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The application of first-principles calculations for predicting lattice thermal conductivity (LTC) in crystalline materials, in conjunction with the linearized phonon Boltzmann equation, has gained increasing popularity. In this calculation, the determination of force constants through first-principles calculations is critical for accurate LTC predictions. For material exploration, performing first-principles LTC calculations in a high-throughput manner is now expected, although it requires significant computational resources. To reduce computational demands, we integrated polynomial machine learning potentials on-the-fly during the first-principles LTC calculations. This paper presents a systematic approach to first-principles LTC calculations. We designed and optimized an efficient workflow that integrates multiple modular software packages. We applied this approach to calculate LTCs for 103 compounds of wurtzite, zinc blende, and rocksalt types to evaluate the performance of the polynomial machine learning potentials in LTC calculations. We demonstrate a significant reduction in the computational resources required for the LTC predictions. [ABSTRACT FROM AUTHOR]

In this work, the value and the polarity of the spontaneous and piezoelectric polarization have been investigated, as the use of two different reference structures for wurtzite-type group-III nitrides, namely, the zinc-blende and the layered-hexagonal crystal lattice, have resulted in different predictions. It was found that although the differences in value and polarity of the polarization for heterostructures such as wurtzite Al1−xScxN/GaN lead to similar interface sheet charges, a significant mismatch is observed when polarization reversal is considered. The interface sheet charge predicted before and after the polarization reversal in the wurtzite Al1−xScxN layer on GaN using the zinc-blende lattice as a reference predominantly shows a change in sign. When using the layered-hexagonal lattice as a reference, not only is the same polarity of the interface sheet charge maintained after polarization reversal, but it is even 30 times larger. In this case, the giant and positive spontaneous polarization values for metal-polar Al1−xScxN extracted from the ferroelectric switching, as well as the alignment of the piezoelectric polarization to it, were observed to be consistent with the predictions referenced to the layered-hexagonal lattice. Thus, it is concluded that the layered-hexagonal reference is not only more suitable for predicting the ferroelectric properties of wurtzite Al1−xScxN but should also be the correct reference when considering polarization reversal in heterostructures. If the significant increase in the interface sheet charge after polarization reversal is experimentally detected, it will allow the design and fabrication of novel devices for future high-frequency and power electronics applications. [ABSTRACT FROM AUTHOR]

This Tutorial provides a comprehensive overview of various k ⋅ p models used to describe the electronic band structures of semiconductors with cubic diamond and zinc blende symmetries. Our primary focus is on III–V semiconductors, with a particular emphasis on highly mismatched alloys. We begin our exploration with the six-band k ⋅ p model, which effectively captures interactions within the highest valence bands. Following that, we delve into the intricacies of the eight-band k ⋅ p model, which takes into account strain effects and modifications to energy dispersion. The Tutorial also introduces the band anticrossing model and its corresponding ten-band k ⋅ p models, specifically tailored for dilute nitride semiconductors. Furthermore, we extend our discussion to the valence band anticrossing model and its application to the 14-band k ⋅ p model in the context of dilute bismide materials. Additionally, we emphasize the significance of more comprehensive models, exemplified by the 30-band k ⋅ p model, for faithfully representing the entire Brillouin zone. [ABSTRACT FROM AUTHOR]

Cadmium (Cd)-bearing sphalerite (SP, ZnS) and smithsonite (SM, ZnCO 3) particulate matter (PM) is deposited on soils near carbonate-hosted Zn ore deposits. Whether and how carbonate rocks such as limestone influence the mobility of Cd and Zn in soils is largely unknown. For this reason, we conducted a soil incubation experiment to investigate the chemical and mineralogical changes in soil–soil solution samples, including the occurrence of Cd- and Zn-bearing colloids and nanoparticles. Here the addition of calcite to SP- and SM-spiked soils promoted the formation of Cd- and Zn- bearing nanoparticles and colloids and thus significantly decreased the concentrations of Cd and Zn in soil solutions. Transmission electron microscope and extended X-ray absorption fluorescence spectroscopy showed that the addition of calcite resulted in the formation of Fe-OM-Ca colloids (OM = organic matter), sequestrating Cd and Zn. Furthermore, the release of Ca2+ during the dissolution of calcite promoted the aggregation of colloids and thus decreased the mobility of Cd- and Zn-bearing colloids in the soil column. The addition of calcite also decreased the amount of Cd and Zn released from the dissolution of SP and SM through the formation of calcite nano-layers armoring particles of the SP and SM phases. This study provides new insights into the environmental fate of particulate Cd and Zn in soils around carbonate-hosted Pb-Zn ore deposits. Specifically, it shows that the formation and aggregation of Cd- and Zn-bearing colloids decrease the mobility and bioavailability of both elements. [ABSTRACT FROM AUTHOR]

The Early Cretaceous Halasheng deposit, located in the southern Erguna Block, is an intermediate sulfidation epithermal Ag-Pb-Zn deposit in the Derbugan metallogenic belt. The Halasheng deposit comprises both proximal skarn mineralization and distal hydrothermal vein-type Pb-Zn-Ag mineralization, which can be further divided into three stages represented by Fe-As-S, Pb-Zn-Cu-Fe-S, and Ag-Pb-Zn-Sb-S element associations. The main ore minerals in the Halasheng deposit include galena, sphalerite, pyrite, arsenopyrite, chalcopyrite, bournonite, falkmanite, and argentiferous minerals. Visible silver in the form of independent argentiferous minerals, mainly including freibergite, polybasite, stromeyerite, pyrargyrite, acanthite, and native silver, is the major type of silver occurring in the Halasheng district. Fluid inclusion studies of sphalerite and quartz from different mineralization stages revealed that skarn mineralization has the relatively highest homogenization temperature (322~398 °C), while in the vein-type hydrothermal mineralization stage, the homogenization temperature has a declining trend from the early stage to late stage (from 300~350 °C to 145~236 °C). In the whole mineralization process, the salinity of ore-forming fluids is almost constant at a relatively high level (10.5~21.9 wt% NaCl). Fluid cooling, or fluid–wallrock reaction, is supposed to be the major cause of metal precipitation in the Halasheng deposit. Through an analogy with the typical Ag-Pb-Zn deposits in the Derbugan metallogenic belt, it is suggested that the discovered orebodies in the Halasheng deposit likely belong to the shallow part of the epithermal system, and there is high potential to discover Zn, Cu-Zn orebodies, and even porphyry Mo-Cu mineralization. In terms of regional ore prospecting, Early Cretaceous intermediate-acid intrusions have the potential to form related Ag-Pb-Zn deposits and should receive special attention. Furthermore, places where Lower Cambrian marbles are exposed or concealed are favorable settings for skarn mineralization. [ABSTRACT FROM AUTHOR]

Many interesting materials in a broad range of applications have in their composition the coexistence of zinc and iron. Their characterization by XPS should identify and quantify both elements. The most intense regions for these elements Zn 2p and Fe 2p are, therefore, used to accomplish that purpose. By using sphalerite as an example of a material where Zn and Fe may coexist and using XPS with two different X radiation sources to study them, it is demonstrated that the Fe 2p region, when the iron is the minor component, may be seriously affected by the Auger Zn L3M1M23 structure. The sphalerite (Zn1−xFexS) here studied has x ≈ 0 and is a good example to show how an XPS spectrum obtained with the X-ray Al Kα, the most used radiation in monochromatic equipment, leads to a wrong assignment of the structures existing in the binding energy region of Fe 2p. The simultaneous use of Mg Kα radiation showed that the Fe 2p is below the XPS detection in this specific sample of sphalerite. Its attested absence reveals that the structure detected, when using Al Kα in the "Fe 2p" region, is assigned to a zinc Auger multiple peak and not to the expected 2p photoelectron doublet peak of iron. [ABSTRACT FROM AUTHOR]

CuS nanoparticles (Np) were synthesized and deposited on synthetic sphalerite (SP) using two different methods. Two nanoparticle products were obtained on the surface of SP, Np1 and Np2, resulting in two active materials (Np1-SP and Np2-SP) with specific characteristics. Nanoparticles and active materials were characterized by TEM, XRD, SEM, and XPS. The collectors PAX and SIPX were adsorbed on Np1-SP and Np2-SP to determine the adsorption capacity. Method 1 provides a higher quantity of nanoparticles on SP, which allows for the adsorption of a higher amount of SIPX. Method 1 was used to deposit nanoparticles on two natural sphalerites (SN) with different iron contents. SN, unlike SP, can be used to test nanoparticle activation results in microflotation experiments. SN was activated with nanoparticles (Np1-SN) and using the traditional method (Cu-SN). The recovery of 75% of zinc using the microflotation process suggests that the hydrophobicity of Np1-SN is higher than that of Cu-SN. Nanoparticles improve the hydrophobicity of SN compared to the traditional activation used in the mining industry. These results suggest that using nanoparticles is an excellent option to activate minerals in flotation processes, decreasing the consumption of reagents and helping to mitigate negative impacts on the environment. [ABSTRACT FROM AUTHOR]

