/O than those coexisting with silicate melts. Analyses with no carbon fall along the TiN–TiO join in the Ti–N–O phase space, implying that their Ti is a mixture of Ti³⁺ and Ti²⁺, while those with 1–3 at.% C appear to be solid solutions between TiN and Ti_0.75O. Analyses with >10 at% C have higher Ti²⁺/Ti³⁺, reflecting a decrease in fO₂. Oxygen fugacity was 6 to 8 log units below the iron–wüstite buffer, at or below the Ti₂O₃–TiO buffer. These relationships and coexisting silicide phases indicate temperatures of 1400–1100 °C. Ti oxynitrides are probably locally abundant in the upper mantle, especially in the presence of CH₄–H₂ fluids derived from the deeper metal-saturated mantle. Full article

(This article belongs to the Special Issue 10th Anniversary of Minerals: Frontiers of Mineral Science)

► Show Figures

Figure 1

22 pages, 5452 KiB

Open AccessArticle

Damage Evolution of Granodiorite after Heating and Cooling Treatments

by Mohamed Elgharib Gomah, Guichen Li, Salah Bader, Mohamed Elkarmoty and Mohamed Ismael

Minerals 2021, 11(7), 779; https://doi.org/10.3390/min11070779 - 18 Jul 2021

Cited by 19 | Viewed by 3211

Abstract

The awareness of the impact of high temperatures on rock properties is essential to the design of deep geotechnical applications. The purpose of this research is to assess the influence of heating and cooling treatments on the physical and mechanical properties of Egyptian [...] Read more.

The awareness of the impact of high temperatures on rock properties is essential to the design of deep geotechnical applications. The purpose of this research is to assess the influence of heating and cooling treatments on the physical and mechanical properties of Egyptian granodiorite as a degrading factor. The samples were heated to various temperatures (200, 400, 600, and 800 °C) and then cooled at different rates, either slowly cooled in the oven and air or quickly cooled in water. The porosity, water absorption, P-wave velocity, tensile strength, failure mode, and associated microstructural alterations due to thermal effect have been studied. The study revealed that the granodiorite has a slight drop in tensile strength, up to 400 °C, for slow cooling routes and that most of the physical attributes are comparable to natural rock. Despite this, granodiorite thermal deterioration is substantially higher for quick cooling than for slow cooling. Between 400:600 °C is ‘the transitional stage’, where the physical and mechanical characteristics degraded exponentially for all cooling pathways. Independent of the cooling method, the granodiorite showed a ductile failure mode associated with reduced peak tensile strengths. Additionally, the microstructure altered from predominantly intergranular cracking to more trans-granular cracking at 600 °C. The integrity of the granodiorite structure was compromised at 800 °C, the physical parameters deteriorated, and the rock tensile strength was negligible. In this research, the temperatures of 400, 600, and 800 °C were remarked to be typical of three divergent phases of granodiorite mechanical and physical properties evolution. Furthermore, 400 °C could be considered as the threshold limit for Egyptian granodiorite physical and mechanical properties for typical thermal underground applications. Full article

► Show Figures

Figure 1

20 pages, 2749 KiB

Open AccessArticle

The Effect of Mineral-Based Mixtures Containing Coal Fly Ash and Sewage Sludge on Chlorophyll Fluorescence and Selected Morphological Parameters of Deciduous and Coniferous Trees

by Agnieszka Bęś, Łukasz Sikorski and Krzysztof Szreder

Minerals 2021, 11(7), 778; https://doi.org/10.3390/min11070778 - 18 Jul 2021

Cited by 3 | Viewed by 2789

Abstract

Coal fly ash (CFA), which is generated in huge quantities in coal-fired power plants, is a problem worldwide. Mixtures with ash and sewage sludge alter morphological and biochemical characteristics of plants. In this experiment, the response of pine, spruce, beech and alder growing [...] Read more.

Coal fly ash (CFA), which is generated in huge quantities in coal-fired power plants, is a problem worldwide. Mixtures with ash and sewage sludge alter morphological and biochemical characteristics of plants. In this experiment, the response of pine, spruce, beech and alder growing for four years to mineral mixtures based on coal fly ash and high salinity sewage sludge (SS) was studied. The four-year experiment determined the chlorophyll a fluorescence of the tested plants, their height and yield, the salinity level of the tested mixtures and their phytotoxicity. Mixtures of coal ash with sewage sludge proved to be more beneficial to plants than their separate application. After four years, among the studied species, the highest increase in height and biomass was recorded for European alder and Scots pine. These species were also characterized by high photosynthetic indices. Mixtures containing 29% SS created optimal conditions for the development of the studied tree species. Grey alder and ponderosa pine can be recommended for reclamation of degraded areas where CFA and SS mixtures are used. Full article

(This article belongs to the Special Issue Application of Mineral-Based Amendments, Volume II)

► Show Figures

Figure 1

15 pages, 6061 KiB

Open AccessArticle

Assessment of Selected Characteristics of Enrichment Products for Regular and Irregular Aggregates Beneficiation in Pulsating Jig

by Tomasz Gawenda, Daniel Saramak, Agata Stempkowska and Zdzisław Naziemiec

Minerals 2021, 11(7), 777; https://doi.org/10.3390/min11070777 - 17 Jul 2021

Cited by 5 | Viewed by 2076

Abstract

Article concerns problem of jig beneficiation of mineral aggregates and focuses especially on problem of separation of hard-enrichable materials. Investigative programme covered tests in laboratory and semi-plant scale and material with different content of regular and irregular particles, along with various particle size [...] Read more.

