Au‐Ag‐S‐Se‐Cl‐Br Mineralization at the Corrida Deposit (Russia) and Physicochemical Conditions of Ore Formation

The mineral and chemical compositions of ores from the Corrida epithermal Au-Ag deposit (Chukchi Peninsula, Russia) were studied using the optical and scanning electron microscopy with X-ray energy-dispersion microanalysis. The deposit was formed at the time close to the period when the basic volume of acid magmas had been emplaced within the Okhotsk–Chukotka belt (84 to 80 Ma). The Au–Ag mineralization is distinguished with Au-Ag sulphides and selenides (uytenbogaardtite-fischesserite solid solution, Se-acanthite, S-naumannite) and Ag halides of the chlorargyrite-embolite-bromargyrite series. The ores were formed in two stages. Using microthermometric methods, it has been established that the ore-bearing quartz was formed in the medium-temperature environment (340–160 °C) with the participation of low-salt (3.55 to 0.18 wt.% NaCl eq.) hydrotherms, mostly of the NaCl composition with magnesium, iron and low-density СО2. According to our results of thermodynamic modeling at temperatures from 300 to 25 °C and data on mineral metasomatic alterations of the host rocks, the Au-Ag-S-Se-Cl-Br mineralization was formed at decreasing temperature and fugacity of sulphur (logƒS2 from −6 to −27), selenium (logƒSe2 from −14 to −35), and oxygen (logƒО2 from −36 to −62), with near-neutral solutions replaced by acid solutions. Analysis of the obtained data shows that the Corrida refers to the group of the LS-type epithermal deposits. This deposit is a new example of epithermal deposits with significant quantities of Au–Ag chalcogenides (acanthite, uytenbogaardtite, fischesserite, naumannite and others).

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The Microstructure of Quasicrystalline Al-Cu-Fe Alloys Doped with Tungsten

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.203-204.372 ◽

2013 ◽

Vol 203-204 ◽

pp. 372-375 ◽

Cited By ~ 1

Author(s):

Wojciech Gurdziel ◽

Jacek Krawczyk ◽

Włodzimierz Bogdanowicz

Keyword(s):

Electron Microscope ◽

Induction Furnace ◽

Alloy Composition ◽

Solidification Process ◽

Icosahedral Phase ◽

Chemical Compositions ◽

X Ray ◽

Fe Alloys ◽

Two Stages ◽

Scanning Electron

The microstructure of Al65Cu20Fe14 (numbers indicate at.%) alloy doped with 1 at.% of W was studied. The selected alloy composition should allow to obtain the quasicrystalline icosahedral phase after solidification process. The bulk samples were obtained in two stages. At first, the synthesis of alloy through premelting of component elements in induction furnace and then, the directional solidification by the Bridgman method were performed. The morphology of selected areas of the samples were studied using Scanning Electron Microscope equipped with energy dispersive X-ray spectroscope, which was used to examine chemical compositions of each analysed areas. Additionally the X-ray powder diffraction was used to identify the phases present in the alloys. It was stated that the filaments of tungsten were present in the alloys. The filaments have thickness ranged from 0.01 to 2.5 μm. As a result of investigation, the arrangement of filaments in the material was determined.

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Improved Water–Gas Shift Performance of Au/NiAl LDHs Nanostructured Catalysts via CeO2 Addition

Nanomaterials ◽

10.3390/nano11020366 ◽

2021 ◽

Vol 11 (2) ◽

pp. 366

Author(s):

Margarita Gabrovska ◽

Ivan Ivanov ◽

Dimitrinka Nikolova ◽

Jugoslav Krstić ◽

Anna Maria Venezia ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Nanostructured Catalysts ◽

