Sulfide Composites Research Articles

Controllable synthesis of hierarchical core-shell NiS2/CoS2@N,S-C nanospheres for lithium storage

Transition metal sulfides (TMSs) present high theoretical capacity as anode materials for Lithium-ion batteries, and structural design of TMSs is proved to be an effective strategy to acquire satisfactory electrochemical performances. Herein, the hierarchical NiS 2 /CoS 2 @N,S-C nanospheres consisting of NiS 2 /CoS 2 matrixes and N,S-codoped carbon outer layer (N,S-C) are fabricated. Additionally, NiS 2 /CoS 2 @N,S-C nanospheres with different core-shell structures appear in this study when the amount of nickle and cobalt is precisely controlled, which further confirms the different abilities of nickle and cobalt in tailoring and modulating structure. In particular, the NiS 2 /CoS 2 @N,S-C(Ni:Co=1:2) with yolk-shell property presents sufficient internal void space, which is conductive to the transport of Li + and electron. Moreover, the protective N,S-codoped carbon layer and the porous sheet arrays provide the enhanced structural stability and increased active sites. Benefitting from the unique structure, the NiS 2 /CoS 2 @N,S-C(Ni:Co=1:2) anode with binary metal sulfide composition presents good cycling performance (795 mAh g −1 at 0.2 A g −1 after 100 cycles) and rate capability (469 mAh g −1 at 5 A g −1 ). This study provides a reference for the design and preparation of novel TMSs-based materials with different morphologies in the field of energy storage. • NiS 2 /CoS 2 nanosphere encapsulated in the N,S-codoped carbon layer to synthesize the hierarchical NiS 2 /CoS 2 @N,S-C. • The regulation of core-shell structure of NiS 2 /CoS 2 nanospheres by changing the molar ratio of Ni/Co. • The N,S-codoped carbon layer improves the structural stability and conductivity of the final composites. • The NiS 2 /CoS 2 @N,S-C(Ni:Co=1:2) delivers the improved lithium storage performance than other vulcanized composites.

Mechanical performance of Continuous/Short carbon Fiber-Reinforced Poly(phenylene sulfide) composites

A method for improving the fracture resistance and mechanical strength behavior of polymer composites by incorporating short carbon fibers into continuous fiber/poly(phenylene sulfide) laminate was explored in this manuscript. This method involves the incorporation of short carbon fibers into continuous carbon fiber thermoplastic laminates, by using the hot compression molding technique. Characterization of a continuous and discontinuous carbon fiber composite material with poly(phenylene sulfide) matrix (S-CCF/PPS laminate) was performed by using tensile, V-Notched Iosipescu, combined load compression and impulse excitation tests. According to the found results for this composite material, it was observed that the tensile strength and the elastic modulus values were 41% and 48% lower than a composite reinforced only by continuous fiber, respectively. The shear strength of the mixed material was found to be 32% lower than a continuous carbon fiber composite. These results were expected since it was used a combination of 50% of continuous and 50% of short carbon fiber, in volume. However, the compression strength of the mixed composite was found to be only 11.9% lower than a laminate reinforced with solely continuous carbon fiber, showing a synergic gain in this case. In addition, the impulse excitation results show that the material mechanical properties are within the expected range, but a high dispersion of the values was observed due probably to the random nature of the discontinuous fiber. Furthermore, it was observed that the failure modes for the composite evaluated in this work are similar to those found for composites processed only with continuous reinforcements and that the models used during the simulations presented similar results to what was found experimentally.

Genesis of the giant Zijinshan epithermal Cu-Au deposit, Fujian Province, southeastern China: Cu-He-Ar isotope perspective