Sphalerite is the main Zn ore mineral and is the primary source of Cd, Ge and In, and a minor source of Ga. Owing to a shift from fossil fuel to renewable energy sources, these four minor elements have progressively become more important to the economy. Despite this, resources of Cd, Ga, Ge and In are rarely reported, as these metals are not considered material to the economics of resource development. As a result, the distribution of these elements between and within deposits is poorly known, and national and international resources are largely unreported. Following previous studies, we have compiled analytical data for Cd, Ga, Ge and In from sphalerite and used global and local ore geochemical datasets to assess geochemical controls on the concentration of these elements in Zn deposits. Our results are similar to those of previous studies and suggest that lower-temperature deposits are enriched in Ge, whereas higher-temperature deposits are enriched in In. However, modelling of hydrothermal geochemistry indicates other factors are important in concentrating these metals. In particular, the oxidation state of the fluid (oxidised vs reduced) and the depositional mechanisms also have a strong influence in Ga, Ge and In enrichment. Reduction of oxidised fluids is particularly effective in depositing Ge, whereas cooling very effectively deposits In and, in some cases, Ge. As a consequence, some higher-temperature deposits (e.g. high sulfidation epithermal and some volcanic-hosted massive sulfide) can be Ge-enriched, and some lower-temperature deposits (e.g. siliciclastic–carbonate shale-hosted deposits) can be enriched in In. Using the existing ore geochemical data and calculated characteristic Ge/Zn and In/Zn ratios, indicative estimates have been made on the endowment of Australian Zn deposits of Ge and In. These estimates highlight the potential of the North Australian Zinc Belt for Ge and for VHMS deposits for In. Although there is a large amount of uncertainty in the estimates, they are indicative of the potential for these metals in Australia. KEY POINTS: The efficacy of metal leaching from regional alteration zones depends on the temperature of alteration and the alteration minerals. For example, low-temperature (<200 °C) chlorite-rich zones tend to sequester zinc, whereas zinc is leached from higher-temperature, chlorite-rich zones. The concentrations of Ga, Ge and In in sphalerite and zinc ores depend not only on temperature but also on the redox state of the ore fluids and sphalerite depositional mechanisms. The endowment of Ge, In and other critical minerals in zinc deposits can be/has been estimated using typical (median) ratios of these elements to zinc for individual deposits or deposit types and zinc endowments of individual deposits. [ABSTRACT FROM AUTHOR]

In seawater flotation, some chemical properties of seawater affect the flotation separation of chalcopyrite and sphalerite. Using seawater instead of fresh water to separate copper – zinc can save fresh water resources and reduce lime consumption, which has broad prospects in terms of economic and environmental protection. In this paper, the flotation separation behavior of chalcopyrite and sphalerite in seawater was tested and the mechanism was analyzed. As a contrast, the copper grade of concentrate in seawater flotation declined from 23.7% to 22.6%. Meanwhile, the recovery of chalcopyrite declined from 66.2% to 42.8% and the SI value declined from 2.210 to 1.599. With the addition of sodium hexametaphosphate, sodium silicate and EDTA, the SI value increased from 1.599 to 2.176, 2.238 and 2.096, respectively. Nevertheless, when EDTA was excessive, the SI value was only 1.998. This indicated that excessive EDTA is unfavorable to flotation separation of chalcopyrite from sphalerite. Wettability analysis, zeta potential analysis, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, density functional theory calculation and E-DLVO calculation verified the flotation separation behavior and revealed the mechanism. [ABSTRACT FROM AUTHOR]

Jumun Island is tectonostratigraphically situated on the marginal zone of the Gyeonggi Massif. The Massif is in contact with the southwestern margin of the Imjingang Belt and adjacent to Boreum Island, where ultramafic rock with magmatic Fe-Ti oxide deposits occurs. The northwest of Jumun Island, facing the Boreum ultramafic rock with Fe-Ti oxide ores, is composed of Precambrian Boreumdo schists containing a few magmatic intrusives, the exact ages of which are unknown. In Jumun, the ultramafic intrusion (Mg# = 75), which is confined to a narrow zone along the seaside, mainly consists of olivine (Fo = 81–82), amphibole (magnesio-horn-blende to tremolite), and phlogopite. The olivine is strongly serpentinized and encompassed by amphibole and phlogopite. The Ni-Cu sulfide mineralization found in the ultramafic rock is weak but has a typical assemblage of pyrrhotite-pentlandite-chalcopyrite with a small amount of magnetite. Notably, the Ni-Cu sulfides are closely associated with amphibole and phlogopite and are found in the fractures and interstitials of the olivine grains. The pyrrhotite (n = 2) and chalcopyrite (n = 1) are compositionally close to pure samples, whereas the pentlandite (n = 2) is characterized by enrichment with Co (up to 6.9 wt%). The sphalerite-bearing quartz vein cuts across the Precambrian gneissic rock and strikes N70 °W with an 80 °NE dip. This vein, which is traceable to a limited extent and approximately 40 cm wide, shows mineralogical zonation in the inward direction from pyrite to sphalerite-dominant. Consisting of sphalerite, pyrite, quartz, and chlorite with minor amounts of chalcopyrite, pyrrhotite, and pentlandite, it is composed of 9.56 wt% Zn with < 1.0 wt% As, Co, Cu, In, Mn, Ni, and Pb and below-detection limits (0.001 ppm) amounts of Bi, Ge, Mo, Se, Sb, Te, and W. Sphalerite, a principal ore mineral, is coarse-grained and reddish-brown and is composed of 57.3–58.8 wt% ZnS, 8.0–9.2 wt% FeS, and 32.0–32.4 wt% S with small amounts of Cu, Mn, As, and Cd. The recently discovered Ni-Cu sulfide mineralization and quartz vein with sphalerite, along with the linear array of magmatic Fe-Ti oxide deposits, provide conclusive evidence that the marginal zone of the Gyeonggi Massif may be a geologically favorable area for the formation of magmatic and magmatic-hydrothermal deposits. For exploration purposes, it is necessary to contextualize the source, tectonic setting, and magmatic evolution. [ABSTRACT FROM AUTHOR]

Mineralization temperature determination is fundamental to economic geology research, yet quantifying it across mineralization remains a challenge. Sphalerite is ubiquitous in various types of mineral deposits and particularly abundant in Pb–Zn deposits, and its trace element composition is temperature-dependent, making it an ideal candidate for geothermometry. Here, we first compiled a global sphalerite trace element composition dataset (n = 1416, T = 75–430 °C), encompassing different Pb–Zn deposit types (Mississippi Valley-type, epithermal, sedimentary-exhalative, skarn-type, and volcanic massive sulfide deposits). After data processing following statistical norms, the different machine learning algorithms (random forest (RF), gradient boosted decision trees, artificial neural networks, least absolute shrinkage and selection operator, support vector machine, k-nearest neighbors, and linear regression) were employed to train different models to explore the potential link between the sphalerite-forming temperature and trace element geochemistry. Each of the model's performance was evaluated using the leave-one-out cross-validation approach, which revealed the RF (R2 = 0.88, RMSE = 26 °C) as the best-performing algorithm. Meanwhile, five-fold cross-validation results indicated that the RF model (R2 = 0.87, RMSE = 25 °C) outperformed the GGIMFis thermometer (R2 = 0.53, RMSE = 50 °C). Meanwhile, the feature importance analysis revealed that Ge and Mn displayed significant impacts on temperature prediction as the high temperature generally favors Mn, but not Ge, incorporation into the sphalerite structure. Finally, a model was trained with the entire dataset, generating a reliable sphalerite thermometer (SPRFT software, freely provided here) suitable for low to moderate temperature (75–430 °C) hydrothermal environments. This SPRFT thermometer was applied to evaluate the temperature of Pb–Zn mineralization in the Sichuan–Yunnan–Guizhou Pb–Zn metallogenic belt (SW China) and it provides an innovative perspective into the ore-fluid evolution. This study demonstrated a robust approach for calculating mineralization temperatures using machine learning. This novel methodology opens new avenues for investigating and recalculating more mineral geothermometers. [ABSTRACT FROM AUTHOR]