Article concerns problem of jig beneficiation of mineral aggregates and focuses especially on problem of separation of hard-enrichable materials. Investigative programme covered tests in laboratory and semi-plant scale and material with different content of regular and irregular particles, along with various particle size fractions, was under analysis. Two patented solutions were utilized as methodological approach and densities and absorbabilities of individual products were determined and major novelty of approach consist in separate beneficiation of regular and irregular particles. Results of laboratory investigations showed that more favorable separation effectiveness was observed for the narrow particle size fractions of feed material. In terms of absorbability difference between separation products from I and IV layer was 0.4–0.5% higher for regular particles, and up to 0.5% higher for irregular grains. Differences in densities of respective products were 0.1% higher for regular particles. Results of semi-plant tests confirmed the outcomes achieved in laboratory scale. The qualitative characteristics of separation products in terms of micro-Deval and LA comminution resistance indices were one category higher for regular particles, and two categories higher for irregular grains, comparing to the raw material. Full article

(This article belongs to the Special Issue Advanced Techniques and Efficiency Assessment of Mechanical Processing)

► Show Figures

Figure 1

13 pages, 245 KiB

Open AccessArticle

Effectiveness of Natural Language Processing Based Machine Learning in Analyzing Incident Narratives at a Mine

by Rajive Ganguli, Preston Miller and Rambabu Pothina

Minerals 2021, 11(7), 776; https://doi.org/10.3390/min11070776 - 17 Jul 2021

Cited by 13 | Viewed by 3442

Abstract

To achieve the goal of preventing serious injuries and fatalities, it is important for a mine site to analyze site specific mine safety data. The advances in natural language processing (NLP) create an opportunity to develop machine learning (ML) tools to automate analysis [...] Read more.

To achieve the goal of preventing serious injuries and fatalities, it is important for a mine site to analyze site specific mine safety data. The advances in natural language processing (NLP) create an opportunity to develop machine learning (ML) tools to automate analysis of mine health and safety management systems (HSMS) data without requiring experts at every mine site. As a demonstration, nine random forest (RF) models were developed to classify narratives from the Mine Safety and Health Administration (MSHA) database into nine accident types. MSHA accident categories are quite descriptive and are, thus, a proxy for high level understanding of the incidents. A single model developed to classify narratives into a single category was more effective than a single model that classified narratives into different categories. The developed models were then applied to narratives taken from a mine HSMS (non-MSHA), to classify them into MSHA accident categories. About two thirds of the non-MSHA narratives were automatically classified by the RF models. The automatically classified narratives were then evaluated manually. The evaluation showed an accuracy of 96% for automated classifications. The near perfect classification of non-MSHA narratives by MSHA based machine learning models demonstrates that NLP can be a powerful tool to analyze HSMS data. Full article

(This article belongs to the Special Issue Advances in Computational Intelligence Applications in the Mining Industry)

17 pages, 3596 KiB

Open AccessReview

Contamination of the Soil–Groundwater–Crop System: Environmental Risk and Opportunities

by Maria Economou-Eliopoulos and Ifigeneia Megremi

Minerals 2021, 11(7), 775; https://doi.org/10.3390/min11070775 - 16 Jul 2021

Cited by 15 | Viewed by 4156

Abstract

The increasing development of industries, resulting in a large volume of mining, smelting, and combustion wastes, and intense agricultural activities, due to demand for food and energy, have caused environmental hazards for food quality and ecosystems. This is a review on the contamination [...] Read more.

The increasing development of industries, resulting in a large volume of mining, smelting, and combustion wastes, and intense agricultural activities, due to demand for food and energy, have caused environmental hazards for food quality and ecosystems. This is a review on the contamination of the soil–groundwater–crop system and a potential reduction of the contamination by a gradual shift towards green economy within the European Union and on a worldwide scale. Available mineralogical and geochemical features from contaminated Neogene basins have shown a diversity in the contamination sources for soil and groundwater, and highlighted the need to define the contamination sources, hot spots, degree/extent of contamination, and provide ways to restrict the transfer of heavy metals/metalloids into the food chain, without the reduction of the agricultural and industrial production. Among harmful elements for human health and ecosystems, the contamination of groundwater (thousands of μg/L Cr(VI)) by industrial activities in many European countries is of particular attention. Although Cr(VI) can be reduced to Cr(III) and be completely attenuated in nature under appropriate pH and Eh conditions, the contamination by Cr(VI) of coastal groundwater affected by the intrusion of seawater often remains at the hundreds μg/L level. A positive trend between B and Cr(VI) may provide insights on the role of the borate [B(OH)₄]⁻ ions, a potential buffer, on the stability of Cr(VI) in coastal groundwater. Efforts are needed towards reducing toxic metal(loids) from the industrial wastewaters prior to their discharge into receptors, as well as the transformation of hazardous mining/industrial wastes to new products and applications to the optimization of agricultural management strategies. Full article

(This article belongs to the Special Issue Recent Contributions of Female Scientists to the Advancement of Environmental Mineralogy)

► Show Figures

Figure 1

19 pages, 4661 KiB

Open AccessArticle

Characterization of the Physical, Chemical, and Adsorption Properties of Coal-Fly-Ash–Hydroxyapatite Composites

by Eleonora Sočo, Dorota Papciak, Magdalena M. Michel, Dariusz Pająk, Andżelika Domoń and Bogdan Kupiec

Minerals 2021, 11(7), 774; https://doi.org/10.3390/min11070774 - 16 Jul 2021

Cited by 11 | Viewed by 3614

Abstract

(1) Hydroxyapatite (HAp), which can be obtained by several methods, is known to be a good adsorbent. Coal fly ash (CFA) is a commonly reused byproduct also used in environmental applications as an adsorbent. We sought to answer the following question: Can CFA [...] Read more.