The giant Zijinshan high-sulfidation epithermal Cu-Au deposit is located in the Zijinshan ore field of southeastern China. A sharp boundary separates the upper Au orebodies from lower Cu orebodies at roughly 650 m below the original pit surface, below which digenite is the predominant Cu-bearing mineral. The current discussion revolves over whether the shallow Au and deep Cu mineralization are cogenetic or reflect independent ore-forming episodes, as well as whether the digenite formation is hydrothermal or supergene. In this contribution, we investigate the He-Ar isotope compositions of ore-related sulfides to decipher the source and history of ore-bearing fluids, and use the systematic variation of Cu isotope in Cu-bearing minerals to reveal the hydrothermal (hypogene and supergene) process.A gradual decrease in fluid 3He/4He and 40Ar/36Ar ratios, as well as a sharp drop in 3He/36Ar ratio, reflects the progressive dilution of a magmatic-sourced hydrothermal fluid by meteoric water. Some pyrites have 3He/4He ratios nearly identical to those of mantle fluid, indicating that the ore-forming fluids were mantle-derived with insignificant crust assimilation. The 3He/heat ratios that are higher than those of mid-oceanic ridges, indicating that the heat was transported by convection of low-temperature fluids with hydrothermal fluids rather than direct magma volatile injection. The copper isotope composition of the sulfides (δ65Cu = -3.59 to 1.33 ‰) increases with depth, which was likely caused by the release and downward transport of heavier copper isotopes near the surface. More than half (14 of 24) of these sulfides have a hypogene origin (δ65Cu = -0.05 ± 0.18 ‰), with 9 of 24 samples are likely of supergene origin. Combining with previous study, we confirm that enriched 65Cu reservoir is absent at Zijinshan.Based on the mass-balance of Cu isotopes and the spatial orebody relationship, we conclude that the leaching by meteoric water contributed to the conversion of low-grade initial hypogene Au mineralization into supergene, friable high-grade ore, resulting in the vertical zoning of Au and Cu at Zijinshan. Furthermore, the 65Cu-rich fluids produced by leaching may have lost to the groundwater, resulting in little exploration potential for 65Cu enrichment zone, while the uniform pattern of Cu isotope in the deep indicates a high exploration potential for hypogene Cu mineralization zone at depth.

A multiple sulfur record of super-large volcanic eruptions in Archaean pyrite nodules

Archaean supracrustal rocks carry a record of mass-independently fractionated S that is interpreted to be derived from UV-induced photochemical reactions in an oxygen-deficient atmosphere. Experiments with photochemical reactions of SO2 gas have provided some insight into these processes. However, reconciling experimental results with the multiple S isotopic composition of the Archaean sedimentary record has proven difficult and represents one of the outstanding issues in understanding the Archaean surface S-cycle. We present quadruple S isotope data (32S, 33S, 34S, 36S) for pyrite from Mesoarchaean carbonaceous sediments of the Dominion Group, South Africa, deposited in an acidic volcanic lake, which help reconcile observations from the Archaean sedimentary record with the results of photochemical experiments. The data, which show low Δ33S/δ34S ratios (mostly ≪ 1) and very negative Δ36S/Δ33S ratios (−4 and lower), contrast with the composition of most Archaean sedimentary sulfides and sulfates, having Δ36S/Δ33S∼−1 (the so-called ‘Archaean reference array’), but match those of modern photochemical sulfate aerosols produced in the stratosphere, following super-large volcanic eruptions, and preserved in Antarctic ice. These data are also consistent with the results of UV-irradiation experiments of SO2 gas at variable gas pressure. The S isotope composition of the Dominion Group pyrite is here interpreted to reflect the products of photolysis in a low-oxygen-level atmosphere at high SO2 pressure during large volcanic eruptions, mixed with Archaean ‘background’ (having a composition broadly similar to the Archaean reference array) S pools. It is inferred that high sedimentation rates in a terrestrial basin resulted in an instantaneously trapped input of atmospheric S during short-lasted depositional intervals, which faithfully represents transient photochemical signals in comparison with marine sedimentary records.

Origin of the Early Cambrian Huayuan carbonate-hosted Zn-Pb orefield, South China: Constraints from sulfide trace elements and sulfur isotopes

The Huayuan Zn-Pb orefield in the southeastern Yangtze Craton contains over 20 Mt Zn + Pb metal resource @ 4%, including several large, Lower Cambrian carbonate-hosted deposits classified as Mississippi Valley-Type (MVT). The source of zinc and lead and the ore-forming processes involved are still unclear. Trace elements and sulfur isotope compositions of sulfides from the large-scale Limei and Danaopo Zn-Pb deposits in the orefield favor a fluid-mixing metallogenic hypothesis. Alteration/mineralization occurred in three stages (S1-S3), forming pale-yellow sphalerite (S1: Sp1), yellow–brown sphalerite and pyrite (S2: Sp2-Py2), and galena-pyrite (S3: Gn-Py3).Syn-sedimentary fine-grained pyrite (Py1) in the Lower Cambrian Qingxudong Formation (Fm.) algal limestone has high Co, Ni, and As concentrations, whereas hydrothermal Py2 and Py3 in sulfide-calcite veins are rich in Zn and Pb, respectively. All the pyrites have low Co/Ni ratios (<2), indicating that the Fe, Co, and Ni are from a sedimentary source. Sphalerites from Limei and Danaopo are rich in Cd, Cl, and Ge but poor in Fe, Mn, and Co. They were formed under low-medium temperature (134–236 °C; determined by the concentrations of Mn, Fe, Ga, Ge, In, and Sb) and in an acidic and low-fO2 hydrothermal system, which are consistent with typical MVT ores. Lower Cambrian algal limestone (δ34SΣS = 34.3–34.4‰) contributed most sulfur to the ore sulfides (δ34S = 29.3–37.2‰). Meanwhile, the Lower Cambrian Niutitang Fm. Pb-Zn-rich black shale is likely the main ore metal source, but its limited sulfate content may not be able to provide sufficient sulfur. We propose a mixing between metal-rich brines leached from the basal Niutitang Fm. black shale with H2S-rich fluid resulting from thermochemical sulfate reduction (TSR) of the Qingxudong algal limestone formation, thus destabilizing the base metal chloride complexes and precipitating the Zn-Pb ores.