CdS quantum dots (QDs) have been extensively studied as photocatalysts and sensitizers for visible-light-driven water reduction. However, their efficiencies are limited by the need to accumulate sufficient redox equivalents to produce H2 and consequent photocorrosion associated with slow hole-transfer rates. To address these limitations, we report the formation of CdS QD assemblies (aerogels, AGs) capable of facilitating energy/charge transport between individual QDs, and evaluate their performance as photocatalysts for hydrogen evolution as a function of structure, wurtzite (w-) vs. zincblende (zb-), and different annealing temperatures. The formation of AGs from QDs resulted in increased rates of H2 production under visible light illumination: from 1458 (QD) to 6650 (AG) µmolH2·h−1·g−1 on zbCdS and from 1221 (QD) to 3325 (AG) µmolH2·h−1·g−1 on wCdS. This is attributed to exciton delocalization between adjacent QDs facilitating charge/energy transport. Thermal processing of CdS AGs up to 250 °C improved their activity, increasing the degree of exciton delocalization, while annealing them to 300 °C caused sintering of the primary QD particles within the AGs and a decrease in activity associated with loss in surface area. The best photocatalyst, zbCdS AG annealed at 250°C, had an average H2 production rate of 13,604 ± 2017 µmolH2·h−1·g−1, an apparent quantum yield of 2.8% at 425 ± 12.5 nm, and was stable for 2 h before beginning to deactivate due to photocorrosion. This study confirms the potential of CdS AGs as matrixes for the design of more active and stable composite photocatalysts for water splitting. [ABSTRACT FROM AUTHOR]

InSb nanowires (NWs) show an important application in topological quantum computing owing to their high electron mobility, strong spin–orbit interaction, and large g factor. Particularly, ultra-thin InSb NWs are expected to be used to solve the problem of multiple sub-band occupation for the detection of Majorana fermions. However, it is still difficult to epitaxially grow ultra-thin InSb NWs due to the surfactant effect of Sb. Here, we develop an in-plane self-assembled technique to grow catalyst-free ultra-thin InSb NWs on Ge(001) substrates by molecular-beam epitaxy. It is found that ultra-thin InSb NWs with a diameter as small as 17 nm can be obtained by this growth manner. More importantly, these NWs have aspect ratios of 40–100. We also find that the in-plane InSb NWs always grow along the [110] and [ 1 1 ¯ 0 ] directions, and they have the same {111} facets, which are caused by the lowest-surface energy of {111} crystal planes for NWs grown with a high Sb/In ratio. Detailed structural studies confirm that InSb NWs are high-quality zinc blende crystals, and there is a strict epitaxial relationship between the InSb NW and the Ge substrate. The in-plane InSb NWs have a similar Raman spectral linewidth compared with that of the single-crystal InSb substrate, further confirming their high crystal quality. Our work provides useful insights into the controlled growth of in-plane catalyst-free III–V NWs. [ABSTRACT FROM AUTHOR]

Colloidal cadmium telluride (CdTe) nanoplatelets (NPLs) are promising materials for optoelectronic applications, such as photovoltaics and light-emitting diodes, due to their unique optical and electronic properties. However, controlling their growth, thickness, and stoichiometry remains challenging. This study explores the effect of synthesis temperature on the structural, optical, and stoichiometric properties of CdTe NPLs. CdTe NPLs were synthesized at temperatures of 170 °C, 180 °C, 190 °C, and 200 °C using colloidal methods. The resulting NPLs were characterized by UV–Vis absorption spectroscopy, photoluminescence (PL) spectroscopy, transmission electron microscopy (TEM), and total reflection X-ray fluorescence (TXRF) to assess their morphology, structure, and elemental composition. The results showed that the synthesis temperature significantly affected the NPL's morphology and stoichiometry. Optimal stoichiometry was achieved at 180 °C and 190 °C, with the crystal structure transitioning from zinc blende at lower temperatures to wurtzite at higher temperatures. Optical properties, including luminescence intensity and emission peaks, also varied with temperature. The synthesis temperature is an important parameter in controlling the structural and optical properties of CdTe NPLs. The optimal conditions for obtaining NPLs with the best characteristics were identified at 190 °C, presenting important findings for further optimization of CdTe NPL synthesis for optoelectronic applications. [ABSTRACT FROM AUTHOR]

This paper aims to investigate the behavior of LiMgN half-Heusler (HH) semiconductor doped by transition metals (TM  =  Mn, Fe, Co and Ni). HHs belong to the F 4 ̄ 3 m space group (No. 216) and have a zinc blende structure that can be described by the chemical symbol XYZ. The research methodology utilized in this investigation involves theoretical analysis based on the principles of density functional theory (DFT). The studied LiMg 0. 9 5 TM 0. 0 5 N alloy displayed the half-metallicity behavior when TM  =  Fe, Co and Ni. Hence, these systems could be a promising candidate in spintronic application thanks to their ferromagnetism. The principal contribution to magnetism in the full LiMg 0. 9 5 TM 0. 0 5 N alloys comes from the Mn, Fe, Co and Ni doping. The partial magnetic moments of these elements are significantly greater than the combined partial magnetic moments of Li, Mg and N. When comparing LiMg 0. 9 5 Mn 0. 0 5 N to LiMg 0. 9 5 Fe 0. 0 5 N, 5Co 0. 0 5 N and LiMg 0. 9 5 Ni 0. 0 5 N, it is important to note that the exchange splitting energy Δ (e + , e −) TM associated to their spin up and spin down were discussed. The variation of Mn(3d) in relation to ( e + , e − ) is larger than that of Fe, Co and Ni. Therefore, Δ (e + , e −) Mn > Δ (e + , e −) Fe > Δ (e + , e −) Co > Δ (e + , e −) Ni . Furthermore, there is a correlation between the magnetic moment and electronegativity trend of the TM dopant. Specially, the electronegativity trend ( χ TM ) is well matched with the total spin moment trend, where χ Ni > χ Co > χ Fe > χ Mn . [ABSTRACT FROM AUTHOR]

The rapid recombination of photoinduced charge carriers in semiconductors fundamentally limits their application in photocatalysis. Herein, we report that a superlattice interface and S-scheme heterojunction based on Mn0.5Cd0.5S nanorods can significantly promote ultrafast charge separation and transfer. Specifically, the axially distributed zinc blende/wurtzite superlattice interfaces in Mn0.5Cd0.5S nanorods can redistribute photoinduced charge carriers more effectively when boosted by homogeneous internal electric fields and promotes bulk separation. Accordingly, S-scheme heterojunctions between the Mn0.5Cd0.5S nanorods and MnWO4 nanoparticles can further accelerate the surface separation of charge carriers via a heterogeneous internal electric field. Subsequent capture of the photoelectrons by adsorbed H2O is as fast as several picoseconds which results in a photocatalytic H2 evolution rate of 54.4 mmol·g−1·h−1 without any cocatalyst under simulated solar irradiation. The yields are increased by a factor of ~5 times relative to control samples and an apparent quantum efficiency of 63.1% at 420 nm is measured. This work provides a protocol for designing synergistic interface structure for efficient photocatalysis. Limited charge separation is a major challenge in creating efficient semiconductor photocatalysis. This work introduces a superlattice interface and S-scheme heterojunction for ultrafast charge separation and transfer in photocatalytic H2 evolution. [ABSTRACT FROM AUTHOR]

As challenges in precious and base metal exploration intensify due to the diminishing availability of high-grade ore deposits, rising demand, energy costs, and stricter regulations towards net-zero carbon activities, advanced techniques to enhance exploration efficiency are becoming increasingly critical. This study demonstrates the effectiveness of quantitative X-ray diffraction (QXRD) with Rietveld refinement, coupled with multivariate statistical analysis (including agglomerative hierarchical clustering, principal component analysis, and fuzzy analysis), in characterizing the complex mineralogy of strata-bound volcanic-associated limestone-skarn Zn-Pb-Ag-(Cu-Au)-type sulphide deposits (SVALS). Focusing on 113 coarse rejects from the Gumsberg project located in the Bergslagen mining district in central Sweden, the research identified five distinct mineralogical clusters corresponding to polymetallic base metal sulphide mineralization, its proximal alteration zones, and variably metamorphosed host rocks. The results reveal significant sulphide mineralization, ranging from disseminated to massive occurrences of sphalerite, pyrrhotite, pyrite, and galena, with trace amounts of secondary minerals like anglesite in certain samples indicating weathering processes. The study also identifies rare minerals such as armenite, often overlooked in traditional geological logging. These findings underscore the potential of QXRD to enhance resource estimation, optimize exploration strategies, and contribute to more efficient and sustainable mineral exploration programs. The accuracy of QXRD was cross-validated with geological logs and geochemical data, confirming its reliability as a mineralogical discrimination tool. [ABSTRACT FROM AUTHOR]