(1) Hydroxyapatite (HAp), which can be obtained by several methods, is known to be a good adsorbent. Coal fly ash (CFA) is a commonly reused byproduct also used in environmental applications as an adsorbent. We sought to answer the following question: Can CFA be included in the method of HAp wet synthesis to produce a composite capable of adsorbing both heavy metals and dyes? (2) High calcium lignite CFA from the thermal power plant in Bełchatów (Poland) was used as the base to prepare CFA–HAp composites. Four types designated CFA–HAp1–4 were synthesized via the wet method of in situ precipitation. The synthesis conditions differed in terms of the calcium reactants used, pH, and temperature. We also investigated the equilibrium adsorption of Cu(II) and rhodamine B (RB) on CFA–HAp1–4. The data were fitted using the Langmuir, Freundlich, and Redlich–Peterson models and validated using R² and χ²/DoF. Surface changes in CFA–HAp2 following Cu(II) and RB adsorption were assessed using SEM, SE, and FT-IR analysis. (3) The obtained composites contained hydroxyapatite (Ca/P 1.67) and aluminosilicates. The mode of Cu(II) and RB adsorption could be explained by the Redlich–Peterson model. The CFA–HAp2 obtained using CFA, Ca(NO₃)₂, and (NH₄)₂HPO₄ at RT and pH 11 exhibited the highest maximal adsorption capacity: 73.6 mg Cu/g and 87.0 mg RB/g. (4) The clear advantage of chemisorption over physisorption was indicated by the Cu(II)–CFA–HAp system. The RB molecules present in the form of uncharged lactone were favorably adsorbed even on strongly deprotonated CFA–HAp surfaces. Full article

(This article belongs to the Special Issue Fluidized Bed Combustion (FBC) Fly Ashes—Characteristics and Use)

► Show Figures

Figure 1

32 pages, 6030 KiB

Open AccessArticle

Trace-Element Geochemistry of Sulfides in Upper Mantle Lherzolite Xenoliths from East Antarctica

by Alexandre V. Andronikov, Irina E. Andronikova and Tamara Sidorinova

Minerals 2021, 11(7), 773; https://doi.org/10.3390/min11070773 - 16 Jul 2021

Cited by 5 | Viewed by 2840

Abstract

Sulfides in upper mantle lherzolite xenoliths from Cretaceous alkaline-ultramafic rocks in the Jetty Peninsula (East Antarctica) were studied for their major and trace-element compositions using SEM and LA-ICP-MS applied in situ. Modal abundance of sulfides is the lowest in Cpx-poor lherzolites ≤ Spl-Grt [...] Read more.

Sulfides in upper mantle lherzolite xenoliths from Cretaceous alkaline-ultramafic rocks in the Jetty Peninsula (East Antarctica) were studied for their major and trace-element compositions using SEM and LA-ICP-MS applied in situ. Modal abundance of sulfides is the lowest in Cpx-poor lherzolites ≤ Spl-Grt lherzolites << Cpx-rich lherzolites. Most sulfides are either interstitial (i-type) or inclusions in rock-forming minerals (e-type) with minor sulfide phases mostly present in metasomatic veinlets and carbonate-silicate interstitial patches (m-type). The main sulfide assemblage is pentlandite + chalcopyrite ± pyrrhotite; minor sulfides are polydymite, millerite, violarite, siegenite, and monosulfide solution (mss). Sulfide assemblages in the xenolith matrix are a product of the subsolidus re-equilibration of primary mss at temperatures below ≤300 °C. Platinum group elements (PGE) abundances suggest that most e-type sulfides are the residues of melting processes and that the i-type sulfides are crystallization products of sulfide-bearing fluids/liquids. The m-type sulfides might have resulted from low-temperature metasomatism by percolating sulfide-carbonate-silicate fluids/melts. The PGE in sulfide record processes are related to partial melting in mantle and intramantle melt migration. Most other trace elements initially partitioned into interstitial sulfide liquid and later metasomatically re-enriched residual sulfides overprinting their primary signatures. The extent of element partitioning into sulfide liquids depends on P, T, fO₂, and host peridotite composition. Full article

(This article belongs to the Special Issue 10th Anniversary of Minerals: Frontiers of Mineral Science)

► Show Figures

Figure 1

22 pages, 4601 KiB

Open AccessArticle

Chromite Mineralization in the Sopcheozero Deposit (Monchegorsk Layered Intrusion, Fennoscandian Shield)

by Artem V. Mokrushin and Valery F. Smol’kin

Minerals 2021, 11(7), 772; https://doi.org/10.3390/min11070772 - 16 Jul 2021

Cited by 8 | Viewed by 3070

Abstract

In 1990, the Sopcheozero Cr deposit was discovered in the Monchegorsk Paleoproterozoic layered mafic-ultramafic layered intrusion (Monchepluton). This stratiform early-magmatic deposit occurs in the middle part of the Dunite Block, which is a member of the Monchepluton layered series. The Cr₂O [...] Read more.

In 1990, the Sopcheozero Cr deposit was discovered in the Monchegorsk Paleoproterozoic layered mafic-ultramafic layered intrusion (Monchepluton). This stratiform early-magmatic deposit occurs in the middle part of the Dunite Block, which is a member of the Monchepluton layered series. The Cr₂O₃ average-weighted content in ordinary and rich ores of the deposit is 16.65 and 38.76 wt.%, respectively, at gradually changing concentrations within the rich, ordinary and poor ore types and ore body in general. The ores of the Sopcheozero deposit, having a ratio of Cr₂O₃/FeO_total = 0.9–1.7, can serve as raw materials for the refractory and chemical industries. The ore Cr-spinel (magnochromite and magnoalumochromite) is associated with highly magnesian olivine (96–98 Fo) rich in Ni (0.4–1.1 wt.%). It confirms a low S content in the melt and complies with the low oxygen fugacity. The coexisting Cr-spinel-olivine pairs crystallized at temperatures from 1258 to 1163 °C, with accessory Cr-spinel crystallizing at relatively low, while ore Cr-spinel at higher temperatures. The host rock and ore distinguish with widespread plastic deformations of olivine at the postcrystallization phase under conditions of high temperature (above 400 °C) and pressure (5 kbar). At the post magmatic Svecofennian stage (1.84 Ga), the deposit, jointly with the Monchepluton, was subject to diverse tectonic deformations. Full article