Sulfide micro-textures and in-situ compositions from the Wulong gold deposit, northeastern North China Craton: Implication for ore-forming processes

Lode gold deposits in the North China Craton (NCC) form the only known giant late Mesozoic gold province in the world’s Precambrian cratons. Understanding the ore genesis for these deposits is of great scientific and economic importance. In order to provide constraints on the ore-forming processes, this study presents a combination of micro-textures and in-situ compositions of sulfide from the Wulong gold deposit (80 t @ 5.35 g/t Au; 127–122 Ma), northeastern NCC. Five sub-generations of pyrite (Py1–Py5) are identified based on micro-textural observations and EPMA results. In-situ trace elemental concentrations show that pyrite from the stage 1 (Py1) has high Co and Ni contents but no Au (<0.02 ppm). In contrast, euhedral Py2 and porous Py3 from stage 2 exhibit much higher Au (average 3.08 ppm and 1.66 ppm), As (average 1400 ppm and 946 ppm), and Ag (average 2.81 ppm and 3.21 ppm). Anhedral Py4 from stage 3 shows lower Au (average 0.31 ppm) and As (average 337 ppm) concentrations when compared to Py3. However, Py5 from stage 3 exhibits significant increases of As (average 7102 ppm) and Au (average 5.46 ppm) again and is featured by the alternation of Co-Ni- and Au-As-rich zones. Other sulfides, including pyrrhotite, chalcopyrite, and sphalerite, are poor in Au and As. Apart from visible gold grains related to Bi-rich melts, LA-ICP-MS spot and mapping analyses reveal that invisible gold hosted in Py2 to Py5 occurs dominantly as lattice-bound solid solutions (Au+). Direct gold precipitation from anomalously As-rich auriferous fluids induced by fluid immiscibility is proposed as the dominant mechanism of invisible gold enrichment. In-situ δ34S values of Py1 to Py4 exhibit narrow ranges of 1.0 to 3.8 ‰, indicating a deep-seated magmatic sulfur source. The elevated δ34S values (2.3–6.3 ‰) of Py5 are ascribed to some wall-rock contributions during fluid-rock interaction. These findings shed new light on the link between multistage fluid immiscibility and the chemical and micro-textural fingerprints of pyrites and the role of fluid immiscibility in the deposition of invisible gold.

Genesis of the Xinfang magmatic-hydrothermal gold deposit, Liaodong Peninsula, China: Constraints from pyrite Re-Os isotopes, C, O, S, Pb, Si, He and Ar isotopes

The Xinfang gold deposit (>20 t@ 2.85 g/t) is situated in the southwest of the Liaodong Peninsula. Ore bodies are hosted by the Archean gneiss in the footwall and Neoproterozoic metasandstone in the hangingwall of the Xinfang Metamorphic Core Complex. Here, we conduct pyrite Re-Os dating, C, O, Si, He-Ar, S, and Pb isotopes in order to constrain the ore-forming age and genesis of the deposit. Field observations show that three ore-forming processes are recognized: (1) quartz- coarse-grained pyrite stage (stage Ⅰ), (2) quartz-polymetallic sulfide-gold stage (stage Ⅱ), and (3) quartz – calcite ± pyrite stage (stage III). Pyrite from the quartz-polymetallic sulfide-gold vein yielded Re-Os isochron age of 121.1 ± 1.2 Ma (Initial 187Os/188Os = 1.49 ± 0.01, MSWD = 1.2), which is interpreted to be the ore-formation age.Theδ13CV-PDB and 18Ov-SMO W values of calcite from stage III range from −5.1‰ to −4.9‰ and from 9.7‰ to 10.1‰, and the δ30Si values of quartz from stage Ⅰto stage III range from −0.5‰ to −0.4‰, −0.1‰ to −0.3‰, and −0.2‰ to −0.1‰, respectively, indicating that ore-forming fluids were derived from a magmatic-hydrothermal source. Sulfur isotopic compositions of sulfides between −1.9 ‰ and 4.4 ‰ (mean = 2.4 ‰), are consistent with that of magmatic sulfur. The galena yielded a wide range of lead isotopic composition (206Pb/204Pb = 16.995–17.252, 207Pb/204Pb = 15.335–16.343, 208Pb/204Pb = 37.461–37.580) suggesting an external lead source. The He and Ar isotope compositions of pyrite and galena (3He/4He = 0.14Ra-0.62Ra), indicate a crustal source with minor mantle contributions. Combining all available data results, we propose that a magmatic -hydrothermal source for the Xinfang gold deposit and the ore formation was related to the subduction of the Paleo-Pacific Plate beneath Eurasia.