Sphalerite (ZnS) is a sulfide found in a large variety of ore deposits and is frequently hosted in metamorphic terranes that have undergone deformation and related recrystallization. However, the deformation mechanisms of sphalerite are still poorly understood because recrystallization evidence is barely visible under an optical microscope and may reflect complex and frequently multistage mechanisms. Furthermore, sphalerite may host up to a few thousands of parts per million of critical metals such as gallium (Ga), germanium (Ge), and indium (In). Metamorphic conditions and dynamic recrystallization may have induced local or total redistribution of these elements. Modern techniques such as electron backscattered diffraction analyses (EBSD) and laser-induced breakdown spectroscopy (LIBS) applied on sphalerite allow for the examination of grain boundaries, crystal-plastic deformation, and internal chemical diffusion, which classically reflect active deformation mechanisms. In this study, a microstructural and in situ chemical comparison between four sphalerite types (types 1, 2, 3, and 4) has been made for the first time. The four sphalerite types present different deformation imprints, although they are hosted in a similar geological setting: the Pyrenean Axial Zone and the Montagne Noire Variscan massifs (France). Based on EBSD and LIBS mapping, we describe two regional sphalerite growth stages composed of dark red crystals with polygonal shape (type 1, Bentaillou-Liat deposit) and light- to dark-brown euhedral crystals (type 3, Saint Salvy deposit). New investigation at microscale on sphalerite grains from the Saint-Salvy deposit shows late Cu-Ge-Ga enrichment not only in specific sector zonings but also along grain boundaries, growing crystal edges, and in low-angle misorientations or twin boundaries. Following a deformation event that probably occurred during the Pyrenean-Alpine orogeny, these two sphalerite mineralizations have both endured plastic deformation in a dislocation creep regime and dynamically recovered by subgrain rotation (SGR) mechanism. Two mechanisms of Cu-Ga-Ge spatial redistribution are observed and are key processes for the crystallization of Cu-Ga-Ge-rich minerals in sphalerite veins. The first mechanism involved the in situ redistribution of Cu-Ga-Ge contents from a pre-existing concentration in the sphalerite lattice (type 3, Arre deposit), creating Ge-sulfides (briartite), probably during Pyrenean-Alpine orogeny. Formation of this type of Ge-mineral may be related to solid-state diffusion processes. The second mechanism is associated with the circulation of a Cu-Ga-Ge-rich fluid in surrounding rocks. In the pre-existing polygonal sphalerite from Late-Variscan veins (type 2, Pale Bidau deposit), millimeter-size bands of small (<50 μm), recrystallized sphalerite grains are locally observed. Those domains contain inclusions of Cu (chalcopyrite) and Ga and Ge minerals (brunogeierite, carboirite). Fluid-induced diffusion in the polygonal sphalerite aggregates may occur with superimposed dynamic recrystallization, such as the Late-Variscan veins (type 2, Pale Bidau-type). During post-Variscan time, this fluid enriched in Cu-Ga-Ge largely circulated in the upper-crust of this Variscan terrane. This study highlights the key importance of coupled textural (EBSD) and in situ chemical analyses (LIBS) of diverse sphalerite types at a regional scale to indirectly unravel the origin of vein mineralization, and their related critical metal distribution. [ABSTRACT FROM AUTHOR]

Copyright of Geology & Exploration is the property of Geology & Exploration Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In response to the occurrence of selective grinding phenomena in polymetallic complex ores and the lack of associated research on complex ores and their constituent minerals, an investigation was conducted based on the motion theory of grinding media and the principles of selective grinding. The grinding characteristics were elucidated using metrics such as the breakage rate, grinding speed, and the t10 parameter of the ground product. The relationship between the grinding characteristics of polymetallic complex ores and their component mineral, including pyrrhotite, sphalerite, and quartz, under throw grinding conditions was investigated. The results show that during dropping state, sphalerite enhances the ore comminution effect, indicating that the presence of sphalerite plays a positive role in ore crushing, whereas pyrrhotite and quartz diminish the ore comminution effect, meaning their presence exerts a negative influence on ore crushing. The particle size characteristics of the grinding products of different constituent minerals all affect the particle size characteristics of the ore grinding products, with sphalerite showing a more significant impact on the ore's grinding characteristics. The grinding rate of both the ore and its constituent minerals exponentially decreases with prolonged grinding time, reaching a threshold when the grinding time reaches 4 minutes, where the rate of decrease rapidly slows. These findings can provide theoretical guidance for subsequent research on the optimization and control of grinding polymetallic complex ores under throw grinding. [ABSTRACT FROM AUTHOR]

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Abstract This study examined the electrodissolution mechanism of five impure sphalerite samples, which differ significantly in purity levels, along with their partially oxidized counterparts in a 0.5 M H2SO4. Partially oxidized samples were prepared through an incomplete leaching of sphalerite using H2SO4 with Fe2(SO4)3.H2O as an oxidizing agent. The original sphalerite samples and the partially oxidized samples were referred to as SP and POS samples, respectively. Analyses using XRD, SEM, Raman spectroscopy, and electrochemical techniques suggested presence of elemental sulfur and a metal-deficient layer on the surface of the POS samples. Cyclic voltammetry revealed that the sample with the highest iron content exhibited the highest electrochemical response, while the sphalerite with the highest lead concentration had the lowest activity. Electrochemical impedance spectroscopy (EIS) studies showed that impedance values were higher in the POS samples compared to the PS samples, indicating a correlation within the passivation phenomenon. In conclusion, these findings suggested that the sphalerite dissolution process is primarily controlled by charge transfer and kinetic polarization. This understanding can lead to the development of more selective and sustainable extraction methods and improving the overall economic viability of zinc hydrometallurgical operations.

A unique Mn-, Cd-bearing sphalerite from quartz-calcite veins in the coal-bearing series (Visean C1v) marine sediments in a 50 km segment of the middle course of the Silova-Yakha River in the Arctic zone of the European part of Russia (Pai-Khoi Ridge) has been studied. The veins have a conformable and cross-cutting occurrence in two types of rocks: gray limestones and black siliceous-carbonaceous shales, the area is known as the Goniatite occurrence. The sulfide content in vein samples ranges from 0.1 to 2 vol.%. The chemical composition of 27 monomineral samples of Mn-, Cd-bearing sphalerites was studied, 82 points were analyzed. Correlations between typomorphic elements-impurities were revealed and correlation matrix was constructed. Cu, V, Ga, In, Sn, As, Sb, Bi, Pb, Tl, Se, Ag, Au, Ni are positively correlated with each other; Cd, Mn and Ge are negatively correlated with each other. The hydrothermal fluid involved in crystallization of sphalerite is characterized by low temperature (164-211 °С) and average salinity of 5-6 wt.% eq. NaCl. An updated “portrait” of typomorphic features (composition and properties) of sphalerite of the Pai-Khoi province was obtained. The features allowing to determine the type of impurity entering the sphalerite structure – in the form of isomorphic impurity or in the form of microinclusions of paragenetic association minerals – have been established. Submicron inclusions of sulvanite and colusite, invisible by other methods, were detected in sphalerite (by LA-ICP-MS method).The cathodoluminescence data of sphalerite from the Pai-Khoi province were typified. In contrast to other provinces, ZnS crystals here are characterized by almost complete absence of isomorphic iron. This allowed us to study pure isomorphism schemes of ZnS↔MnS, ZnS↔CdS, namely cathodoluminescence and other types of luminescence. The presence of a rare wurtzite-4H polytype in assemblage with sphalerite was revealed. High contents of strategic metals Cd, Ga, In, Ge in the ZnS matrix, as well as sulvanite (V, Cu) in a single paragenesis were found. A serious reassessment of the potential for industrial use of this mineralization will be required.