(This article belongs to the Special Issue Chromite Deposits: Mineralogy, Petrology and Genesis)

► Show Figures

Figure 1

15 pages, 15169 KiB

Open AccessArticle

Revealing Artists’ Collaboration in a 14th Century Manuscript by Non-Invasive Analyses

by Michela Perino, Lucilla Pronti, Lucrezia Gaia Di Forti, Martina Romani, Cecilia Taverna, Lola Massolo, Francesca Manzari, Mariangela Cestelli-Guidi, Alessandro Nucara and Anna Candida Felici

Minerals 2021, 11(7), 771; https://doi.org/10.3390/min11070771 - 16 Jul 2021

Cited by 10 | Viewed by 3328

Abstract

In the last decades, the working methods of late medieval illuminators have been widely discussed by art historians and codicologists. Non-invasive analyses are able to characterise the painting methods of illuminators as well as investigate artistic collaborations among them. The aim of this [...] Read more.

In the last decades, the working methods of late medieval illuminators have been widely discussed by art historians and codicologists. Non-invasive analyses are able to characterise the painting methods of illuminators as well as investigate artistic collaborations among them. The aim of this study was to characterise the painting palettes and techniques of different artists who illuminated two leaves from an early fourteenth century manuscript. The analyses were carried out with non-invasive and portable techniques such as Energy Dispersive X-ray Fluorescence (ED-XRF) spectrometry, Fiber Optics Reflectance Spectroscopy (FORS) and Raman spectroscopy. The paper highlights the differences among three rich and varied palettes and examines the pigments ultramarine, azurite, verdigris, earths, orpiment, red lead, vermillion, lead white, yellow lake, indigo, brazilwood and lac, used independently or in mixtures. We have demonstrated the effectiveness of non-invasive analyses as a tool to differentiate hands of artists who have worked on the same page. Furthermore, the comparison with analyses carried out on leaves attributed to the workshop of Pacino di Bonaguida allows to investigate in-depth the production of the main illuminators active in Florence at the dawn of the Renaissance. Full article

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

► Show Figures

Figure 1

12 pages, 2407 KiB

Open AccessArticle

Tests of Strength Parameters of Hydro-Mixtures Based on Ashes from a Fluidized Bed Boiler in the In-Situ Approach

by Marcin Popczyk

Minerals 2021, 11(7), 770; https://doi.org/10.3390/min11070770 - 16 Jul 2021

Cited by 1 | Viewed by 1492

Abstract

The paper presents the practical use of a solidifying hydro-mixture based on ashes from fluidized bed boilers under hard coal mine conditions for filling an incline connecting the headgate and tailgate of a longwall running along the strike with roof caving. The reason [...] Read more.

The paper presents the practical use of a solidifying hydro-mixture based on ashes from fluidized bed boilers under hard coal mine conditions for filling an incline connecting the headgate and tailgate of a longwall running along the strike with roof caving. The reason for filling the incline with a material of preset strength parameters was to minimize the methane hazard in the extracted coal seam. Due to a great demand for fill material, which translates into economic considerations, the option of applying fine-fraction waste material was selected. Preliminary laboratory tests of the physical and mechanical properties of hydro-mixtures based on ash obtained from a fluidized bed boiler of a power plant, allowed us to select a specific hydro-mixture meeting the requirements. After 95 days, the incline filled with the proposed hydro-mixture was subjected to exploitation along with the advance of longwall working. This enabled the in-situ collection of a number of fill material samples from various places along the entire length of the incline. Then their strength was tested and the results compared with the obtained test results of identical material seasoned under laboratory conditions. The obtained results constitute a unique research material since it is practically impossible to verify the laboratory-determined strength parameters of the solidifying fine-fraction hydro-mixtures under in-situ conditions. Thsis results mainly from the lack of technical capabilities and poor access to the places where fine-fraction hydro-mixtures are applied, mostly abandoned cavings or parts of workings separated by dams. Full article

(This article belongs to the Special Issue Fluidized Bed Combustion (FBC) Fly Ashes—Characteristics and Use)

► Show Figures

Figure 1

20 pages, 4466 KiB

Open AccessArticle

Mineral Geochemistry of Basaltic Rocks from IODP Expeditions 334 and 344: Implications for Magmatic Processes of Cocos Ridge Segment Being Subducted Beneath the Middle America Trench

by Quanshu Yan and Zhenmin Ge

Minerals 2021, 11(7), 769; https://doi.org/10.3390/min11070769 - 16 Jul 2021

Cited by 1 | Viewed by 2353

Abstract

The Cocos Ridge, which is subducted beneath the Central American Volcanic Arc, has a complex tectonic evolution history due to plume-ridge interaction between the Galápagos plume and the Cocos—Nazca spreading center. This study presents major and trace element analyses of plagioclase and clinopyroxenes [...] Read more.