Improved Air Stability of Sulfide Electrolytes for All-Solid-State Li Batteries

Sulfide-based solid electrolytes (SEs) are receiving increasing attention due to their high ionic conductivities (up to 10-2 S cm-1 at room temperature) that can be comparable to the liquid electrolytes.1 However, the air stability of sulfide SEs is very poor.2, 3 Most developed sulfide SEs are prone to turn bad when exposed to the moisture. The generated H2S is dangerous, which places the commercialization of sulfide SEs into a challenging situation. 2, 3 In our work, to improve the air stability of sulfide SEs, we employed element substitution (Sn and Sb) for the problematic element (P) in conventional sulfide SEs (Li3PS4, Li6PS5I, Li10GeP2S12) based on the hard and soft acid and base theory (HSAB).4, 5, 6 Our results suggest that Sn and Sb-substituted sulfide SEs show significantly improved air stability compared with the pristine sulfides. Meanwhile, it is found that the Sn or Sb element substitution effectively enhance the ionic conductivity as well as Li metal compatibility in some cases. Various structural (e.g., X-ray diffraction, X-ray absorption near edge spectroscopy, solid-state nuclear magnetic resonance) and electrochemical characterizations are employed to identify the mechanism of the improvements are related to the Sn/Sb substitution-derived crystal structure, reinforced bonding energy, and the optimized electrode/electrolyte interfaces. Our studies provide a new idea of designing functional sulfide composition to realize improved air stability coupling with other essential properties. Re ferences N. Kamaya, R. Kanno*, et al. A lithium superionic conductor, Nat. Mater. 2011, 10, 682-686.C. Yu, F. Zhao, J. Luo, X. Sun*. Recent Development of lithium argyrodite solid-state electrolytes for solid-state batteries: synthesis, structure, stability and dynamics. Nano Energy 2021, 83, 105858.F. Zhao, S. Zhang, Y. Li*, X. Sun*. Emerging characterization techniques to understand electrode interfaces in all-solid-state lithium batteries. Small Struct. 2021, DOI: 10.1002/sstr.202100146.F. Zhao, J. Liang, X. Sun*, et al. A Versatile Sn-Substituted Argyrodite Sulfide Electrolyte for All-Solid-State Li Metal Batteries, Adv. Energy Mater. 2020, 10, 1903422.F. Zhao, X. Sun*, et al. An Air-Stable and Li-Metal-Compatible Glass-Ceramic Electrolyte enabling High-Performance All-Solid-State Li-Metal Batteries. Adv. Mater. 2021, 33, 2006577.J. Liang, X. Sun*, et al. Li10Ge(P1–xSbx)2S12 Lithium-Ion Conductors with Enhanced Atmospheric Stability, Chem. Mater. 2020, 32, 2664-2672.

The Effect of Corrosion Conditions on Aging of Artificial Patina on Three Bronzes

The new bronze objects of art are almost always patinated before their exposure outdoors or indoors. Among the many patination methods used by practitioners, sulphide patination is one of the most common techniques. The aim of this work is to examine the corrosion behaviour of sulphide patinated bronzes under various aging conditions, including continuous immersion in simulated urban rain, alternating wet/dry cycles, and exposure to corrosion chamber with NO2 gas. The study was conducted on three types of bronzes with varying tin content. Corrosion characterisation of patinated bronze samples was performed by the means of electrochemical impedance spectroscopy and polarization measurements. Chemical composition and morphology of sulphide patinated bronze surface was examined by infrared spectroscopy and scanning electron microscopy. Obtained results show that freshly patinated bronze surfaces exhibit low corrosion resistance that gradually improves over time. An increase in corrosion resistance strongly depends on aging conditions, and it appears to be the highest under continuous immersion conditions.