Water Gas Shift ◽

Precipitation Method ◽

Conversion Degree ◽

Pure Hydrogen ◽

Medium Temperature ◽

X Ray ◽

Supported Gold ◽

Water Gas

Supported gold on co-precipitated nanosized NiAl layered double hydroxides (LDHs) was studied as an effective catalyst for medium-temperature water–gas shift (WGS) reaction, an industrial catalytic process traditionally applied for the reduction in the amount of CO in the synthesis gas and production of pure hydrogen. The motivation of the present study was to improve the performance of the Au/NiAl catalyst via modification by CeO2. An innovative approach for the direct deposition of ceria (1, 3 or 5 wt.%) on NiAl-LDH, based on the precipitation of Ce3+ ions with 1M NaOH, was developed. The proposed method allows us to obtain the CeO2 phase and to preserve the NiAl layered structure by avoiding the calcination treatment. The synthesis of Au-containing samples was performed through the deposition–precipitation method. The as-prepared and WGS-tested samples were characterized by X-ray powder diffraction, N2-physisorption and X-ray photoelectron spectroscopy in order to clarify the effects of Au and CeO2 loading on the structure, phase composition, textural and electronic properties and activity of the catalysts. The reduction behavior of the studied samples was evaluated by temperature-programmed reduction. The WGS performance of Au/NiAl catalysts was significantly affected by the addition of CeO2. A favorable role of ceria was revealed by comparison of CO conversion degree at 220 °C reached by 3 wt.% CeO2-modified and ceria-free Au/NiAl samples (98.8 and 83.4%, respectively). It can be stated that tuning the properties of Au/NiAl LDH via CeO2 addition offers catalysts with possibilities for practical application owing to innovative synthesis and improved WGS performance.

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New Insights into the Crystal Chemistry of Elpidite, Na2Zr[Si6O15]·3H2O and (Na1+YCax□1−X−Y)Σ=2Zr[Si6O15]·(3−X)H2O, and Ab Initio Modeling of IR Spectra

Materials ◽

10.3390/ma14092160 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2160

Author(s):

Alexander Bogdanov ◽

Ekaterina Kaneva ◽

Roman Shendrik

Keyword(s):

Ir Spectra ◽

Structural Models ◽

Chemical Characterization ◽

Chemical Compositions ◽

X Ray Diffraction ◽

Special Group ◽

X Ray ◽

Influence Of Water ◽

Radioactive Species

Elpidite belongs to a special group of microporous zirconosilicates, which are of great interest due to their capability to uptake various molecules and ions, e.g., some radioactive species, in their structural voids. The results of a combined electron probe microanalysis and single-crystal X-ray diffraction study of the crystals of elpidite from Burpala (Russia) and Khan-Bogdo (Mongolia) deposits are reported. Some differences in the chemical compositions are observed and substitution at several structural positions within the structure of the compounds are noted. Based on the obtained results, a detailed crystal–chemical characterization of the elpidites under study was carried out. Three different structure models of elpidite were simulated: Na2ZrSi6O15·3H2O (related to the structure of Russian elpidite), partly Ca-replaced Na1.5Ca0.25ZrSi6O15·2.75H2O (close to elpidite from Mongolia), and a hypothetical CaZrSi6O15·2H2O. The vibration spectra of the models were obtained and compared with the experimental one, taken from the literature. The strong influence of water molecule vibrations on the shape of IR spectra of studied structural models of elpidite is discussed in the paper.

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Cotton stalk-derived hydrothermal carbon for methylene blue dye removal: investigation of the raw material plant tissues

Bioresources and Bioprocessing ◽

10.1186/s40643-021-00364-8 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Libo Zhang ◽

Junyan Tan ◽

Gangying Xing ◽

Xintong Dou ◽

Xuqiang Guo

Keyword(s):

Methylene Blue ◽

Functional Materials ◽

Raw Material ◽

Plant Tissues ◽

Chemical Compositions ◽

Waste Biomass ◽

Cotton Stalk ◽

Acid Base ◽

X Ray ◽

Bet Analysis

AbstractConversion of the abundant agricultural residual cotton stalk (CS) into useful chemicals or functional materials could alleviate the fossil fuels caused energy shortages and environmental crises. Although some advances have been achieved, less attention has been paid to the plant tissues effect. In this study, the plant tissue of CS was changed by part degradation of some components (hemicelluloses and lignin, for example) with the aid of acid/base (or both). The pretreated CS was transformed into hydrochar by hydrothermal carbonization (HTC) method. Morphological and chemical compositions of CS hydrochar were analyzed by various techniques, including elemental analysis, Fourier transform infrared (FTIR), BET analysis, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Methylene blue (MB) removal of prepared CS hydrochar was used to evaluate CS hydrochar pollutions adsorption capacity. Results reveal acid/base (or both) pretreatment is beneficial for CS raw material to prepare high-quality CS hydrochar. The effects of some parameters, such as initial MB concentration, temperature, pH value and recyclability on the adsorption of MB onto both acid and base-pretreated CS hydrochar (CS-H2SO4 + NaOH-HTC) were studied. The present work exhibits the importance of agricultural waste biomass material plant tissues on its derived materials, which will have a positive effect on the direct utilization of waste biomass.