The Cocos Ridge, which is subducted beneath the Central American Volcanic Arc, has a complex tectonic evolution history due to plume-ridge interaction between the Galápagos plume and the Cocos—Nazca spreading center. This study presents major and trace element analyses of plagioclase and clinopyroxenes hosted by Cocos Ridge basaltic rocks that were drilled in three holes (U1381A, U1381C and U1414A) of Sites U1381 and U1414 on the Cocos Ridge close to the Middle America Trench during the Integrated Ocean Drilling Program (IODP) Expeditions 334 and 344. The results show that (1) plagioclases are mainly bytownite and labradorite with subordinate andesine, which are enriched in light rare earth elements (LREE) and some large-ion lithophile elements (LILE) and exhibit marked positive Eu anomalies; and (2) that clinopyroxenes are augites, which are depleted in highly incompatible elements such as LREE and LILE, have nearly flat heavy rare earth elements patterns (HREE) and lack Eu anomalies in chondrite-normalized rare earth element (REE) diagrams. During the ascent to the surface, the primary magmas experienced fractional crystallization of plagioclase, clinopyroxene, Ti-Fe oxides and possibly olivine (complete replacement of olivine by secondary minerals). The crystallization temperatures of plagioclase phenocrysts and microlites are 1050 to 1269 °C, and 866 to 1038 °C, respectively, and the pressures of plagioclase phenocrysts are 0.3–0.7 GPa. The crystallization temperatures of clinopyroxene phenocrysts/micro-phenocrysts is 1174–1268 °C, similar to those of plagioclase phenocrysts, suggesting some of clinopyroxene and plagioclase phenocrysts cotectic crystallized during early stage of magmatic evolution. In addition, the equilibrium pressures of clinopyroxene phenocrysts/micro phenocrysts are 0.02–0.97 GPa, implying that the clinopyroxene started to crystallize within the mantle, and magma evolution has undergone an early crystallization stage with clinopyroxene and no plagioclase. Full article

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

► Show Figures

Figure 1

12 pages, 4485 KiB

Open AccessArticle

Thermally Assisted Grinding of Cassiterite Associated with Pollimetallic Ore: A Comparison between Microwave and Conventional Furnaces

by Chunlin He, Jian Zhao, Xiujuan Su, Shaojian Ma, Toyohisa Fujita, Yuezhou Wei, Jinlin Yang and Zongwu Wei

Minerals 2021, 11(7), 768; https://doi.org/10.3390/min11070768 - 15 Jul 2021

Cited by 3 | Viewed by 2269

Abstract

We investigated the influence of microwave and conventional heating pretreatments on the grinding of cassiterite associated with pollimetallic ore. The minerals that exhibited a stronger microwave absorption ability crushed first, which is the main difference between the microwave and the traditional heating pretreatments. [...] Read more.

We investigated the influence of microwave and conventional heating pretreatments on the grinding of cassiterite associated with pollimetallic ore. The minerals that exhibited a stronger microwave absorption ability crushed first, which is the main difference between the microwave and the traditional heating pretreatments. The distribution of Fe, Pb, Zn, and Sn increased in the fine size range (−0.425 mm). The Fe and Pb grades in the size ranges of −3.2 + 2 mm and −2 + 1 mm after the microwave pretreatment (6 kW, 1 min) were lower than those of the traditional heating (12 kW, 400 °C, 20 min), indicating that the microwave selective heating was beneficial for pyrite and jamesonite. The grade and distribution of Sn decreased significantly in the size ranges of −3.2 + 2 mm and −2 + 1 mm and increased in the size ranges of −0.425 + 0.15 mm and −0.15 + 0.074 mm. Microwave heating treatment promoted the grinding of sulfide ore and reduced the cassiterite overgrinding. Full article

(This article belongs to the Topic Advances in Separation and Purification Techniques)

► Show Figures

Figure 1

26 pages, 96100 KiB

Open AccessArticle

Crystal Chemistry of Six Grossular Garnet Samples from Different Well-Known Localities

by Sytle M. Antao

Minerals 2021, 11(7), 767; https://doi.org/10.3390/min11070767 - 15 Jul 2021

Cited by 4 | Viewed by 3379

Abstract

Two isotropic grossular (ideally Ca₃Al₂Si₃O₁₂) samples from (1) Canada and (2) Tanzania, three optically anisotropic grossular samples (3, 4, 5) from Mexico, and one (6) anisotropic sample from Italy were studied. The crystal structure of [...] Read more.

Two isotropic grossular (ideally Ca₃Al₂Si₃O₁₂) samples from (1) Canada and (2) Tanzania, three optically anisotropic grossular samples (3, 4, 5) from Mexico, and one (6) anisotropic sample from Italy were studied. The crystal structure of the six samples was refined in the cubic space group

I a \bar{3} d

, using monochromatic synchrotron high-resolution powder X-ray diffraction (HRPXRD) data and the Rietveld method. The compositions of the samples were obtained from electron microprobe analyses (EPMA). The HRPXRD traces show a single cubic phase for two isotropic samples, whereas the four anisotropic samples contain two different cubic phases that were also resolved using X-ray elemental line scans, backscattered electron (BSE) images, and elemental maps. Structural mismatch from two cubic phases intergrown in the birefringent samples gives rise to strain-induced optical anisotropy. Considering the garnet general formula, ^[8]X₃^[6]Y₂^[4]Z₃^[4]O₁₂, the results of this study show that with increasing unit-cell parameter, the Y-O distance increases linearly and rather steeply, the average <X-O> distance increases just slightly in response to substitution mainly on the Y site, while the Z-O distance remains nearly constant. The X and Z sites in grossular contain Ca and Si atoms, respectively; both sites show insignificant substitutions by other atoms, which is supported by a constant Z-O distance and only a slight increase in the average <X-O> distance. The main cation exchange is realized in the Y site, where Fe³⁺ (ionic radius = 0.645 Å) replaces Al³⁺ (ionic radius = 0.545 Å), so the Y-O distance increases the most. Full article

(This article belongs to the Special Issue Selected Papers from the 2nd International Electronic Conference on Mineral Science)

► Show Figures

Figure 1

25 pages, 10840 KiB

Open AccessArticle

Alterations and Contaminations in Ceramics Deposited in Underwater Environments: An Experimental Approach

by Uxue Sanchez-Garmendia, Javier G. Iñañez and Gorka Arana

Minerals 2021, 11(7), 766; https://doi.org/10.3390/min11070766 - 15 Jul 2021

Cited by 3 | Viewed by 2935

Abstract

Ancient ceramics recovered after a long burial period have probably undergone several alterations and contaminations, introducing a chemical variability, affecting the ceramic’s natural variability. That is, the chemical and the mineralogical compositions of the ceramic pastes after their deposition will not be the [...] Read more.