This study constructed a synergistic homo-/heterojunction zinc blende/wurtzite cadmium sulfide/phosphorus-doped polymeric C 3 N 5 (ZB/WZ CS/PCN). It was found that manipulating Cd/S precursor ratio with Na 2 S as the S precursor can effectively control the growth of high-energy facets. Concurrently, the presence of P -doping in PCN can adequately tune the optical properties of CN through the presence of P –C/P–N/P N linkage within the CN heterocyclic ring. Owing to the intimate heterojunction which boosted the carrier transfer between CS and PCN, the optimal CS/PCN 10% produced 3840.5 μmol g−1 h−1 of hydrogen with prolonged stability (>56 h), giving rise to the intimate heterojunction and robustness. As a proof-of-concept, CS/PCN 10% was also deposited onto a 3D printed substrate obtained by fused deposition modeling (FDM), offering clear advantages for reusability of light-induced photocatalytic applications. Overall, this work provides insights into the universal application of CS/PCN photocatalysts in future scale-up opportunities of photocatalytic-based systems. [Display omitted] • Facet-engineered zinc-blende and wurtzite CdS by regulating Cd/S precursor ratio. • Synergistic P –N/P N bonding in P -doped C 3 N 5 and ZB/WZ CdS ameliorates the properties. • Photocatalyst reusability and recyclability by fused deposition modeling 3D printer. • ZB/WZ CS/PCN 10% with long term stability (>56 h) and AQY of 1.4% at 420 nm. • Multifarious application in HER, H 2 O 2 , CO 2 RR and fine chemical synthesis. [ABSTRACT FROM AUTHOR]

Process mineralogy was applied to design the process circuit of magnetite tailings containing copper, lead and zinc from Marcona Iron Ore Mine. Mineralogy parameters, such as mineral composition, occurrence, and grain size distribution of the main minerals, were investigated in detail. The results showed that the main valuable elements including 41.40 wt.% iron, 0.064 wt.% copper, 0.38 wt.% lead, and 0.96 wt.% zinc, were primarily in the occurrence of magnetite, chalcopyrite, galena, and sphalerite, respectively. In addition, complex interlocking relationships were observed among the copper-zinc-lead minerals. Therefore, a fine grinding process was required for mineral liberation, followed by magnetic separation for magnetite collection. Iso-floatability flotation process was further applied to the magnetic tailings, achieving a copper grade of 28.37 wt.% and a recovery of 25.11% in the copper concentrates. Subsequently, zinc and lead grades of 49.04% wt.% and 8.06% wt.% were obtained in the zinc-lead concentrates, with a recovery of 51.72% and 25.21%, respectively. Therefore, this study provides an available separation of copper-zinc-lead minerals from iron tailings at Marcona Iron Ore Mine based on process mineralogy, thereby giving a prior diagnosis strategy to increase the utilization efficiency of iron tailings. [ABSTRACT FROM AUTHOR]

The depression mechanism of sulfite ions on sphalerite and Pb2+ activated sphalerite in the flotation separation of galena from sphalerite still lacked in-depth insight. Therefore, the depression mechanism of sulfite ions on sphalerite and Pb2+ activated sphalerite in the flotation separation of galena from sphalerite was further systematically investigated with experiments and density functional theory (DFT) calculations. The X-ray photoelectric spectroscopy (XPS) results, DFT calculation results, and frontier molecular orbital analysis indicated that sulfite ions were difficult to be adsorbed on sphalerite surface, suggesting that sulfite ions achieved depression effects on sphalerite through other non-adsorption mechanisms. First, the oxygen content in the surface of sphalerite treated with sulfite ions increased, which enhanced the hydrophilicity of the sphalerite and further increased the difference in hydrophilicity between sphalerite and galena. Then, sulfite ions were chelated with lead ions to form PbSO3 in solution. The hydrophilic PbSO3 was more easily adsorbed on sphalerite than galena. The interaction between sulfite ions and lead ions could effectively inhibit the activation of sphalerite. In addition, the UV spectrum showed that after adding sulfite ions, the peak of perxanthate in the sphalerite treated xanthate solution was significantly stronger than that in the galena with xanthate solution, indicating that xanthate interacted more readily with sulfite ions and oxygen molecules within the sphalerite system, leading to the formation of perxanthate. However, sulfite ions hardly depressed the flotation of galena and could promote the flotation of galena to some extent. This study deepened the understanding of the depression mechanism of sulfite ions on sphalerite and Pb2+ activated sphalerite. [ABSTRACT FROM AUTHOR]

Within the framework of the macroscopic dielectric continuum model, the dispersive spectra of polar optical phonon modes of III-nitride based nanostructures with different inner and outer dielectric media are investigated in this paper. The dielectric and quantum size effects on the dispersive frequencies of phonon modes are focused and emphasized. In the case of GaN quantum rings (QRs), we found that the dielectric constant of the inner/outer medium could significantly influence the dispersive spectra of the surface optical (SO) phonon mode as the high/low-frequency SO phonon modes are mainly localized at the inner/outer surface of QRs, respectively. Moreover, such effects associated with different crystallographic structures of GaN, i.e., the wurtzite (WZ) and zinc blende (ZB) crystal structures, are also studied in detail, showing the different degenerating behavior and electron–phonon coupling strength. The results obtained in this study provide a beneficial opportunity to independently adjust dispersive spectra of the two branches of SO modes in GaN nanostructures; thus, it could be used to design and develop phonon-based detectors and sensors. [ABSTRACT FROM AUTHOR]

Based on fluorescence spectrum analysis and chemical multi-element analysis, through the process mineralogy study of a refractory lead-zinc mine in Hebei, the mineral composition, structure, main mineral embedding characteristics of the ore and the occurrence state of lead-zinc were found out. The results show that the lead content in the ore is 1.07%, and the lead minerals mainly exist in galena, accounting for 85.85%. The content of zinc is 2.08%. Zinc minerals mainly exist in sphalerite, accounting for 66.06%, and zinc oxide ore accounts for 22.43%, Galena is mainly embedded in contact with sphalerite and pyrite and metasomatized sphalerite and pyrite. The contact boundary is uneven, in harbor shape, sawtooth shape, nibbling shape, etc., with strong local metasomatism. Sphalerite is mainly in irregular heteromorphic grain structure, and a small amount is embedded in vein structure, which is distributed in disseminated shape in the ore. Through analysis, the embedded particle size of lead minerals in the raw ore is too fine and the continuous relationship with zinc flash minerals is complex, resulting in high zinc content in lead concentrate, high zinc oxidation rate, high zinc content in tailings and low zinc recovery rate.

In this paper, we present a machine learning-based approach that leverages Long Short-Term Memory (LSTM) networks combined with a sliding window technique for feature extraction, aimed at accurately predicting point defect percentages in semiconductor materials based on simulated X-ray Diffraction (XRD) data. The model was initially trained on silicon-simulated XRD data with defect percentages ranging from 1 to 5%, enabling it to predict defect percentages from 0 to 10% in silicon and other semiconductor materials, including AlAs, CdS, GaAs, Ge, and ZnS. Through extensive experimentation, we explored different sequence lengths and LSTM units, identifying the optimal configuration as a sequence length of 3501 and 4500 units, which yielded the best results. The model's mean absolute error at 4500 units was 0.021, the lowest among the LSTM configurations tested. The sliding window technique plays a crucial role in capturing temporal dependencies within the XRD data, allowing the model to generalize to other semiconductor materials. Additionally, we observed that increasing defect percentages consistently led to a rise in background intensity. We further examined the relationship between crystal structure and defect precentage predictions, uncovering consistent trends for materials with Diamond Cubic and Zinc Blende structures. This LSTM-based method offers a novel approach to predicting defect percentages using simulated XRD patterns of materials. [ABSTRACT FROM AUTHOR]

Determining the association of Pb–Zn(-Ag) mineralization with granite is crucial for understanding metallogeny and identifying exploration targets. The genesis of Pb–Zn-Ag-Sb deposits and their genetic association with Sb(-Au) deposits and granite-associated Sn-W deposits in the Tethys Himalaya of southern Tibet, China, remains controversial. Our comprehensive study of in situ element compositions and sulfur isotopes of sulfides, together with in situ quartz oxygen isotopes for the Zhaxikang Pb–Zn-Ag-Sb deposit, sheds light on this issue. LA-ICP-MS analyses of early sulfides in manganosiderite veins, coupled with C-O isotopes of manganosiderite, indicate that the early fluids were enriched in Pb, Zn, Ag, Sb, Sn, and Cu, originating from magmatic fluids mixing with meteoric water. The early formed sulfides underwent fluid-mediated remobilization and dissolution, releasing many metallic elements (e.g., Pb, Zn, and Ag) into later As-Sb-rich fluids. These elements reprecipitated as Fe-poor sphalerite, As-rich pyrite, and abundant Sb-Pb sulfosalts with minor Ag-bearing minerals. Oxygen isotopes of quartz indicate that the later fluids were derived from pulsed releases of magmatic fluids mixing with meteoric water. In situ sulfur isotopes of three generations of pyrite indicate that early Pb–Zn(-Ag) sulfide precipitation was linked to magmatic sulfur, whereas precipitation of the later sulfosalts and stibnite involved external sulfur with relatively lower sulfur isotopes compared with early mineralization. We argue that Pb–Zn-Ag-Sb deposits in the Tethys Himalaya resulted from two distinct mineralization pulses. The early Pb–Zn(-Ag) mineralization was associated with crustal magmatic rocks (e.g., leucogranite), followed by the overprinting of later Sb-rich magmatic fluids. Notably, the later magmatic fluids responsible for Zhaxikang Pb–Zn-Ag-Sb mineralization were also associated with the regional Sb(-Au) deposits in the Tethys Himalaya. [ABSTRACT FROM AUTHOR]

The Lautenthal sphalerite-galena vein deposit is part of the world-class Upper Harz Pb-Zn-Ag district in the Harz uplift block of the Paleozoic Variscan fold belt in Germany. Its sphalerite-dominated mineral association was studied using bulk-ore chemistry, electron probe microanalysis, and laser ablation-ICP-mass spectrometry. Gallium and locally In are the main high-tech-relevant trace elements hosted by sphalerite, with up to 150 ppm Ga and up to 380 ppm In in hand-picked sphalerite samples (mean In/Zn, 0.70 × 10−3). Ore concentrates (≤ 50 kg) contain up to 65 ppm Ga and up to 109 ppm In (mean In/Zn, 0.36 × 10−3). Accessory Fe-Co-rich gersdorffite-1 occurs in the earlier quartz-sulfide ore stage and Sb-rich gersdorffite-2 in the later carbonate-sulfide stage. Enrichment patterns of In are either defined by overprinting textures in the Fe-richer sphalerite-1 of the earlier stage, or relate to primary growth zoning in Fe-poor sphalerite-2 of the later stage. Using the sphalerite geothermometer GGIMFis, formation temperatures (median) of sphalerite-1 were estimated at ~ 230 °C for the Lautenthal orebody and at ~ 175 °C for the Bromberg orebody, which may indicate lateral T-zonation for the earlier ore stage. Sphalerite-2 data indicate formation temperatures of ~ 185 °C (median). Copper-bearing brines of the carbonate-sulfide stage with assumed temperatures of ~ 250 °C initiated replacement of In-poor sphalerite-1 by chalcopyrite and remobilization of Zn and trace elements. Indium-rich sphalerite-2 occurs associated with calcite and fine-grained galena. A direct spatial or temporal link of ore formation to a magmatic-hydrothermal system is unlikely, which contrasts to In-rich epithermal and tin-polymetallic vein deposits worldwide. [ABSTRACT FROM AUTHOR]

The coexistence of numerous Mississippi-Valley-type (MVT) Zn–Pb deposits and (paleo) oil/gas reservoirs in the world suggests a close genetic relationship between mineralization and hydrocarbon accumulation. Xuequ–Shandouya middle MVT Zn–Pb deposits are mainly hosted in the Lower Cambrian Maidiping Member siliceous dolostone on the southwestern margin of the Yangtze Block, accompanied by large amount of bitumen in the orebodies. Therefore, this type of Zn–Pb deposit is a natural laboratory for studying the relationship between the mineralization and the accumulation of paleo-oil/gas reservoirs. The deposit is characterized by spheroidal and concentric banded sphalerite. In situ sulfur isotope studies are carried out to determine the sulfur sources, sulfate reduction mechanisms, and role of hydrocarbons in the zinc–lead mineralization process. According to the mineral paragenesis and relative temporal relationship, two mineralization stages (1 and 2) are identified. An in situ sulfur isotope analysis of spheroidal and concentric banded sphalerite particles from Stage 2 shows that there are the two following types of sulfur isotopes in the sphalerite: one with relatively invariable δ34S values in the core (+8.31 to +9.30‰), and the other with a gradual increase from the core margin (core) to the rim (+0.39 to +16.18‰). These two types reflect that they may have formed in different times, with first type forming in the early period of Stage 2, while the second type was formed in the late period of Stage 2. The sulfur isotopic data suggest the sulfur source of evaporated sulfate minerals and multiple formation mechanisms for reduced sulfur (H2S). In the early period of Stage 2 mineralization, the sulfate reduction mechanism is mainly a mixture of bacterial sulfate reduction (BSR) and/or thermochemical sulfate reduction (TSR), while a very small amount may come from the thermal decomposition of organic compounds (DOCs). In the late period of Stage 2, TSR is dominant, and the gradual increase in the δ34S value may be related to Rayleigh fractionation. The oil/gasreservoir not only acts as a reducing agent to provide the required hydrogen sulfide for zinc–lead mineralization through TSR or BSR, but also provides reduced sulfur for mineralization through the thermal decomposition of organic compounds directly. [ABSTRACT FROM AUTHOR]

Detrital zircons from the Jack Hills are the dominant source of Hadean (pre-4000 Ma) terrestrial material available for study today. Values of δ18O in many of these zircons (6.0 to 7.5‰) are above the mantle-equilibrated value. For two decades, these mildly elevated values have been the primary evidence that protoliths of the zircon-forming magmas interacted at low temperature with liquid water before burial and melting, implying that the surface of Earth cooled quickly after core and Moon formation and that habitable conditions for life existed within 250 Myr of the formation of Earth, over 800 Myr before the oldest generally accepted microfossils. These conclusions are based on oxygen isotope analyses of zircon domains with well-defined growth zoning and nearly concordant U-Pb ages within zircon grains with low magnetic susceptibility, which are further inferred to be unaltered by various tests. However, no studies of Jack Hills zircons have directly correlated oxygen isotope ratios and radiation damage, which facilitates alteration in zircon. Several previous studies have selected zircons that show radiation-damaged, discordant, and/or hydrous domains and have shown that such altered material is not reliable as a record of igneous composition. In contrast, this study targeted zircons that are interpreted as not altered and demonstrates the importance of testing zircons for radiation damage and alteration as part of any geochemical study, regardless of age. This study expands on existing data and presents the first comprehensive evaluation of δ18O, OH/O, CL imaging, U-Pb concordance, and radiation-damage state within Jack Hills zircons. A total of 115 Hadean zircon grains in this study have water contents similar to nominally anhydrous standard reference zircons and are interpreted as pristine. Raman band broadening correlated with δ18O reveals low levels of radiation damage, indicating significant annealing. The present-day effective doses (Deff) are uniformly less than the first percolation point [dose where damage domains, that are isolated at lower damage state, overlap to form a continuous pathway through the crystal, ~2 × 1015 α-decays/mg (Ewing et al. 2003)] and most zircons have Deff <1 × 1015 α-decays/mg. Modeling of representative α-recoil damage and annealing histories indicates that most zircons in this study have remained below the Deff of the first percolation point throughout their history. The δ18O values for these primary zircons include many that are higher than would be equilibrated with the mantle at magmatic temperatures and average 6.32 ± 1.3‰ in the Hadean and 6.26 ± 1.6‰ in the Archean. There is no correlation in our suite of unaltered Hadean zircons between δ18O and OH/O, Deff, age, or U-Pb age concordance. These carefully documented Hadean-age zircons have low amounts of radiation damage in water-poor domains sampled by δ18O analysis. The mildly elevated δ18O values are a primary magmatic geochemical signature. These results strengthen the conclusion that mildly elevated-δ18O magmas existed during the Hadean, supporting the hypothesis that oceans and a habitable Earth existed before 4300 Ma. [ABSTRACT FROM AUTHOR]

The flotation characteristics of chalcopyrite, galena and sphalerite in the system with dextrin, sodium humate (HA-Na), cationic guar gum (CGG) and DP115 (modified polyacrylamide) as inhibitors and Z-200 as collector were investigated. The results showed that compared with the traditional system of adding macromolecular organic inhibitor first and then adding Z-200 collector, the three sulfide minerals showed different flotation behaviors in the system of adding Z-200 first and then adding macromolecular organic inhibitor. Chalcopyrite was basically not affected by dextrin, while dextrin more strongly inhibits galena, sphalerite was slightly activated by lower dosage of dextrin and was equivalent to that of adding dextrin first and then adding Z-200, and higher dosage of dextrin slightly enhanced the inhibition of sphalerite. HA-Na weakened the inhibition of three sulfide minerals. The inhibition of CGG on sphalerite, especially chalcopyrite, was enhanced, while the inhibition of galena was basically equivalent to that of CGG when added first. Chalcopyrite was basically not affected by DP115, and the lower amount of DP115 more strongly inhibited galena and sphalerite, while the inhibition of higher amount of DP115 on galena and sphalerite was basically the same as that of adding DP115 first and then Z-200. The research results can provide reference for the selection of organic macromolecular inhibitors and the improvement of flotation separation efficiency when Z-200 was used as collector in the flotation separation of copper-lead-zinc sulfide ore. [ABSTRACT FROM AUTHOR]

The main metals contents in a platinum group polymetallic ore in South Africa are Pt 1.923 g/t, Pd 0.986 g/t, Au 0.276 g/t, Rh 0.113 g/t, Ru 0.316 g/t, Ir 0.047 g/t, Cu 0.071% and Ni 0.180%. The content of Cr2O3 is only 0.58%, and the contents of main gangue components SiO2, MgO, Al2O3 and CaO are 52.59%, 22.4%, 5.06% and 4.27% respectively. The total sulfide content in the ore is 0.94%, presenting mainly in pyrrhotite, nickelpyrite, chalcopyrite, followed by pyrite, trace chalcocite, sphalerite, and so on. The total amount of silicate minerals is 97.91% mainly bronze- pyroxene, followed by secondary diopside, a small amount of plagioclase, plagiozossite, quadrigalite, phlogopite, chlorite, and so on. Platinum group metals are mainly found in sulfide platinite, arsenic platinite, natural platinum, sulfide nickel palladium platinite, natural gold, silver gold and other minerals, while copper and nickel metals are mainly found in chalcopyrite and nickel pyrite. Under the condition of grinding tineness of -74 µm accounting for 55% the liberation degree of PPD rhodium minerals is 96.6% the proportion of exposed gold and sulfide wrapped gold are 69.21% and 20.67% respectively. In order to comprehensively recover the platinum group metal and valuable elements such as copper and nickel, beneficiation experiments were carried out. The results showed that under the process of "one roughing, two scavengings and three cleanings", with sodium carbonate, CMC and copper sulfate as regulators, amyl xanthoxanthate as collector, and terpineol oil as frother, the concentrate obtained contained Pt 57.562 g/t, Pd 34.836 g/t, Au 5. 201 g/t, Rh 3. 266 g/t, Cu 2.270% and Ni 3.830%. The metal recoveries were Pt 90.57%, Pb 93.80%, Au 51.63%, Rh 88.13%, Cu 87.03% and Ni 63.16%. The main impurities in the concentrate were SiO2 42.28%, MgO 19.82%, Al2O3 1.68%, CaO 1.89% and Fe 18.79% respectively. This study can provide technical reference for the exploitation and utilization of similar mineral resources. [ABSTRACT FROM AUTHOR]

The Kalateh Dasht deposit is situated in the northern part of the Central Iran structural zone, northeast of the Toroud-Chah Shirin magmatic arc. The Cu-Au mineralization is hosted by diorite porphyry subvolcanic rocks with a post-Eocene age. The mineralization occurs in the form of hydrothermal breccia and vein-veinlet along a fault zone with an approximately N30E extension and vertical dip. Several mineralized veins consisting of pyrite, chalcopyrite, sphalerite, bornite, galena, barite, hematite, chalcocite, covellite, malachite, and chrysocolla are observed parallel to each other in this fault zone. The gangue minerals include comb quartz, crustiform, and a small amount of amethyst as veins and blades. SEM data indicate the presence of gold within sphalerite. The porphyritic diorite host rocks have been significantly altered due to the action of hydrothermal fluids, resulting in sericitic, siliceous, and propylitic alteration (chlorite, epidote, and calcite), particularly at the margins of mineralized veins. The fluid inclusions in calcite and barite host minerals reveal that homogenization temfaatures range between 143.2 and 213.1ºC and salinity varies between 3.06 and 7.73 wt.% NaCl eq. In close proximity to this ore deposit, an argillic alteration zone and other mineralization systems in this region increase the likelihood of a porphyry system at greater depth. IntroductionDespite the abundance of mineralization in the Toroud-Chah Shirin magmatic arc (TCSMA), certain deposits, such as the polymetallic Kalateh Dasht deposit with its post Eocene diorite porphyry host rock, have not yet been thoroughly investigated in terms of their geology, mineralogy, and genesis. The studied area is located in the northern part of the Central Iran (CI) zone and is a small part of the 1:100,000 geological map of Moaleman (Eshraghi and Jalali, 2006). This mining area is situated northeast of the TCSMA and east of the Chah-Musa copfa deposit - 13 km north of the Toroud village (Fig. 1). This article comprehensively analyzes the field characteristics, mineralogy, mineralography, and fluid inclusion data of the Kalateh Dasht deposit. Given the likely hydrothermal origin of the deposit, which can be linked to the Eocene magmatic activity and controlled by fault structures, the investigation of these deposits assumes great significance in exploring epithermal mineralization within the Toroud-Chah Shirin magmatic arc. Material and methodsFollowing a thorough field investigation, a total of 50 samples were collected from the exploratory trenches of Kalateh Dasht to conduct precise mineralogy, mineralography, and hydrothermal alteration studies. These samples consist of ore minerals and quartz-calcite-(barite) veins containing sulfides of both base and precious metals. The locations of these collected samples are indicated in Figure 2. Subsequently, thin (10 samples), polished (13 samples), and thin-polished (25 samples) sections were prepared at both Shahrood and Clausthal University of Technology in Germany. These sections were then examined using an Olympus polarizing microscope. To investigate the physicochemical profaties of the mineralized fluid, two double-polished cross-section samples of barite-calcite veins were prepared and analyzed. Temfaature and salinity measurements of fluid inclusions were carried out at the Economic Geology Laboratory of Shahrood University of Technology, using the Linkam MDSG600 model heating-freezing stage. Additionally, the Field Emission Scanning Electron Microscope (FE-SEM) model Sigma 300-HV, at Shahrood University of Technology, was utilized to identify specific minerals. Results According to the data presented in the research, mineralization primarily occurs along a fault zone with an approximately N30E trend and vertical dip. In the field, various structures including hydrothermal breccia, banded, and vein structures can be observed. Within the fault zone in the trench, multiple parallel mineralized veins are present. These veins host minerals such as pyrite, chalcopyrite, sphalerite, bornite, galena, and hematite, accompanied by gangue minerals like comb-style, crustiform, amethyst, and barite, with variable thicknesses ranging from 3 to 5 cm. SEM studies have revealed the presence of gold within the ores. The porphyritic diorite host rocks have undergone significant alteration due to the infiltration of hydrothermal fluids. Sericite, silicic, and propylitic (chlorite + epidote + calcite) alteration zones have been identified along the margins of the mineralized veins, exhibiting high intensity. Fluid inclusion studies conducted on quartz and barite minerals indicate homogenization temfaatures ranging between 143.2 and 213.1°C. The degree of salinity falls within the range of 3.06 to 7.73 wt.% NaCl eq. The mineralogical characteristics of the Kalateh Dasht deposit are comparable to base and precious metal intermediate sulfidation (IS) epithermal deposits. Discussions The field studies, mineralogy, structure and texture, alteration patterns, and fluid inclusion analysis in the Kalateh Dasht deposit show mineralization occuring in subvolcanic rocks composed of porphyry diorite, taking the form of vein-veinlet, hydrothermal breccia, open space-filling, and disseminated. The deposition of ore minerals occurred during two stages: the deposition of primary sulfide minerals (such as pyrite, chalcopyrite, galena, sphalerite, bornite, and hematite) in quartz veins and the formation of secondary minerals (such as covellite, digenite, cuprite, malachite, azurite, and chrysocolla). The formation of mineral veins is associated with a fault zone, as well as other joints and fractures in the area. The study of fluid inclusions trapped in calcite and barite minerals reveals that the homogenization temfaature ranges from 143.2 to 213.1 ºC, and the salinity ranges from 3.06 to 7.73 wt.% NaCl eq. Such a thorough analysis of this type of mineralization can be of great value in identifying similar occurrences in the TCSMA. Light-colored sphalerite has been observed at the eastern end of the Kalateh Dasht deposit and close to a zone exhibiting argillic alteration. The presence of light-colored sphalerite, which indicates a low iron content, serves as an additional indicator of epithermal systems with moderate sulfidation. This observation is consistent with the occurrence of relatively oxidized fluids and the formation of sphalerite at the interface of two IS and HS systems (Wang et al., 2019). Strong spatio-temporal-genetic associations with porphyry molybdenum mineralization have been documented in the metallogenic belts of numerous IS systems. Consequently, the proximity of the Kalateh Dasht IS system to an argillic zone may indicate the presence of a profound porphyry system and offer the potential the discovery of similar deposits. [ABSTRACT FROM AUTHOR]

Aiming at the high recovery value of silver concentrate and insufficient of existing treatment technology, applying the germanium-containing silver concentrate produced by zinc hydrometallurgy as research object, a process route of concentrated sulfuric acid curing and oxygen pressure acid leaching was put forward, focusing on the principle of the process, leaching behavior of Zn, Cu and Ge in the process of curing and oxygen pressure acid leaching of germanium containing silver concentrate and phase evolution in the leaching residue. The results indicate that low valence metal sulfide in germanium containing silver concentrate and the residual organic flotation chemicals on the concentrate surface can be oxidized and decomposed by pretreatment with concentrated sulfuric acid. Under the condition of high temperature oxidation and assisted leaching by Fe3+/Fe2+ variable ion pairs, the phase composition of the germanium- containing silver concentrate mainly evolves from dominated by iron sphalerite, sphalerite, gynopyrite and cuprous chloride to dominated by elemental sulfur, lead sulfate and ferrosite (MeFe3(SO4)2(OH)6 > Me: 1/2Pb, Na, K) in leaching residue Under the optimum oxygen pressure acid leaching conditions including reaction temperature of 150 °C, initial acidity of 150 g/L, reaction time of 180 min, partial oxygen pressure of 0.6 MPa, and liquid-solid ratk> of 7 mL/g, the leaching rate of Zn, Cu and Ge is 95.34%, 98.47% and 84.35%, respectively, and the enrichment of lead and sliver reaches 3.19% and 7 074 g/t, respectively, which reaiizes the deep leaching of Zn, Cu, and Ge, and efficient enrichment of Pb and Ag. [ABSTRACT FROM AUTHOR]

Aiming at the problems of low oxygen utilization rate and slow dissolution of sphalerite in the pressure leaching process of zinc concentrate, the strong oxidizability of Fe3+ in zinc leaching residue and the oxygen transport efficiency of Fe2+/Fe3+ redox ion pair were used to improve the efficient oxidation of S2- in sphalerite and the utilization rate of O2, so as to realize the synergistic enhanced leaching of zinc concentrate and zinc leaching residue. The results show that Fe3+ can improve the solubility of oxygen, and the back-and-forth valence behavior of Fe2+/Fe3+ accelerates the oxidative dissolution of sphalerite (ZnS) in the leaching system, and the leaching rate and leaching efficiency of zinc are significantly improved. Under the optimal process conditions of initial sulphuric acid concentration of 95 g/L, oxygen partial pressure of 0.8 MPa, temperature of 160 °C, reaction time of 120 min, and pH value of 3, and the addition of 6.1 g/L Fe3+ in the form of zinc leaching residue results in a high leaching rate of 98.60% of zinc, and 92.47% of iron is precipitated into the residue. The synergic Caching of zinc concentrate and zinc leaching residue is controHed by external diffusion with apparent activation energy of 15.61 kj/mol. The kinetic equation of synergc Caching process Is as follows; 1-(1-a)1/3=4.78X 10-3 X {[exp(-15610/8.314T)] Xc(H2SO4)1,21 XP(O2)0.33 Xc(Fe3+)0.43Xt} . [ABSTRACT FROM AUTHOR]

High-entropy carbides with tunable crystallization and growth have been demonstrated using single-source precursor derived ceramic route. The in situ nanocrystallization of high-entropy carbide phases, (Ta 0.2 W 0.2 V 0.2 Mo 0.2 Nb 0.2)Si δ C and (Ta 0.167 W 0.167 V 0.167 Mo 0.167 Nb 0.167 Si 0.167)C in amorphous Si-based ceramic matrices was achieved by using polysiloxanes and polycarbosilanes as polymer precursors respectively. The results exemplify a prominent role of the architectures of the polymeric precursors in controlling the structural features of these ceramics at various length scales. In particular, it was observed that high-entropy carbides with rock salt and zinc blende crystal structures were formed when polysiloxanes and polycarbosilanes with different backbone structure were used as polymeric precursors respectively. This is attributed to the thermodynamics of nucleation of the carbidic phases in these nanocomposites. Furthermore, the precursor architecture that dictates free carbon content, influenced nanostructural features and porosity in the material. Therefore, engineering such compositionally complex phases is feasible by selecting suitable polymeric precursors. • Precursor architecture influenced the crystal structure of high-entropy carbides. • Crystal structure dependent on earliest nucleated carbidic phase. • Free carbon played a key role in controlling crystallite size and porosity. [ABSTRACT FROM AUTHOR]

A calc–alkaline dioritic–andesitic–dacitic intrusive–volcanic complex of Early Oligocene (30 Ma) age and its Mesozoic sedimentary basement at Recsk host a well-preserved porphyry–skarn–polymetallic carbonate-replacement–epithermal mineral system. The unique occurrence offers an exceptional possibility to study these related mineralization types at a single locality. This study presents the textural–paragenetic, compositional characteristics, and systematics of sulfide mineral assemblages for the porphyry, skarn, and carbonate-replacement ore types, which are currently situated at a depth of 500–1200 m below the present surface. Detailed petrography combined with EPMA analyses of molybdenite, galena, sphalerite, tetrahedrite-group minerals and Bi-bearing sulfosalts allows for the establishment of characteristic mineral and chemical fingerprints for each mineralization type. Rhenium concentration in molybdenite, occurring as rare disseminations and quartz–carbonate veinlets in altered host rocks in all three mineralization types, shows a decreasing trend towards the more distal mineralization types. High Re contents ( x ¯ = 1.04 wt.%, max. up to 4.47 wt%) are typical for molybdenite from the porphyry mineralization, but Re is not homogeneously distributed, neither within individual molybdenite crystals nor on a mineralization scale. Copper and Se show opposite behavior in molybdenite, both becoming enriched in the more distal mineralization types. Silver, Bi, and Se concentrations increase in galena and tetrahedrite-group minerals, both towards the country rocks, making them the best candidates for vectoring within the whole hydrothermal system. For tetrahedrite-group minerals, Ag, Bi, Se, together with Sb and Zn, are the suitable elements for fingerprinting; all these are significantly enriched in the distal carbonate-replacement mineralization compared to the other, more proximal ore types. Additionally, further trends can be traced within the composition of sulfosalts. Lead-bearing Bi sulfosalts preferentially occur in the polymetallic carbonate-replacement veins, while being under-represented in the skarn and porphyry mineralization. Porphyry mineralization hosts Cu-bearing Bi sulfosalts dominantly, while skarn is characterized by Bi-dominated sulfosalts. Sphalerite, although present in all mineralization types, cannot be used for fingerprinting, vectoring, or thermobarometry based on EPMA measurements only. Trace element contents of sphalerite are low, often below the detection limits of the analyses. This is further complicated by the intense "chalcopyrite disease" occurring throughout the distal mineralization types. All the above-listed major, minor, and trace element ore mineral characteristics enable the characterization of the Recsk ores by mineral geochemical fingerprints, providing a possible vectoring tool in porphyry Cu–(Mo)–Au-mineralized systems. [ABSTRACT FROM AUTHOR]

The concealed Molai Zn-Pb±(Ag,Ge) stratiform deposit in southeastern Peloponnese is hosted in Triassic intermediate tuffs, ignimbrites and subaerial andesitic flows. The host rocks display trace element signatures of a Supra-Subduction Zone (SSZ) setting. Three ore-forming stages are recognized, with stages I and II related to formation of the epigenetic, stratiform, massive-to-semi-massive ore and a late stage III associated with vein-type mineralization. The O and D isotope geochemistry of gangue chlorite and epidote reveal mixing with fresh meteoric water during the weaning stages of the hydrothermal activity of the late stage II due to uplifting of the hydrothermal system. Sphalerite is the major ore phase, with three different varieties formed during stages I (Sp-I) and II (Sp-II and Sp-III). All sphalerite varieties coexist, depicting gradual change in the chemistry of the ore-forming fluids. Molai ores are characterized by elevated Ag and Ge contents. Tetrahedrite is the major Ag carrier, while among the three sphalerite varieties, early Sp-I comprises the highest Ge contents. The Molai Zn-Pb±(Ag,Ge) deposit is characterized by intermediate features between bimodal felsic massive sulfides and subaerial epithermal systems based on the shallow formation depth, the presence of hydraulic breccias associated with phase separation, the ore formation along high-angle faults, the relatively low ore-forming temperatures below 250 °C obtained from geothermometry, and the absence of the typical structure of bimodal felsic type ores. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study of the mineralogical and chemical composition of zinc and lead metallurgical slags. These slags contain numerous elements, including toxic metals, which form conglomerates or multiphase intergrowths. The phase composition of slags is one of the main factors that determine their behaviour in weathering environments, that is, their ability to release metals when exposed to atmospheric factors. In this paper, the release of elements from slags and their mobility in a hypergenic environment is determined based on the results of leachability tests and on geochemical modelling, thus assessing the environmental impact of landfilled slags. The elements released from slags in the largest quantities are zinc and lead. Zn is leached out over a long period of time. It was found that after 12 years, the concentration of Zn in the eluate exceeds by 40 times the permissible value of 200 mg/kg for hazardous waste. The degree of leaching of lead from slags as a function of time (after 12 years), despite its significant solubility in water, is much lower than the degree of leaching of zinc. The most mobile phase components of slags in the studied hypergenic environment are the lead phases (anglesite and galena) and, to a lesser extent, the zinc phases (sphalerite and willemite). Anglesite and galena in almost the entire Eh-pH range, along with admixtures of elements, decompose into ionic forms: PbCl42−, Pb2+, and PbOH+. Sphalerite in the soil and water environment (oxidizing and acidic conditions) will decompose into the mobile ionic form Zn2+. Willemite, which is resistant to weathering, will undergo similar decomposition. It can therefore be assumed that the carriers of toxic metals are primarily lead sulphides and sulphates, zinc sulphides, and, less frequently, zinc, lead, and iron oxides. [ABSTRACT FROM AUTHOR]