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Magnetically Recyclable Wool Keratin Modified Magnetite Powders for Efficient Removal of Cu2+ Ions from Aqueous Solutions

Nanomaterials ◽

10.3390/nano11051068 ◽

2021 ◽

Vol 11 (5) ◽

pp. 1068

Author(s):

Xinyue Zhang ◽

Yani Guo ◽

Wenjun Li ◽

Jinyuan Zhang ◽

Hailiang Wu ◽

...

Keyword(s):

Electron Microscopy ◽

Aqueous Solutions ◽

Adsorption Capacity ◽

Surface Area ◽

Ion Concentration ◽

Bet Surface Area ◽

Chemical Compositions ◽

Ion Adsorption ◽

X Ray ◽

Wool Keratin

The treatment of wastewater containing heavy metals and the utilization of wool waste are very important for the sustainable development of textile mills. In this study, the wool keratin modified magnetite (Fe3O4) powders were fabricated by using wool waste via a co-precipitation technique for removal of Cu2+ ions from aqueous solutions. The morphology, chemical compositions, crystal structure, microstructure, magnetism properties, organic content, and specific surface area of as-fabricated powders were systematically characterized by various techniques including field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), thermogravimetric (TG) analysis, and Brunauer–Emmett–Teller (BET) surface area analyzer. The effects of experimental parameters such as the volume of wool keratin hydrolysate, the dosage of powder, the initial Cu2+ ion concentration, and the pH value of solution on the adsorption capacity of Cu2+ ions by the powders were examined. The experimental results indicated that the Cu2+ ion adsorption performance of the wool keratin modified Fe3O4 powders exhibited much better than that of the chitosan modified ones with a maximum Cu2+ adsorption capacity of 27.4 mg/g under favorable conditions (0.05 g powders; 50 mL of 40 mg/L CuSO4; pH 5; temperature 293 K). The high adsorption capacity towards Cu2+ ions on the wool keratin modified Fe3O4 powders was primarily because of the strong surface complexation of –COOH and –NH2 functional groups of wool keratins with Cu2+ ions. The Cu2+ ion adsorption process on the wool keratin modified Fe3O4 powders followed the Temkin adsorption isotherm model and the intraparticle diffusion and pseudo-second-order adsorption kinetic models. After Cu2+ ion removal, the wool keratin modified Fe3O4 powders were easily separated using a magnet from aqueous solution and efficiently regenerated using 0.5 M ethylene diamine tetraacetic acid (EDTA)-H2SO4 eluting. The wool keratin modified Fe3O4 powders possessed good regenerative performance after five cycles. This study provided a feasible way to utilize waste wool textiles for preparing magnetic biomass-based adsorbents for the removal of heavy metal ions from aqueous solutions.

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Structure and Characterization of TiC/GLC Multilayered Films with Various Bilayers Periods

Coatings ◽

10.3390/coatings11070787 ◽

2021 ◽

Vol 11 (7) ◽

pp. 787

Author(s):

Weiqi Wang ◽

Xiaoming Ling ◽

Rui Wang ◽

Wenhao Nie ◽

Li Ji ◽

...

Keyword(s):

Electron Microscopy ◽

Photoelectron Spectroscopy ◽

Chemical Compositions ◽

Closed Field ◽

Multilayered Structures ◽

Multilayered Films ◽

Sputtering Deposition ◽

X Ray ◽

Mechanical And Tribological Properties ◽

Self Organizing

The spontaneously self-organizing multilayered graphite-like carbon (denoted as GLC) /TiC films with various bilayer periods in the range of 13.3–17.5 nm were deposited on silicon and 1Cr18Mn8Ni5N stainless steel substrates using closed field magnetron sputtering deposition facility. The microstructures and chemical compositions of the prepared multilayered films were characterized by scanning electron microscopy, high resolution transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy respectively. The self-organizing multilayered structures in all of the films consisted of titanium carbide layers and sp2-rich carbon layers periodically alternate arrangement. The TiC contents and bilayer periods of the multilayered films can be controlled by means of adjusting of sputtering current of graphite target. Furthermore, the mechanical and tribological performances of the prepared films were appraised by nano-indentor, scratch measures, and ball-on-plate tribometer respectively. The results indicated that multilayer structure endowed the as-deposited TiC/GLC films outstanding mechanical and tribological properties, especially the multilayer film with 15.9 nm bilayer period deposited at 10 A sputtering current showed the excellent adhesion strength and hardness; Simultaneously it also exhibited the lowest average friction coefficient in the humid environment owing to its high content of sp2 hybrid carbon.