Ancient ceramics recovered after a long burial period have probably undergone several alterations and contaminations, introducing a chemical variability, affecting the ceramic’s natural variability. That is, the chemical and the mineralogical compositions of the ceramic pastes after their deposition will not be the same as they originally were. Therefore, it is known that the alteration and contamination processes, and the discrimination of some elements, should be considered when studying the ceramics to avoid incorrect interpretations about their provenance, technology and the use of the artefact, as well as its proper preservation. In the present work, the authors performed an experimental approach in order to study the alterations and contaminations that occurred in 60 ceramic cylinders buried in two different underwater environments. Once the pieces were taken out from the water environments, they were characterized by a multi-analytical approach. For this purpose, inductively coupled plasma mass spectrometry (ICP-MS), X-ray diffraction (XRD), scanning electron microscopy–energy dispersive spectrometry (SEM–EDS) and Raman spectroscopy were used. Newly formed minerals of different forms have been identified, with different crystallization grades. Some examples are the needles, flakes, sponges and long and short prisms composed of several elements such as Ca, F, S and O. Full article

(This article belongs to the Special Issue Archaeological Ceramic Diagenesis)

► Show Figures

Figure 1

16 pages, 4789 KiB

Open AccessFeature PaperArticle

Ore Genesis of the Takatori Tungsten–Quartz Vein Deposit, Japan: Chemical and Isotopic Evidence

by Yuichi Morishita and Yoshiro Nishio

Minerals 2021, 11(7), 765; https://doi.org/10.3390/min11070765 - 15 Jul 2021

Cited by 8 | Viewed by 3208

Abstract

The Takatori hypothermal tin–tungsten vein deposit is composed of wolframite-bearing quartz veins with minor cassiterite, chalcopyrite, pyrite, and lithium-bearing muscovite and sericite. Several wolframite rims show replacement textures, which are assumed to form by iron replacement with manganese postdating the wolframite precipitation. Lithium [...] Read more.

The Takatori hypothermal tin–tungsten vein deposit is composed of wolframite-bearing quartz veins with minor cassiterite, chalcopyrite, pyrite, and lithium-bearing muscovite and sericite. Several wolframite rims show replacement textures, which are assumed to form by iron replacement with manganese postdating the wolframite precipitation. Lithium isotope ratios (δ⁷Li) of Li-bearing muscovite from the Takatori veins range from −3.1‰ to −2.1‰, and such Li-bearing muscovites are proven to occur at the early stage of mineralization. Fine-grained sericite with lower Li content shows relatively higher δ⁷Li values, and might have precipitated after the main ore forming event. The maximum oxygen isotope equilibrium temperature of quartz–muscovite pairs is 460 °C, and it is inferred that the fluids might be in equilibrium with ilmenite series granitic rocks. Oxygen isotope ratios (δ¹⁸O) of the Takatori ore-forming fluid range from +10‰ to +8‰. The δ¹⁸O values of the fluid decreased with decreasing temperature probably because the fluid was mixed with surrounding pore water and meteoric water. The formation pressure for the Takatori deposit is calculated to be 160 MPa on the basis of the difference between the pressure-independent oxygen isotope equilibrium temperature and pressure-dependent homogenization fluid inclusions temperature. The ore-formation depth is calculated to be around 6 km. These lines of evidence suggest that a granitic magma beneath the deposit played a crucial role in the Takatori deposit formation. Full article

(This article belongs to the Special Issue Mineralogy, Geochemistry and Geochronology of W-Sn Polymetallic Deposits)

► Show Figures

Figure 1

14 pages, 2817 KiB

Open AccessArticle

Competing Sorption of Se(IV) and Se(VI) on Schwertmannite

by Bouchra Marouane, Ning Chen, Martin Obst and Stefan Peiffer

Minerals 2021, 11(7), 764; https://doi.org/10.3390/min11070764 - 15 Jul 2021

Cited by 5 | Viewed by 2726

Abstract

Schwertmannite (SHM) is a naturally occurring mineral that has been shown to effectively scavenge oxyanions from contaminated water. In this study, Fourier-transform infrared spectroscopy and X-ray absorption spectroscopy techniques in combination with wet-chemical techniques were used to study the competitive sorption of Se(IV) [...] Read more.

Schwertmannite (SHM) is a naturally occurring mineral that has been shown to effectively scavenge oxyanions from contaminated water. In this study, Fourier-transform infrared spectroscopy and X-ray absorption spectroscopy techniques in combination with wet-chemical techniques were used to study the competitive sorption of Se(IV) and Se(VI) at pH 3. The experiments were conducted with three types of schwertmannite obtained from oxidative synthesis, biogenic synthesis and high-pressure compaction at different initial Se concentrations and mixing ratios for 48 h and 56 days, respectively. A threshold value for the uptake mechanisms was identified, which reflects the amount of easily exchangeable sulphate (~0.5 mmol/g). At adsorbate concentrations below this threshold, an inner-sphere corner-sharing bidentate binuclear complex forms upon exchange with sulphate. At higher concentrations, both oxyanions become bound to SHM through co-occurrence of mainly inner-sphere and partly outer-sphere corner-sharing bidentate binuclear complexes with Fe(III) containing surface sites. Single species experiments clearly indicate a higher affinity of SHM for Se(IV). However, in mixed species experiments, competitive sorption occurs with equal or even preferential uptake of Se(VI) at concentrations much lower than the threshold value, presumably due to geometrical similarity between selenate and sulphate, and increasing preference for Se(IV) at high Se concentrations. Full article