The Gold–Palladium Ozernoe Occurrence (Polar Urals, Russia): Mineralogy, Conditions of Formation, Sources of Ore Matter and Fluid

We studied the mineralization and sulfur isotopic composition of sulfides of gold–palladium ores in olivine clinopyroxenites from the Dzelyatyshor massif made up of a continuous layered series of rocks: olivine-free clinopyroxenite–olivine clinopyroxenite–wehrlite. The primary igneous layering of rocks, manifested as different quantitative ratios of clinopyroxene and olivine in them, controls the local trends of variability in the chemistry of mineral-forming medium and the concentrations of ore components, including noble metals, and sulfur in each separate layer during its cooling. The replacement of primary rock-forming minerals by secondary minerals, when the temperature decreases, is a characteristic trend for pyroxenites: (a) olivine → serpentine, secondary magnetite, and (b) clinopyroxene → amphibole, secondary magnetite → chlorite. The deposition of native gold in parageneses with PGM and sulfides at the Ozernoe occurrence took place during the replacement of earlier rock-forming minerals by chlorite. This process completed mineral formation at the deposit and took place at temperatures 150–250 °C and at the high activity of S, Te, Sb, and As of fluid. The variability of mineral formation conditions during chloritization is reflected in the change of native-sulfide forms of Pd by arsenide-antimonide forms and the sulfur isotopic composition of sulfides. The Pd content in native gold increases in the series—Au-Ag solid solution (&lt;1.5 wt.% Pd)—Au-Cu intermetallides (to 6 wt.% Pd)—Cu-Au-Pd solid solutions (16.2–16.9 wt.% Pd). The sulfur isotopic composition of pyrite, chalcopyrite, and bornite varies from −2.1 to −2.9‰. It is assumed that a deep-seated magmatic basic melt was the source of fluid, ore components, and sulfur.

Effect of Rare Earth Cerium Content on Manganese Sulfide in U75V Heavy Rail Steel

To study the effect of Ce on the morphology of manganese sulfide, we added different contents of Ce into U75V heavy rail steel. The composition and morphology of sulfide in steel were analyzed. The inclusions’ number, size, and aspect ratio were analyzed by automatic scanning electron microscope ASPEX. The results show that the inclusions in heavy rail steel without Ce are elongated MnS and irregular Al-Si-Ca-O inclusions. With the increase of Ce from 52 ppm to 340 ppm, the composition of main inclusions changes along the route of Ce2O2S-MnS → Ce2O2S-MnS-Ce2S3 → Ce2O2S-Ce3S4-Ce2S3 → Ce2O2S-Ce3S4-CeS. Ce has a noticeable spheroidization effect on MnS, which can make inclusions finely dispersed. When Ce content is 139 ppm, the average size of inclusions is the smallest. The mechanism of Ce-modified MnS was discussed by combining experimental results with thermodynamic calculations. Finally, the effect of Ce treatment on inhibiting MnS deformation was verified by simulated rolling.

Geochemistry, sulfur and lead isotopic composition of hydrothermal sulfide from the Duanqiao hydrothermal field on the Southwest Indian Ridge: implications for ore genesis

ABSTRACT Hydrothermal activities on ultraslow-spreading ridges exhibit diverse characteristics, long histories with multiple participants, and might form large-scale, high-grade sulfide deposits. The Duanqiao hydrothermal field (DHF) is located at the segment with the thickest oceanic crust and a large axial magma chamber on the Southwest Indian Ridge, providing unique perspective of sulfide metallogenesis on ultraslow-spreading ridges. Previous studies revealed that DHF sulfide exhibits distinct features of enrichment of ore-forming elements in comparison with those of hydrothermal fields on sediment-starved mid-ocean ridges. However, the genesis and processes responsible for such differences remain poorly constrained. In this study, mineralogical, geochemical and S and Pb isotopic analyses were performed on relict sulfide mound samples to characterize DHF formation. The samples show clear concentric mineral zonation from the interior to the exterior wall. Assemblages of chalcopyrite, sphalerite, and pyrite are distributed mainly in the interior wall, whereas pyrite and marcasite are distributed mainly in the exterior wall. The low Cu content and Pb isotopic composition of the sulfide indicate that the metals are derived mainly from basement basalts. The δ34S values exhibit positive values distributed over a reasonably narrow range (2.42‰–7.97‰), which suggests approximately 62.1%–88.5% of S with basaltic origin. Compared with most hydrothermal fields along the sediment starved mid-ocean ridges, the DHF sulfide shows particularly high contents of Pb (263–2630 ppm), As (234–726 ppm), Sb (7.32–44.3 ppm), and Ag (35.2 to >100 ppm). The δ34S values exhibit an increasing tendency from the sample exterior to the interior. We propose that these features probably reflect the existence of a subsurface zone refining process. Our results provide new insight into the sulfide formation process and contribute to understanding the metallogenic mechanism of hydrothermal sulfides on ultraslow-spreading ridges.