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Geochemical signatures of mineralizing events in the Juomasuo Au–Co deposit, Kuusamo belt, northeastern Finland

Mineralium Deposita ◽

10.1007/s00126-020-01039-8 ◽

2021 ◽

Author(s):

Mikael Vasilopoulos ◽

Ferenc Molnár ◽

Hugh O’Brien ◽

Yann Lahaye ◽

Marie Lefèbvre ◽

...

Keyword(s):

Trace Element ◽

Sulfur Isotope ◽

Mineral Chemistry ◽

Chemical Compositions ◽

Metasedimentary Rocks ◽

Metavolcanic Rocks ◽

Icp Ms ◽

Stage 1 ◽

Host Rocks ◽

Relationship Of

AbstractThe Juomasuo Au–Co deposit, currently classified as an orogenic gold deposit with atypical metal association, is located in the Paleoproterozoic Kuusamo belt in northeastern Finland. The volcano-sedimentary sequence that hosts the deposit was intensely altered, deformed, and metamorphosed to greenschist facies during the 1.93–1.76 Ga Svecofennian orogeny. In this study, we investigate the temporal relationship between Co and Au deposition and the relationship of metal enrichment with protolith composition and alteration mineralogy by utilizing lithogeochemical data and petrographic observations. We also investigate the nature of fluids involved in deposit formation based on sulfide trace element and sulfur isotope LA-ICP-MS data together with tourmaline mineral chemistry and boron isotopes. Classification of original protoliths was made on the basis of geochemically immobile elements; recognized lithologies are metasedimentary rocks, mafic, intermediate-composition, and felsic metavolcanic rocks, and an ultramafic sill. The composition of the host rocks does not control the type or intensity of mineralization. Sulfur isotope values (δ34S − 2.6 to + 7.1‰) and trace element data obtained for pyrite, chalcopyrite, and pyrrhotite indicate that the two geochemically distinct Au–Co and Co ore types formed from fluids of different compositions and origins. A reduced, metamorphic fluid was responsible for deposition of the pyrrhotite-dominant, Co-rich ore, whereas a relatively oxidized fluid deposited the pyrite-dominant Au–Co ore. The main alteration and mineralization stages at Juomasuo are as follows: (1) widespread albitization that predates both types of mineralization; (2) stage 1, Co-rich mineralization associated with chlorite (± biotite ± amphibole) alteration; (3) stage 2, Au–Co mineralization related to sericitization. Crystal-chemical compositions for tourmaline suggest the involvement of evaporite-related fluids in formation of the deposit; boron isotope data also allow for this conclusion. Results of our research indicate that the metal association in the Juomasuo Au–Co deposit was formed by spatially coincident and multiple hydrothermal processes.

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X-Ray Photoelectron Spectroscopy Study on Reduction of Graphene Oxide with Hydrazine Hydrate

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.287-290.539 ◽

2011 ◽

Vol 287-290 ◽

pp. 539-543 ◽

Cited By ~ 5

Author(s):

Wen Shi Ma ◽

Jun Wen Zhou ◽

Xiao Dan Lin

Keyword(s):

Graphene Oxide ◽

Hydrazine Hydrate ◽

Photoelectron Spectroscopy ◽

Reduction Rate ◽

Reduction Reaction ◽

Chemical Compositions ◽

Total Oxygen ◽

Graphene Oxides ◽

X Ray ◽

Oxygen Groups

Graphene oxide was prepared through Hummers' method，then different reduced graphenes were prepared via reduction of graphene oxide with hydrazine hydrate for 1h、12h and 24h. X-ray photoelectron spectroscopy (XPS) was used for the characterization of graphene oxide and the reduced graphenes. The variation of the contents of carbon in carbon and oxygen functional groups and chemical compositions of graphene oxides were investigated through analysis the content of different carbon atoms in different reduced graphenes. The results showed that the reduction reaction was very fast in the first 1 h, the content of total oxygen bonded carbon atoms decreased from 83.6% to 22.1%, and then after the reduction rate became very slow. After 12h, the content of total oxygen bonded carbon atom is 19.56%, only 2.54% lower than that of 1h’s. At the same time, C-N was introduced in the graphene oxides; this increased the stereo-hindrance for hydrazine hydrate attacking the C-Oxygen groups, thus reduced the reduction rate. After reduction for 24h, there still exists 16.4% oxygen bonded carbon atoms and the total conversion ratio of graphene approaches 70%.

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Plastic deformations in kyanites by tectonometamorphic processes: a single-crystal X-ray diffraction study

Mineralogical Magazine ◽

10.1180/minmag.2009.073.3.359 ◽

2009 ◽

Vol 73 (3) ◽

pp. 359-371 ◽

Cited By ~ 5

Author(s):

G. D. Gatta ◽

N. Rotiroti ◽

M. Zucali

Keyword(s):

Single Crystal ◽

X Ray Diffraction ◽

Plastic Deformations ◽

X Ray ◽

Deformational History ◽

Significant Difference ◽

Elliptical Section ◽

History Of ◽

Diffraction Patterns ◽

Two Stages

AbstractThe crystalch emistry and crystal structure of naturalky anite crystals from the Eclogitic Micaschists Complex of the Sesia-Lanzo Zone, Western Italian Alps, have been investigated by means of optical microscopy, wavelength dispersive X-ray microanalysis, and single-crystal X-ray diffraction. The association of kyanite + garnet + phengitic-mica + chloritoid suggests that the eclogite-facies stages occurred at P ≤ 2.1 GPa and T ≤ 650ºC. Kyanite grains are large (cm-sized) porphyroblasts grown dynamically during one of the deformational events related to the subduction of the Austroalpine continentalcr ust. Under the polarizing microscope, kyanite grains show almost homogeneous cores, whereas rims are sometimes symplectitic aggregates of quartz and kyanite, confirming at least two stages of growth most likely related to the multistage deformational history of these rocks. Chemical analysis shows that Fe3+ is the major substituting cation for Al3+, ranging between 0.038 and 0.067 a.p.f.u.The single-crystal X-ray diffraction investigation of the kyanites shows severely textured patterns on the (h0l)*-plane. Such evidence is not observed in the unwarped diffraction patterns on (0kl)* and (hk0)*. The most significant difference between the structuralp arameters refined in this study, with respect to those of previously published unstrained gem-quality crystals, concerns the displacement parameters. The anisotropic displacement ellipsoids of all the atomic sites are significantly larger than those previously described, and systematically oriented with the largest elliptical section almost perpendicular to [010]. The larger ellipsoids in the kyanite crystal investigated here reflect the displacement of the centre of gravity of the electron distribution, rather than an anomalous atomic thermal motion. The magnitude and orientation of the displacement parameters and the textured/strained diffraction pattern may be the result of two combined effects: (1) that the kyanite crystals are actually composed of several blocks; (2) the crystals are affected by a pervasive residual strain, as a result of tectonometamorphic plastic deformations and re-crystallization.

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Growth mechanism and characterization of ZnO nano-tubes synthesized using the hydrothermal-etching method

Chemical Papers ◽

10.2478/s11696-009-0082-y ◽

2009 ◽

Vol 63 (6) ◽

Cited By ~ 10

Author(s):

Yan Li ◽

Chuan-Sheng Liu ◽

Yun-Ling Zou

Keyword(s):

Room Temperature ◽

Morphological Analysis ◽

Diffraction Field ◽

X Ray Diffraction ◽

X Ray ◽

Room Temperature Photoluminescence ◽

Etching Method ◽

Nano Rods ◽

Two Stages

AbstractZnO nano-tubes (ZNTs) have been successfully synthesized via a simple hydrothermal-etching method, and characterized by X-ray diffraction, field emission scanning electron microscopy and room temperature photoluminescence measurement. The as-synthesized ZNTs have a diameter of 500 nm, wall thickness of 20–30 nm, and length of 5 µm. Intensity of the plane (0002) diffraction peak, compared with that of plane (10$$ \bar 1 $$0) of ZNTs, is obviously lower than that of ZnO nano-rods. This phenomenon can be caused by the smaller cross section of plane (0002) of the nano-tubes compared with that of other morphologies. On basis of the morphological analysis, the formation process of nano-tubes can be proposed in two stages: hydrothermal growth and reaction etching process.

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