(This article belongs to the Special Issue Mineral Surface Reactivity with Application to Contaminant Retention and Element Partitioning)

► Show Figures

Figure 1

16 pages, 9457 KiB

Open AccessFeature PaperArticle

Evolution of Sedimentary Basins as Recorded in Silica Concretions: An Example from the Ionian Zone, Western Greece

by Georgia Pe-Piper, David J. W. Piper, Nicolina Bourli and Avraam Zelilidis

Minerals 2021, 11(7), 763; https://doi.org/10.3390/min11070763 - 15 Jul 2021

Cited by 6 | Viewed by 3133

Abstract

Chert concretions in thick limestone successions preserve a more complete paragenetic sequence of diagenetic minerals than their host limestone and interbedded shale. The goal of this study was to test the possible presence of a high-temperature mineralising system in the Ionian basin of [...] Read more.

Chert concretions in thick limestone successions preserve a more complete paragenetic sequence of diagenetic minerals than their host limestone and interbedded shale. The goal of this study was to test the possible presence of a high-temperature mineralising system in the Ionian basin of western Greece. Upper Cretaceous chert nodules were sampled at Araxos, where rocks are highly faulted and uplifted by salt diapirism, and on Kastos Island, on the flanks of a regional anticline. Chert concretions have microporosity produced by recrystallisation of opal to quartz and fractures produced in the brittle chert during basin inversion. Diagenetic mineral textures were interpreted from backscattered electron images, and minerals were identified from their chemistry. Diagenetic minerals in pores and veins include sedimentary apatite (francolite), dolomite, Fe-chlorite, Fe oxide-hydroxide mixtures, sphalerite, barite and calcite. Sphalerite is restricted to Araxos, suggesting that inferred basinal fluids were hotter and more saline than at Kastos. At Araxos, the Fe oxide-hydroxide also includes minor Cu, Zn, and Ni. Whether the transported metals were derived from sub-salt clastic rocks and basement, or from enriched Mesozoic black shales, is unclear. The effectiveness of this novel approach to understanding fluid flow history in thick limestone successions is validated. Full article

(This article belongs to the Special Issue The Mineralogy of the Siliceous Concretions)

► Show Figures

Graphical abstract

21 pages, 9824 KiB

Open AccessArticle

Transport Direction and Scandinavian Source Regions of the Saalian Glacial and Glaciofluvial Deposits in a Case Study of Łubienica-Superunki (Central Poland)

by Maria Górska-Zabielska, Ewa Smolska and Lucyna Wachecka-Kotkowska

Minerals 2021, 11(7), 762; https://doi.org/10.3390/min11070762 - 14 Jul 2021

Cited by 2 | Viewed by 2189

Abstract

The article contains detailed petrographic studies, which covered a coarse and medium-grain gravel fraction of two layers of glacial till (units ŁS II and ŁS IV) and two layers of sand-gravelly outwash deposits (units ŁS I and ŁS III) related to the Odranian [...] Read more.

The article contains detailed petrographic studies, which covered a coarse and medium-grain gravel fraction of two layers of glacial till (units ŁS II and ŁS IV) and two layers of sand-gravelly outwash deposits (units ŁS I and ŁS III) related to the Odranian Glaciation (MIS6, Saalian) in Łubienica-Superunki, North Mazovian Lowland, central Poland. Additionally, the indicator erratics were identified to indicate their Scandinavian source areas and the directions of the ice sheet transgressions. This case study is discussed against the background of similar sediments and forms from the same age but from other places in the Polish Lowlands. Regardless of the facies types and fractions, crystalline rocks dominated over all other petrographic groups in all samples. The most common were the indicator erratics derived from the Åland Islands, followed by those from the south-eastern area of Sweden (Småland) and from Dalarna in central Sweden. Amongst the erratics of limited indicative significance, the most common were Lower Palaeozoic limestones and the Jotnian red sandstones. The complex petrographic analyses point to the dipartite nature of the studied profile. This separateness was confirmed by the TBC: 59.1–59.2° N and 18.0–18.2° E for the lower units and 58.8–59.4° N and 17.3–17.9° E for the upper ones. Full article

(This article belongs to the Special Issue Provenance Analysis of Clastics Applied to Sedimentary Geology and Petrology)

► Show Figures

Figure 1

16 pages, 7756 KiB

Open AccessArticle

What Affects Dewatering Performance of High Density Slurry?

by Yunhui Li, Heather Kaminsky, Xue Yuki Gong, Yijia Simon Sun, Mohammed Ghuzi and Ardalan Sadighian

Minerals 2021, 11(7), 761; https://doi.org/10.3390/min11070761 - 14 Jul 2021

Cited by 4 | Viewed by 2881

Abstract

The dewatering of flocculated high density slurry presents a significant challenge to most mining industries. The new technologies to treat high density slurry require a consistent and robust flocculation method in order to enter the market of tailings management. The flocculation of high [...] Read more.