The mineralization of Daxiao carbonate-hosted Pb-Zn deposit, northeast Yunnan province, SW China: Constraints from Rb-Sr isotopic dating and H[sbnd]O[sbnd]S-Pb isotopes

The Sichuan-Yunnan-Guizhou (SYG) Pb-Zn metallogenic province located in western Yangtze Block contains more than 400 carbonate-hosted Pb-Zn deposits. Uncertain mineralization age and ore-forming material source causing debates on the genesis of these carbonate-hosted Pb-Zn deposits. To address this issue, the Daxiao Pb-Zn deposit was chosen as a case study. The orebodies of Daxiao deposit are hosted in Mesoproterozoic Heishan formation argillaceous dolomite interbedded with slate. Three main mineralization stages have been identified, including syn-sedimentary stage, hydrothermal stage and supergene stage. The ore minerals consist of galena, sphalerite, chalcopyrite, argentite, smithsonite, anglesite and cerussite in the deposit. The early hydrothermal stage sphalerite yielded a Rb-Sr isochron age of 223.5 ± 2.9 Ma, consistent with the spike of Pb-Zn mineralization in SYG metallogenic province. Quartz in hydrothermal stage yields δDSMOW values of −69.6 to −65.8 ‰ and calculated δ18OFluid values of + 3.4 – +5.6 ‰, showing an affinity of metamorphic water. While the quartz in supergene stage yields δDSMOW values of −68.3 to −65.8 ‰ and calculated δ18OFluid values of −4.1 to −1.7 ‰, indicating abundant basinal brine or meteoric water had mixed into ore-forming fluid during its evolution from hydrothermal stage to supergene stage. Sulfur isotopic composition (δ34S = +6.3 – +19.1 ‰) of different stage sulfides reveal that the ore-forming sulfur originated from sulfates within the wall rocks, and mainly reduced by Thermal-chemical reduction (TSR). Moreover, the 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios of early hydrothermal stage sphalerite are 18.282 – 18.312, 15.603 – 15.681and 38.287 – 38.311, respectively. Those of late hydrothermal stage galena are 18.315 – 18.491, 15.676 – 15.721 and 38.314 – 38.326, respectively. All of them plot in the overlapping area of Emeishan flood basalts, Kunyang and Huili groups and Sinian to Triassic strata, indicating that these wall rocks jointly contributed the ore-forming metals for these Pb-Zn deposits in SYG metallogenic province. Hence, a metallogenic model for Daxiao and other carbonate-hosted Pb-Zn deposit in SYG metallogenic province was proposed: In the thrustfold systems caused by the subduction of Paleo-Pacific and the closure of Jinshajiang-Ailaoshan Paleo-Tethys ocean in Late Triassic to Early Jurassic. The fluids originated from metamorphic water migrated along deep faults and extracted ore-forming materials from wall rocks (including Proterozoic basement rocks, Sinian to Triassic sedimentary wall rocks and Permian Emeishan flood basalts), and then precipitated ores in the secondary thrust faults or interlayered fractures within these thrustfold systems.

Sulphur and metal sources of polymetallic vein-type, sedimentary exhalative-type and Mississippi Valley-type Zn–Pb deposits along the southeast margin of the Yangtze Block

Three types of zinc-lead deposits, including polymetallic vein-type, sedimentary-exhalative (SEDEX), and Mississippi valley-type (MVT) Zn–Pb deposits, have been discovered along the southeast margin of the Yangtze Block. A systematically comparative study on the sulphur and metal sources for these deposits, is absent, which significantly limits the understanding of the metallogenic model and geological exploration. Thus, in order to reveal the S and Pb sources of Pb–Zn deposits, an investigation of trace elements of sphalerite and of S–Pb isotopic compositions of sulphides in these three types of Zn–Pb deposits was conducted in this study. We found that, in the vein-type, SEDEX, and MVT Zn–Pb deposits, (1) the sulphur was derived respectively from granitic magmatism related to the Guangxi Orogeny, early Cambrian stratified seawater and connate water; (2) the lead isotope variation indicates that the ore-forming metals were mainly derived from the granitic hydrothermal fluids for vein-type deposits, from basement rocks for SEDEX deposits, and mainly from early Cambrian sedimentary rocks for MVT mineralization. The Nanhua rifting lead to the syngenetic Zn-Pb mineralization, while the Guangxi Orogeny resulted in magmatic-hydrothermal vein mineralization at depth and in MVT mineralization at the shallow crustal levels.

Sophora-like Nickel–Cobalt Sulfide and Carbon Nanotube Composites in Carbonized Wood Slice Electrodes for All-Solid-State Supercapacitors

Sophora-like Nickel–Cobalt Sulfide and Carbon Nanotube Composites in Carbonized Wood Slice Electrodes for All-Solid-State Supercapacitors

Consequence assessment considerations for toxic natural gas dispersion modeling

The numerical simulation of gas dispersion and estimation of consequence impact is of importance in Oil and Gas industry's process safety management. For natural gas fields with toxic components like Hydrogen sulfide, the toxicity impact zone drives business decisions related to equipment design, facility siting, layout, land use planning, and emergency response measures. Proprietary tools or empirical models which are calibrated using experiment database are often used for carrying out consequence modeling.The selection of a software tool and a suitable dispersion model, based on the cloud behavior, at the source of dispersion is critical for the impact zone estimation. It is observed that, the fluid phase and the cloud density are key for determining the appropriate dispersion model. Incorrect parameter selection could lead to an inaccurate consequence impact zone estimation. This in turn could result in disproportionate process risk management efforts especially for toxic impacts from exposure to a very low concentration.This paper discusses the results from consequence modeling studies done for a selected set of toxic natural gas release events related to onshore pipeline transfer using approved software. The study analyses the modeling inputs, parameters and determines the key release source terms and atmospheric parameters that impacts the estimation of impact zones. The study determined that the natural gas dispersion behaviour is dependent on the natural gas molar mass and the composition of Hydrogen sulfide. The study provides the guidance on overcoming uncertainty in dispersion modeling through sensitivity assessments and lists key parameters to be subjected for toxic natural gas dispersion modeling sensitivity analysis.

In-situ synthesis of NiS2 nanoparticles/MoS2 nanosheets hierarchical sphere anchored on reduced graphene oxide for enhanced electrocatalytic hydrogen evolution reaction

As an important energy storage and transportation carrier, hydrogen has the advantages of high combustion heat, non-toxic, and pollution-free energy conversion process. Bimetallic sulfide composites are one of the emerging catalysts for hydrogen evolution reactions (HER) during water splitting. Herein, a hydrothermal method has been employed for the in-situ synthesis of NiS2 nanoparticles/MoS2 nanosheets (NiS2/MoS2) hierarchical sphere anchored on reduced graphene oxide (RGO) for enhanced electrocatalytic HER activity. The NiS2/MoS2/RGO composite displays improved HER activity compared to MoS2/RGO and NiS2/RGO. The optimized NiS2/MoS2/RGO-9 requires only an overpotential of 136 mV at a current density of 10 mA cm−2, a small Tafel slope of 53.4 mV dec-1, and good stability in acid solution. The synergetic effect between NiS2 nanoparticles and MoS2 nanosheets is responsible for enhanced HER performance. Moreover, RGO provides the substrate for NiS2/MoS2 species and maintains the overall conductivity of NiS2/MoS2/RGO composites. Finally, density functional theory (DFT) calculations justify and approve the efficient HER activity of NiS2/MoS2/RGO in terms of lower Gibbs free energy (0.07 eV) and lower work function (3.98 eV) that subsequently enhance the dissociation of H2O.

The effects of highly reduced magmatism revealed through aubrites

AbstractEnstatite‐rich meteorites, including the aubrites, formed under conditions of very low oxygen fugacity (ƒO2: iron‐wüstite buffer −2 to −6) and thus offer the ability to study reduced magmatism present on multiple bodies in our solar system. Elemental partitioning among metals, sulfides, and silicates is poorly constrained at low ƒO2; however, studies of enstatite‐rich meteorites may yield empirical evidence of the effects of low ƒO2 on elemental behavior. This work presents comprehensive petrologic and oxygen isotopic studies of 14 aubrites, including four meteorites that have not been previously investigated in detail. The aubrites exhibit a variety of textures and mineralogy, and their elemental zoning patterns point to slow cooling histories for all 14 samples. Oxygen isotope analyses suggest that the aubrite parent bodies may be more heterogeneous than originally reported or may have experienced incomplete magmatic differentiation. Contrary to the other classified aubrites and based on textural and mineralogical observations, we suggest that the Northwest Africa 8396 meteorite shows an affinity for an enstatite chondrite parentage. By measuring major elemental compositions of silicates, sulfides, and metals, we calculate new metal–silicate, sulfide–silicate, and sulfide–metal partition coefficients for aubrites that are applicable to igneous systems at low ƒO2. The geochemical behavior of elements in aubrites, as determined using partition coefficients, is similar to the geochemical behavior of elements determined experimentally for magmatic systems on Mercury. Enstatite‐rich meteorites, including aubrites, represent valuable natural petrologic analogues to Mercury and their study could further our understanding of reduced magmatism in our solar system.

Age and mineralization processes of decratonic lode gold deposits in the southern North China Craton: Constraints from trace elements, in-situ S-Pb isotopes and Rb-Sr geochronology of pyrite from the Chen’er gold deposit

The Chen’er gold deposit, with 27 tons of known Au reserves, is one of the typical gold deposits in the Xiaoqinling district along the southern part of the North China Craton. In order to better understand the gold precipitation time and mineralization process, we report in-situ Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) trace element analyses, elemental maps, and the Rb-Sr and S-Pb isotopic composition of sulfides from the Chen’er gold deposit with a view to gain insights into the mineralization time and process. Trace element analyses and elemental maps of pyrite show that the content of As is low and has no correlation with Au, indicating As is unlikely to have controlled the Au incorporation into pyrite. Gold mainly occurs as solid solutions in the Py Ⅰ and Py Ⅱ, and as Au-Ag and/or Au-Te sub-micrometer inclusions in Py III. The Rb-Sr isotopic data on sulfides from the Chen’er deposit yielded an isochron age of 129.2 ± 3.4 Ma, which overlaps with the previously reported 40Ar/39Ar age of hydrothermal mica, indicating that the gold mineralization occurred in the Early Cretaceous. The in-situ sulfur isotope values of sulfides from stage Ⅱ to stage III fluctuate significantly (the average value decreases from 4.95 to −0.24‰) and were affected by physicochemical parameters of the mineralization process, especially ƒO2. In addition, the δ34S values are in a narrow range (-1.34 to 5.24‰), indicating a magmatic source for the sulfur. In-situ Pb isotopic compositions of the pyrite and galena of stage Ⅱ and stage III are relatively constant with 208Pb/204Pb, 207Pb/204Pb, and 206Pb/204Pb values in the range of 37.264–37.595, 15.364–15.423, 16.992–17.078, respectively, indicating a mixed mantle-crust origin. Based on the new geochronological, geochemical and isotopic data presented in this study, and combined with those from previous studies, we suggest that the lode gold deposits in the Xiaoqinling district are magmatic hydrothermal ore deposits, with metal and ore-forming fluid originating primarily from the mantle, coupled with the cratonic reactivation during the Early Cretaceous.

Fe‐Ni sulfides in Tagish Lake: Implications for nebular and parent body conditions of formation

AbstractThis study examined nine pristine samples representing seven lithologies of the ungrouped C2 carbonaceous chondrite Tagish Lake from the University of Alberta Meteorite Collection using scanning electron microscope and electron probe microanalyzer analyses to characterize the sulfide mineralogy, textures, and compositions present. Four distinct sulfide morphologies were identified including pyrrhotite containing exsolved pentlandite, unexsolved pyrrhotite, and unexsolved pentlandite, and a unique “bull’s‐eye” sulfide morphology. The at% Fe/Ni of the pyrrhotite grains within these samples decreases with increasing degree of alteration and roughly places them in the alteration order of TL11v chip1 &lt; TL4 &lt; TL11v chip2 &lt; TL5b ≤ TL10a &lt; TL 11h &lt; TL1 &lt; TL11i. The at% Fe/Ni of low Ni (&lt;1 wt% Ni) pyrrhotite indicates that the overall degree of alteration of Tagish Lake lies between that of CM1/2 and CI chondrites. Comparison of the composition of the sulfides to established Fe‐Ni‐S phase diagrams at different temperatures indicates two separate generations of sulfide formation. They are (1) high‐temperature formation of exsolved pyrrhotite–pentlandite and much of the unexsolved pentlandite at ~500–600 °C, likely by cooling of a monosulfide solid solution melt during chondrule formation; and (2) low‐temperature formation of unexsolved pyrrhotite, some unexsolved pentlandite, pyrrhotite containing flame‐like pentlandite bodies, and bull’s‐eye sulfides at ~25–100 °C, likely formed during aqueous alteration events on the Tagish Lake parent body.