The dewatering of flocculated high density slurry presents a significant challenge to most mining industries. The new technologies to treat high density slurry require a consistent and robust flocculation method in order to enter the market of tailings management. The flocculation of high density slurry, however, due to its complexity, is always a challenge to be undertaken appropriately and to evaluate the dewatering performance correctly. This paper probes the complexity by using a torque-controlled mixing technique to demonstrate the influence of feed properties, polymer type, polymer dosage, and mixing conditions on dewatering performance. The study shows that flocculant should be dosed at the optimal range to achieve the highest dewatering performance. A full dosage responsive curve including under dosage, optimal dosage, and overdosage is critical to evaluate the dewatering performance of high density slurries and flocculants. The mixing conditions such as mixing speed, mixing time, and geometry of the mixing impeller affect the flocculation efficacy. It was found that the dewatering performance of high density slurry is sensitive to solids content, water chemistry, and clay activity. High sodicity and high clay activity in the high density slurry decreases the dewatering performance. Therefore, it is critical to evaluate flocculants across multiple feeds and dosages with replication in order to select optimal dewatering performance. Using multiple key performance indicators (KPIs) to build technical and economic criteria is also critical for polymer evaluation. Full article

(This article belongs to the Special Issue Flocculation Process of Tailings)

► Show Figures

Figure 1

33 pages, 7006 KiB

Open AccessArticle

Halogens in Eclogite Facies Minerals from the Western Gneiss Region, Norway

by Lewis Hughes, Simon Cuthbert, Alex Quas-Cohen, Lorraine Ruzié-Hamilton, Alison Pawley, Giles Droop, Ian Lyon, Romain Tartèse and Ray Burgess

Minerals 2021, 11(7), 760; https://doi.org/10.3390/min11070760 - 14 Jul 2021

Cited by 6 | Viewed by 3323

Abstract

Ultra-high-pressure (UHP) eclogites and ultramafites and associated fluid inclusions from the Western Gneiss Region, Norwegian Caledonides, have been analysed for F, Cl, Br and I using electron-probe micro-analysis, time-of-flight secondary ion mass spectrometry and neutron-irradiated noble gas mass spectrometry. Textures of multi-phase and [...] Read more.

Ultra-high-pressure (UHP) eclogites and ultramafites and associated fluid inclusions from the Western Gneiss Region, Norwegian Caledonides, have been analysed for F, Cl, Br and I using electron-probe micro-analysis, time-of-flight secondary ion mass spectrometry and neutron-irradiated noble gas mass spectrometry. Textures of multi-phase and fluid inclusions in the cores of silicate grains indicate formation during growth of the host crystal at UHP. Halogens are predominantly hosted by fluid inclusions with a minor component from mineral inclusions such as biotite, phengite, amphibole and apatite. The reconstructed fluid composition contains between 11.3 and 12.1 wt% Cl, 870 and 8900 ppm Br and 6 and 169 ppm I. F/Cl ratios indicate efficient fractionation of F from Cl by hydrous mineral crystallisation. Heavy halogen ratios are higher than modern seawater by up to two orders of magnitude for Br/Cl and up to three orders of magnitude for I/Cl. No correlation exists between Cl and Br or I, while Br and I show good correlation, suggesting that Cl behaved differently to Br and I during subduction. Evolution to higher Br/Cl ratios is similar to trends defined by eclogitic hydration reactions and seawater evaporation, indicating preferential removal of Cl from the fluid during UHP metamorphism. This study, by analogy, offers a field model for an alternative source (continental crust) and mechanism (metasomatism by partial melts or supercritical fluids) by which halogens may be transferred to and stored in the sub-continental lithospheric mantle during transient subduction of a continental margin. Full article

(This article belongs to the Special Issue Behaviour of Volatiles and Fluid-Mobile Elements in Subduction Zones)

► Show Figures

Figure 1

29 pages, 9497 KiB

Open AccessArticle

Polyphase Deformation of the High-Grade Metamorphic Rocks along the Neusspruit Shear Zone in the Kakamas Domain: Insights into the Processes during the Namaquan Orogeny at the Eastern Margin of the Namaqua Metamorphic Province, South Africa

by Cyrille Stephane Tsakou Sonwa, Jan van Bever Donker and Russell Bailie

Minerals 2021, 11(7), 759; https://doi.org/10.3390/min11070759 - 14 Jul 2021

Viewed by 4033

Abstract

The central part of the Namaqua Metamorphic Province was subjected to intense deformation under high-grade metamorphic conditions up to granulite facies, but also shows greenschist facies overprints denoting the metamorphic nature during the 1.2–1.0 Ga Namaquan Orogeny. This study examines the structural development [...] Read more.

The central part of the Namaqua Metamorphic Province was subjected to intense deformation under high-grade metamorphic conditions up to granulite facies, but also shows greenschist facies overprints denoting the metamorphic nature during the 1.2–1.0 Ga Namaquan Orogeny. This study examines the structural development of the central Kakamas Domain of the eastern Namaqua Metamorphic Province, which has not been extensively studied previously. The compressional orogenic phase is associated with D₁ and D₂ deformation events during which northeast–southwest-directed shortening resulted in southwest-directed thrusting illustrated by an intra-domain thrust and southwest-verging isoclinal folds. The post-tectonic Friersdale Charnockite of the Keimoes Suite is emplaced during the D₃ deformation event. Late reactivation of the intra-domain thrust in the Kakamas Domain to form the Neusspruit Shear Zone during the D₄ event is of a monoclinic nature and is described as a deeply rooted structure with shear direction towards the east. This structure, together with the more local Neusberg Thrust Fault, forms part of an intensely flattened narrow basin in the eastern Namaqua Metamorphic Province. Strain and vorticity indices suggest a transpressional shearing across the Neusspruit Shear Zone and adjacent regions probably initiated during the reactivation of the intra-domain thrust. The ~1.2 to 1.8 km-wide, northwest–southeast striking dextral-dominated Neusspruit Shear Zone constitutes a western regional boundary for the supracrustal Korannaland Group and is composed of steep, narrow zones of relatively high strain, characterised by ductile deformation and penetrative strain. Full article

(This article belongs to the Special Issue The Tectono-Metamorphic Evolution of the Namaqua Metamorphic Province)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Minerals, Volume 11, Issue 7 (July 2021) – 130 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI