Artykuły w czasopismach na temat „Metal sulphides”
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1
Barnes, Sarah-Jane, M. L. Zientek i M. J. Severson. "Ni, Cu, Au, and platinum-group element contents of sulphides associated with intraplate magmatism: a synthesis". Canadian Journal of Earth Sciences 34, nr 4 (1.04.1997): 337–51. http://dx.doi.org/10.1139/e17-030.
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The tectonic setting of intraplate magmas, typically a plume intersecting a rift, is ideal for the development of Ni – Cu – platinum-group element-bearing sulphides. The plume transports metal-rich magmas close to the mantle–crust boundary. The interaction of the rift and plume permits rapid transport of the magma into the crust, thus ensuring that no sulphides are lost from the magma en route to the crust. The rift may contain sediments which could provide the sulphur necessary to bring about sulphide saturation in the magmas. The plume provides large volumes of mafic magma; thus any sulphides that form can collect metals from a large volume of magma and consequently the sulphides will be metal rich. The large volume of magma provides sufficient heat to release large quantities of S from the crust, thus providing sufficient S to form a large sulphide deposit. The composition of the sulphides varies on a number of scales: (i) there is a variation between geographic areas, in which sulphides from the Noril'sk–Talnakh area are the richest in metals and those from the Muskox intrusion are poorest in metals; (ii) there is a variation between textural types of sulphides, in which disseminated sulphides are generally richer in metals than the associated massive and matrix sulphides; and (iii) the massive and matrix sulphides show a much wider range of compositions than the disseminated sulphides, and on the basis of their Ni/Cu ratio the massive and matrix sulphides can be divided into Cu rich and Fe rich. The Cu-rich sulphides are also enriched in Pt, Pd, and Au; in contrast, the Fe-rich sulphides are enriched in Fe, Os, Ir, Ru, and Rh. Nickel concentrations are similar in both. Differences in the composition between the sulphides from different areas may be attributed to a combination of differences in composition of the silicate magma from which the sulphides segregated and differences in the ratio of silicate to sulphide liquid (R factors). The higher metal content of the disseminated sulphides relative to the massive and matrix sulphides may be due to the fact that the disseminated sulphides equilibrated with a larger volume of magma than massive and matrix sulphides. The difference in composition between the Cu- and Fe-rich sulphides may be the result of the fractional crystallization of monosulphide solid solution from a sulphide liquid, with the Cu-rich sulphides representing the liquid and the Fe-rich sulphides representing the cumulate.
2
Vikentyev, Ilya, Olga Vikent’eva, Eugenia Tyukova, Maximilian Nikolsky, Julia Ivanova, Nina Sidorova, Dmitry Tonkacheev i in. "Noble Metal Speciations in Hydrothermal Sulphides". Minerals 11, nr 5 (3.05.2021): 488. http://dx.doi.org/10.3390/min11050488.
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A significant part of the primary gold reserves in the world is contained in sulphide ores, many types of which are refractory in gold processing. The deposits of refractory sulphide ores will be the main potential source of gold production in the future. The refractory gold and silver in sulphide ores can be associated with micro- and nano-sized inclusions of Au and Ag minerals as well as isomorphous, adsorbed and other species of noble metals (NM) not thoroughly investigated. For gold and gold-bearing deposits of the Urals, distribution and forms of NM were studied in base metal sulphides by laser ablation-inductively coupled plasma mass spectrometry and by neutron activation analysis. Composition of arsenopyrite and As-pyrite, proper Au and Ag minerals were identified using electron probe microanalysis. The ratio of various forms of invisible gold—which includes nanoparticles and chemically bound gold—in sulphides is discussed. Observations were also performed on about 120 synthetic crystals of NM-doped sphalerite and greenockite. In VMS ores with increasing metamorphism, CAu and CAg in the major sulphides (sphalerite, chalcopyrite, pyrite) generally decrease. A portion of invisible gold also decreases —from ~65–85% to ~35–60% of the total Au. As a result of recrystallisation of ores, the invisible gold is enlarged and passes into the visible state as native gold, Au-Ag tellurides and sulphides. In the gold deposits of the Urals, the portion of invisible gold is usually <30% of the bulk Au.
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Smyk, Mark C., i David H. Watkinson. "Sulphide remobilization in Archean volcano-sedimentary rocks and its significance in Proterozoic silver vein genesis, Cobalt, Ontario". Canadian Journal of Earth Sciences 27, nr 9 (1.09.1990): 1170–81. http://dx.doi.org/10.1139/e90-124.
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The Archean volcano-sedimentary succession at Cobalt, Ontario, consists mainly of submarine andesitic flows and turbiditic interflow sedimentary rocks. Steeply dipping faults and large-scale, tight to isoclinar folds have developed in these basement rocks. The faults commonly host silver-vein-bearing structures that extend upward into overlying Proterozoic units. Synvolcanic and synsedimentary base metal sulphide deposits are ubiquitous in the Archean rocks. Epigenetic sulphide mineralization consists of remobilized and replacement sulphides and minor sulpharsenides. Epigenetic sulphides occur in permeable rocks and in fault and fracture zones, commonly in juxtaposition with silver veins.The coincidence of silver veins and structures containing remobilized sulphides suggests that sulphide remobilization from Archean basement rocks into Proterozoic vein-bearing structures predated or accompanied vein development. Sulphide remobilization may have also facilitated the mobilization (leaching) of metals from basement sulphides into the vein-forming hydrothermal fluids.
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Prokkola, Hanna, Emma-Tuulia Nurmesniemi i Ulla Lassi. "Removal of Metals by Sulphide Precipitation Using Na2S and HS−-Solution". ChemEngineering 4, nr 3 (4.09.2020): 51. http://dx.doi.org/10.3390/chemengineering4030051.
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Precipitation of metals as metal sulphides is a practical way to recover metals from mine water. Sulphide precipitation is useful since many metals are very sparingly soluble as sulphides. Precipitation is also pH dependent. This article investigates the precipitation of metals individually as sulphides and assesses which metals are precipitated as metal hydroxides by adjustment of the pH. The precipitation of different metals as sulphides was studied to determine the conditions under which the HS− solution from the sulphate reduction reaction could be used for precipitation. H2S gas and ionic HS− produced during anaerobic treatment could be recycled from the process to precipitate metals in acidic mine drainage (AMD) prior to anaerobic treatment (Biological sulphate reduction), thereby recovering several metals. Precipitation of metals with HS− was fast and produced fine precipitates. The pH of acid mine water is about 2–4, and it can be adjusted to pH 5.5 before sulphide precipitation, while the precipitation, on the other hand, requires a sulphide solution with pH at 8 and the sulphide in HS− form. This prevents H2S formation and mitigates the risk posed from the evaporation of toxic hydrogen sulphur gas. This is a lower increase than is required for hydroxide precipitation, in which pH is typically raised to approximately nine. After precipitation, metal concentrations ranged from 1 to 30 μg/L.
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Ofori-Sarpong, G., D. K. Adjei i R. K. Amankwah. "Fungal-Transformation of Surrogate Sulphides and Carbonaceous Matter in Refractory Gold Ores: Revisited". Ghana Mining Journal 17, nr 2 (13.12.2017): 56–65. http://dx.doi.org/10.4314/gm.v17i2.8.
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In the recovery of gold from refractory gold ores, pretreatment is required to decompose sulphides and liberate occluded gold before cyanidation, and to deactivate carbonaceous matter and prevent it from adsorbing dissolved gold. Until the past three decades, most commercial pretreatment processes had been by abiotic means. Biological pretreatment methods on commercial basis is therefore a recent phenomenon, and several researches are underway to assess the ability of different biological agents in the breakdown of sulphur and carbonaceous matter (CM) in gold ores. This paper, which is a revisit of an earlier one, presents an overview of on-going research aimed at assessing the capability of the fungus, Phanerochaete chrysosporium, to degrade sulphides and CM. Surrogate carbonaceous materials (lignite, bituminous and anthracite coals) and pure sulphides (pyrite and arsenopyrite) were used to model the behavior of CM and sulphides in refractory gold ores. To monitor the extent of biotransformation, preg-robbing test was conducted on the as-received and treated CM, and sulphide sulphur in the residual sulphidic materials was also determined. From an initial preg-robbing effect of 125 µg of gold per gram of CM, the ability of CM to preg-rob gold reduced by 70-95% in the order of lignite<bituminous <anthracite within 21 days of treatment, whereas there were 18% and 39% oxidation of sulphide sulphur in pyrite and arsenopyrite respectively. XRD examination of the treated anthracite confirmed reduction in the graphitic structure of carbon following fungal transformation. Similarly, there was a decline in the major sulphide peak after microbial pretreatment. The results indicate that the fungus biotransforms through destruction of the ordered structure, followed by introduction of oxygen groups. The amorphous nature, thus generated, inhibits the uptake of aurocyanide ions by CM, while enhancing the affinity of cyanide for the oxidised sulphide material in subsequent cyanidation treatment. The findings contribute to knowledge on novel and technically viable alternative methods for oxidative pretreatment of refractory gold ores. Keywords: Phanerochaete Chrysosporium, Carbonaceous Matter, Metal Sulphides, Biotransformation
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Merkle, Roland K. W. "Platinum-group minerals in the middle group of chromitite layers at Marikana, western Bushveld Complex: indications for collection mechanisms and postmagmatic modification". Canadian Journal of Earth Sciences 29, nr 2 (1.02.1992): 209–21. http://dx.doi.org/10.1139/e92-020.
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The platinum-group minerals in a drill core taken through the middle group of chromitite layers in the Critical Zone at Marikana in the western Bushveld Complex were found to consist mainly of laurite as inclusions in chromite grains. The platinum-group minerals containing Pt, Pd, and Rh are concentrated in the intercumulus silicates and frequently associated with base-metal sulphides. Up to about 20% of all platinum-group minerals in the investigated chromitite layers contain sub stantial amounts of As. The base-metal sulphides are strongly modified in the postmagmatic stage, which led to a significant loss of Fe and S, in this way concentrating Cu, Ni, and the platinum-group elements by factors of up to 10. Interaction between chromite and base-metal sulphides cannot account for all the Fe lost in chromite-poor samples, and the importance of additional processes is indicated. Inclusions in chromite and orthopyroxene indicate the formation of discrete platinum-group minerals and As-rich phases before the formation of an immiscible sulphide melt. Resorption of earlier formed platinum-group minerals into the immiscible sulphide melt and postmagmatic sulphidation destroyed most of the evidence of the early formed platinum-group minerals.
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Pieczonka, Jadwiga. "Polymetallic mineralization in Triassic strata of the NW part of the Kraków-Częstochowa Monocline". Mineralogia 41, nr 1-2 (1.01.2010): 35–53. http://dx.doi.org/10.2478/v10002-010-0004-1.
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Polymetallic mineralization in Triassic strata of the NW part of the Kraków-Częstochowa MonoclineA new association of ore minerals has been found in the Lower and Middle Triassic rocks in the vicinity of the village of Woźniki in the NW part of the Upper Silesian district. In addition to the typical Zn-Pb-Fe association in dolomites, copper sulphides have been detected in the sandstones and conglomerates of the Lower Bunter. Copper mineralization occurs in the sandstone matrix and is represented by bornite, chalcopyrite, chalcocite, tetrahedrite and covellite. High admixtures of zinc in Cu sulphides and admixtures of copper in Zn-Pb sulphides suggest a common source for the metal-transporting fluids and a single period of sulphide crystallization.
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Eliopoulos, Demetrios G., Maria Economou-Eliopoulos, George Economou i Vassilis Skounakis. "Mineralogical and Geochemical Constraints on the Origin of Mafic–Ultramafic-Hosted Sulphides: The Pindos Ophiolite Complex". Minerals 10, nr 5 (18.05.2020): 454. http://dx.doi.org/10.3390/min10050454.
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Sulphide ores hosted in deeper parts of ophiolite complexes may be related to either primary magmatic processes or links to hydrothermal alteration and metal remobilization into hydrothermal systems. The Pindos ophiolite complex was selected for the present study because it hosts both Cyprus-type sulphides (Kondro Hill) and Fe–Cu–Co–Zn sulphides associated with magnetite (Perivoli-Tsoumes) within gabbro, close to its tectonic contact with serpentinized harzburgite, and thus offers the opportunity to delineate constraints controlling their origin. Massive Cyprus-type sulphides characterized by relatively high Zn, Se, Au, Mo, Hg, and Sb content are composed of pyrite, chalcopyrite, bornite, and in lesser amounts covellite, siegenite, sphalerite, selenide-clausthalite, telluride-melonite, and occasionally tennantite–tetrahedrite. Massive Fe–Cu–Co–Zn-type sulphides associated with magnetite occur in a matrix of calcite and an unknown (Fe,Mg) silicate, resembling Mg–hisingerite within a deformed/metamorphosed ophiolite zone. The texture and mineralogical characteristics of this sulphide-magnetite ore suggest formation during a multistage evolution of the ophiolite complex. Sulphides (pyrrhotite, chalcopyrite, bornite, and sphalerite) associated with magnetite, at deeper parts of the Pindos (Tsoumes), exhibit relatively high Cu/(Cu + Ni) and Pt/(Pt + Pd), and low Ni/Co ratios, suggesting either no magmatic origin or a complete transformation of a preexisting magmatic assemblages. Differences recorded in the geochemical characteristics, such as higher Zn, Se, Mo, Au, Ag, Hg, and Sb and lower Ni contents in the Pindos compared to the Othrys sulphides, may reflect inheritance of a primary magmatic signature.
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Harris, D. L., i B. G. Lottermoser. "Phosphate stabilization of polyminerallic mine wastes". Mineralogical Magazine 70, nr 1 (luty 2006): 1–13. http://dx.doi.org/10.1180/0026461067010309.
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AbstractPolyminerallic, sulphidic mine wastes were treated with KH2PO4-H2O2 solutions to determine whether the formation of solid phosphate coatings inhibits sulphide oxidation and metal and metalloid mobility. The waste rocks were metal (PbZnCu) and metalloid (AsSb) rich and consisted of major quartz, dickite, illite and sulphide minerals (e.g. galena, chalcopyrite, tetrahedrite, sphalerite, pyrite, arsenopyrite) as well as minor to trace amounts of pre- and post-mining oxidation products (e.g. oxides, hydroxides, arsenates and sulphates). Scanning electron microscopy observations of the waste material treated with KH2PO4-H2O2 solutions showed that metal, metal-alkali and alkali phosphate precipitates formed and coatings developed on all sulphides (with the exception of tetrahedrite). The abundance of phosphate phases was dependant on the availability of metal and alkali cations in solution. In turn, the release of cations was dependent on the amount of sulphide oxidation induced during the experiment or the presence of soluble oxidation products. Lead and to a lesser degree Cu and Zn phosphate coatings remained stable during H2O2 leaching, preventing acid generation and metal release. In contrast, the lack of phosphate coating on tetrahedrite and arsenopyrite allowed oxidation and leaching of As and Sb to proceed and mobilized As and Sb did not form phosphate phases. As a result, As and Sb displayed the greatest release from the coated waste. Thus, the application of KH2PO4-H2O2 solutions to partly oxidized, polyminerallic mine wastes suppresses sulphide oxidation and is most effective in inhibiting Pb (Cu and Zn) release. However, the technique appears ineffective in preventing metalloid (As, Sb) leaching from tetrahedrite- and arsenopyrite-bearing wastes.
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Zhang, YiRan, Nawoong Yoon i Maria E. Holuszko. "Assessment of Sortability Using a Dual-Energy X-ray Transmission System for Studied Sulphide Ore". Minerals 11, nr 5 (4.05.2021): 490. http://dx.doi.org/10.3390/min11050490.
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In hard rock mining, sensor-based sorting can be applied as a pre-concentration method before the material enters the mill. X-ray transmission sensors have been explored in mining since 1972. Sorting ore of acceptable grade and waste material before processing at the mill can reduce the amount of tailings per unit of valuable metal in the mining operation and have many economic benefits. Ore samples used in this paper are from a polymetallic carbonate replacement deposit (gold-silver-lead-zinc sulphide) in Southeast Europe. This paper focuses on how the Dual-Energy X-ray Transmission (DE-XRT) data is generated and used for ore characterization and sortability for this sulphide ore. The method used in the DE-XRT analysis in this project is based on the dual-material decomposition method, which is used in the medical industry for radiology. This technique can distinguish sulphides from non-sulphides. However, the correlation developed between the DE-XRT response and the metal content is lacking. As a result, the DE-XRT response can only classify the material effectively but cannot reliably predict the metal content.
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Al-Tarazi, Mousa, A. Bert M. Heesink i Geert F. Versteeg. "Precipitation of metal sulphides using gaseous hydrogen sulphide: mathematical modelling". Chemical Engineering Science 59, nr 3 (luty 2004): 567–79. http://dx.doi.org/10.1016/j.ces.2003.11.006.
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Meyer, Edson, Asanda Bede, Nyengerai Zingwe i Raymond Taziwa. "Metal Sulphides and Their Carbon Supported Composites as Platinum-Free Counter Electrodes in Dye-Sensitized Solar Cells: A Review". Materials 12, nr 12 (20.06.2019): 1980. http://dx.doi.org/10.3390/ma12121980.
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Energy sufficiency is a critical requirement for the economic prosperity of modern countries. Efficient harnessing of solar energy using technologies such as the dye-sensitized solar cell could solve the energy problem which persistently plagues developing countries. Despite having a simple operational procedure and modest power conversion efficiency of 13.8%, the dye-sensitized solar cell consists of an expensive platinum counter electrode which makes commercial success futile. Thus, this review intends to establish the progress researchers have attained in the development of sulphide based counter electrodes as alternatives to platinum, thereby lowering cost of production. Metallic sulphides are good electrocatalysts and cheap, hence, they possess the necessary requirements for effective functional counter electrodes. Furthermore, ternary metallic sulphides are known to exhibit higher efficiencies stemming from the synergistic effect produced by the co-existence of two metal ions in a crystal structure, which is believed to induce greater catalytic capability. Incorporation of metallic sulphides with carbon materials, which are exceptional electrical conductors, could potentially produce more efficient counter electrodes. In that regard, this review seeks to establish the effect recently developed composite counter electrodes comprising metallic sulphides and carbon-based materials have induced on the functionality of the counter electrode (CE).
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Oszczepalski, Sławomir, i Andrzej Chmielewski. "Mineralization of the Zechstein Lower Anhydrite in the Fore-Sudetic Monocline". Biuletyn Państwowego Instytutu Geologicznego 472, nr 472 (20.11.2018): 135–54. http://dx.doi.org/10.5604/01.3001.0012.7116.
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The paper presents the characteristics of ore mineralization of the Lower Anhydrite in the Fore-Sudetic Monocline. Both reduced and oxidized (Rote Fäule) rocks have been investigated. Reduced anhydrites are characterized by significant variability of metal concentrations and sulphide minerals. The most intensely mineralized anhydrites occur above the oxidized bottom part of the Lower Anhydrite. Mineralization in this part is dominated by copper sulphides (chalcocite, digenite, covellite, bornite and chalcopyrite) which are accompanied by galena and sphalerite. Further away from the oxidized zone, zinc and lead sulphides predominate over copper sulphides, and pyrite mineralization is also observed. Complex intergrowths and replacement textures of sulphides, as well as intergrowths of the ore minerals with sulphates and carbonates are considered to have formed after lithification of the enclosing sediments, and indicate that the original associations of sulphides were overprinted by superimposed later mineralization. Oxidized anhydrites generally have no significant concentrations of metals like Cu, Pb and Zn. The relict mineralization there is represented by remnants of tiny grains of copper sulphides (mainly covellite, digenite and chalcocite) and pyrite, profoundly altered as a result of their partial replacement by hematite. This mineralization present in the oxidized anhydrites indicates that hematite emplacement overlapped deposition of the original sulphides and extended oxidation up into the Lower Anhydrite. Position of the reduced and oxidized areas of anhydrites enriched in metals indicates centres of the most intense activity of the ascending mineralizing fluids.
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Danielewski, Marek. "Diffusion in Transition Metal Sulphides". Defect and Diffusion Forum 66-69 (styczeń 1991): 257–58. http://dx.doi.org/10.4028/www.scientific.net/ddf.66-69.257.
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Semenov, Victor N., i Alexander V. Naumov. "Interaction of metal sulphides in films deposited from solutions of thiourea coordination compounds. Review". Kondensirovannye sredy i mezhfaznye granitsy = Condensed Matter and Interphases 23, nr 3 (17.08.2021): 337–52. http://dx.doi.org/10.17308/kcmf.2021.23/3525.
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Metal sulphides are highly important for the technology of semiconductor film materials. The potential of these compounds has not been exhausted yet when it comes to creating optoelectronic devices, solar cells, and luminescent devices based on them. The goal of this work was to determine the nature of interaction of sulphides in polycrystalline layers of CdS–MemSn, where Me are metals of groups I–VII of the periodic table. Cadmium sulphide was chosen as the common component of all studied systems due to the great photoelectric and luminescent properties of this well-studied material.It was shown that using aerosol spray pyrolysis of the solutions of thiourea complexes, we can obtain solid solutions and chemical compounds of CdS–MеmSn at temperatures not exceeding 500 °C. The main electric, optical, and luminescent properties of the layers were described.It was established that the use of aerosol spray pyrolysis of the solutions of thiourea coordination compounds allows significantly expanding the areas of solubility during the formation of solid sulphide solutions. The specific character of solid-phase interaction and nonequilibrium of the processes occurring during the deposition of layers allow avoiding structural incompatibility of the components expressed in the form of typical factors, such as the non-uniformity of crystal structure, differences in the chemical nature of the components, and discrepancies in sizes of substituting/penetrating atoms.Under such conditions of deposition of films (the lower threshold of deposition temperatures is determined by the temperature of decomposition of the most thermally stable thiourea coordination compound and does not exceed 250 °С), the solid-phase interactions of most sulphides cannot be achieved. Therefore, the interaction occurs at the moment of thermal destruction of complex compounds due to the emerging valence opportunities of their structural fragments
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Glukhov, A. N. "Base metal mineralization of the Kolyma terrain in Northeast Russia: Overview and genetic classification". LITHOSPHERE (Russia) 19, nr 5 (23.11.2019): 717–30. http://dx.doi.org/10.24930/1681-9004-2019-19-5-717-730.
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Research subject. The Prikolyma terrain located in the Northeastern part ofRussia constitutes a long-lived Precambrian thrust-faulted structure hosting numerous Cu, Pb and Zn deposits of different types.Materials and methods. The mineralization of the terrain was examined during a course of research and exploration works over the 2007–2012. The rock geochemistry was studied using ICP-OES analysis at the Stuart Geochemistry and Essay laboratory (Moscow). The microprobe analysis of minerals was carried out at the facilities of the Far Eastern Branch of the Russian Academy of Sciences (Magadan) using a Camebax X-ray microanalyzer. The isotopic ratios of sulphur in sulphides were measured using a Finnigan MAT 253 isotope mass spectrometer.Results. The porphyry-copper deposit Nevidimka is represented by skarns and sulphide-quartz stockworks embedded in porphyry granites. The vein deposits Opyt and Glukhoye constitute sulphide-carbonate-quartz veins, the composition of which corresponds to copper-polymetallic ores of the peripheral parts of the copper-porphyry formation. These deposits feature a similar geochemistry and composition of sulphides and sulphur isotopes, which is characteristic of the Riphean complexes of the Prikolyma terrain. The stratiform Pb-Zn veins Nadezhda-3 and Khaya enclosed in Proterozoic dolomites represent parallel-bedding disseminated sulphides. The composition of these ores indicates their diagenetic origin. Tne stratiform copper deposit Oroyok is embedded in Proterozoic shales and can be referred to sediment-hosted copper deposits of a transgressive type.Conclusions. The diversity of Cu-Pb-Zn mineralization types in the Prikolyma terrain is established to have resulted from multiple cyclic changes of the geodynamic ore formation regime. During each such cycle, syngenetic mineralization was followed first by epigenetic and then by vein mineralization. The mobile, thrust-faulted structure caused repeated rejuvenation of ores, which inherited the geochemical features of hosting rocks.
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Labaj, Ivan, Darina Ondrušová, Andrej Dubec, Mariana Pajtášová, Marcel Kohutiar i Beata Pecušová. "Study of new rubber to steel adhesive systems based on Co(II) and Cu(II) sulphides coats". MATEC Web of Conferences 157 (2018): 07004. http://dx.doi.org/10.1051/matecconf/201815707004.
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The presented paper deals with the preparation of new rubber to steel adhesive systems using the steel surface treatment with deposition of adhesive coats based on Co(II) and Cu(II) sulphides. Efficiency of new prepared adhesive systems containing Co(II) and Cu(II) sulphides has been compared with the efficiency of double layer adhesive system commonly used in industry. The chemical composition of prepared adhesive systems was determined using the EDX analysis. Scanning Electron Microscopy (SEM) was used for study of topography and microstructure of prepared rubber to steel adhesive systems (Co(II), Cu(II) sulphide, double layer adhesive system). For determination of adhesion strength between rubber blends and metal pieces with various adhesive systems deposited on these pieces, the test according to ASTM D429 standard relating to Rubber to metal adhesion, method A was used. For all test samples, the same type of rubber blend and the same curing conditions have been used.
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Veeken, A. H. M., i W. H. Rulkens. "Innovative developments in the selective removal and reuse of heavy metals from wastewaters". Water Science and Technology 47, nr 10 (1.05.2003): 9–16. http://dx.doi.org/10.2166/wst.2003.0525.
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Sulphide precipitation of heavy metal containing wastewaters results in low effluent concentrations. However, sulphide precipitation is not widely applied in practice because the dosing of sulphide cannot adequately be controlled. A new process was developed where the combination of a sulphide-selective electrode (pS-electrode) and pH electrode controls the sulphide addition. Precipitation experiments were performed on a laboratory-scale in batch and continuous reactor systems with synthetic wastewaters containing Cd, Cu, Ni, Pb or Zn. The response of the pS-electrode during precipitation was unique for each heavy metal and was directly related to the solubility product of the corresponding metal sulphide. The metals were removed to levels <0.05 mg.l-1 at pH 6.0 by sulphide precipitation while maintaining a total sulphide concentration <0.02 mg.l-1. By the control of pS at different levels and keeping the pH constant at 6.0, the metals in solutions of both Cu and Zn could be precipitated selectively from solution in a batch and continuous reactors. The use of a membrane reactor in combination with control of pH and pS offers a simple, cheap, efficient and sustainable technique with respect to obtaining very low effluent concentrations and selective removal of metals as pure metal sulphides which can be reused.
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Van Dover, Cindy Lee. "Mining seafloor massive sulphides and biodiversity: what is at risk?" ICES Journal of Marine Science 68, nr 2 (30.06.2010): 341–48. http://dx.doi.org/10.1093/icesjms/fsq086.
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Abstract Van Dover, C. L. 2011. Mining seafloor massive sulphides and biodiversity: what is at risk? – ICES Journal of Marine Science, 68: 341–348. Scientific exploration of the deep sea in the late 1970s led to the discovery of seafloor massive sulphides at hydrothermal vents. More recently, sulphide deposits containing high grades of ore have been discovered in the southwest Pacific. In addition to metal-rich ores, hydrothermal vents host ecosystems based on microbial chemoautotrophic primary production, with endemic invertebrate species adapted in special ways to the vent environment. Although there has been considerable effort to study the biology and ecology of vent systems in the decades since these systems were first discovered, there has been limited attention paid to conservation issues. Three priority recommendations for conservation science at hydrothermal vent settings are identified here: (i) determine the natural conservation units for key species with differing life histories; (ii) identify a set of first principles for the design of preservation reference areas and conservation areas; (iii) develop and test methods for effective mitigation and restoration to enhance the recovery of biodiversity in sulphide systems that may be subject to open-cut mining.
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Kotzé, E., i C. Gauert. "PGE distribution in the chromitite layers at Eastern Chrome Mine, Eastern Bushveld Complex, South Africa: A descriptive study with comparison of EPMA and LA-ICP-MS methods for detection of trace PGE in base metal sulphides". South African Journal of Geology 123, nr 4 (26.10.2020): 551–72. http://dx.doi.org/10.25131/sajg.123.0033.
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Abstract A descriptive petrographic study was carried out on the chromitites (LG-6 to UG-3a) of a single borehole from the Winterveld Chrome Mine, Eastern BC, along with analysis by both EPMA and LA-ICP-MS of the PGE contents of base metal sulphides (BMS) found within these layers. EPMA measurements were optimized to measure trace amounts of PGE by increased probe current and counting time, yielding very low detection limits for this method (12 to 38 ppm). However, analytical error proved to be very high (over ~30%) in samples that showed PGE values below 100 ppm. Also, the possibility of interference on PGE spectra by other elements, especially on Rh, is high. Therefore, these measurements can only be considered semi-quantitative indicators of elemental PGE concentration. Our findings confirmed that pentlandite of the BC chromitites contains Pd and Rh, probably in solid solution. Pt was found in discrete minerals (braggite, cooperite) throughout the sequence, and Ru, Ir and Os were found as early-stage minerals such as laurite, associated with chromite rather than sulphide. The PPGE increase upwards in the chromitite layers relative to the IPGE. An immiscible sulphide phase contributed to collection of the PGE in the chromitites of the MG-4 and above. The chromitites of the LG-6 to MG-1 show less evidence of hosting an immiscible sulphide phase, and pentlandite of these layers does not appear to host Rh, although Pd was found. Although this borehole is located only 1.5 km away from the centre of the Steelpoort Fault Zone, a possible feeder zone for the BC, large-scale disruption of the chromitite layers was not observed. An intrusive pegmatoidal pyroxenite was found to occur beneath the LG-6, and contained PGE-bearing sulphides, although the origin of this mineralization is most likely from the LG-6 chromitite itself. A sulphide vein occurring in silicate was also analysed and was found to be PGE-deficient compared to the sulphides of the chromitite layers.
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Mikulski, Stanisław Z., Katarzyna Sadłowska, Janina Wiszniewska i Rafał Małek. "Vanadium and Cobalt Occurrence in the Fe-Ti-V Oxide Deposits Related to Mesoproterozoic AMCG Complex in NE Poland". Applied Sciences 12, nr 12 (20.06.2022): 6277. http://dx.doi.org/10.3390/app12126277.
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On the basis of geochemical whole-rock and mineralogical point analyses, the concentrations of V and Co were determined in magnetite-ilmenite oxide ores, associated with sulphides, at the Krzemianka and Udryn deposits in the Mesoproterozoic Suwałki Anorthosite Massif (SAM) in NE Poland. EPMA analyses showed that the main carrier of vanadium was magnetite (mean = 0.42 wt%) and, to a lesser extent, ilmenite (mean = 0.14 wt%) and minor Al-spinels (mean = 0.04 wt%). In turn, cobalt was found mainly in the form of isomorphic substitutions in magmatic sulphides such as pentlandite (mean = 4.41 wt% Co), pyrrhotite (mean = 0.16 wt%), and chalcopyrite (mean = 0.11 wt%). Moreover, Co-enrichments were also recognized in the secondary sulphides, such as pyrite and bravoite, replacing pyrrhotite (means = 1.6 and 2.7 wt% Co, respectively), and in the form of different thiospinels ((Fe, Ni) (Co, Ni)2S4), mainly siegenite (mean = 22.0 wt% Co), replacing pyrrhotite and pentlandite. Vanadium cations were substituted in Fe, Ti oxide minerals in place of Fe+3 cations, and in the case of cobalt, Fe+2 cations were substituted in sulphides and thiospinels. Vanadium and cobalt showed high Person’s correlation coefficients (r = 0.70), indicating their close spatial coexistence and a common source, which was parental anorthosite-norite magma of the SAM suites. The common magma genesis of magnetite-ilmenite and sulphide mineralization was also confirmed by the very similar shapes of the curves of REE content in the oxide-sulphide ores in relation to chondrite, in which negative Eu anomalies and positive Sm anomalies are clearly visible. Although the average contents of vanadium and cobalt were low (arithmetic means = 960 ppm, and 122 ppm, respectively), the resources of these metals were estimated to be large due to the enormous reserves of magnetite-ilmenite ores hosted by the SAM. However, the Fe-Ti-V ores associated with Fe, Ni, Co, and Cu sulphides were considered to be sub-economic because of their depth of occurrence (mainly 1.0 km below the surface level); their metal contents, which were usually too low; and additionally the fact that the location is in a highly environmentally protected landscape and lake area.
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Vokes, F. M., i J. R. Craig. "Post-recrystallisation mobilisation phenomena in metamorphosed stratabound sulphide ores". Mineralogical Magazine 57, nr 386 (marzec 1993): 19–28. http://dx.doi.org/10.1180/minmag.1993.057.386.03.
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AbstractMetamorphosed stratabound iron- and base-metal sulphide deposits often exhibit microtextures in which fractures in cataclastically-deformed pyrite porphyroblasts are filled with matrix sulphides; chalcopyrite, sphalerite, pyrrhotite or galena. Discussions of such textures have mostly centred on whether solid-phase or fluid-phase mechanisms were responsible for the movement of the matrix sulphides.The small Zn-Cu sulphide body at Gressli, in the central Norwegian Caledonides, shows these textural features to an extreme degree. Both chalcopyrite and sphalerite show heavy replacive relations to the cataclastically deformed metablastic pyrite, along fracture walls and grain boundaries. They also occur injected along the opened-up triple junctions of foam-textured pyrite. In addition, parts of the ore show patchy quartz with clear replacive relationship to all three sulphides, a feature not often reported from such ores. Such textures can be interpreted to support a mobilisation sequence chalcopyrite-sphalerite-quartz within the Gressli ore. Their extent and degree of development indicate that fluid-phase mobilisation of the three minerals must have played a dominant role. Chalcopyrite and sphalerite are most likely derived from within the ore-mass itself; an external source for the SiO2 seems most probable, in the form of metahydrothermal solutions moving along retrograde shear zones at or near ore-walls.
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Vandentop, G. J., M. A. Karolewski i Ronald G. Cavell. "Secondary ion mass spectra of metal sulphides". International Journal of Mass Spectrometry and Ion Processes 89, nr 2-3 (styczeń 1989): 319–42. http://dx.doi.org/10.1016/0168-1176(89)83067-8.
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Lacroix, M., N. Boutarfa, C. Guillard, M. Vrinat i M. Breysse. "Hydrogenating properties of unsupported transition metal sulphides". Journal of Catalysis 120, nr 2 (grudzień 1989): 473–77. http://dx.doi.org/10.1016/0021-9517(89)90287-x.
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Mrowec, S., i K. Hashimoto. "Chemical diffusion in non-stoichiometric metal sulphides". Journal of Materials Science 30, nr 19 (październik 1995): 4801–16. http://dx.doi.org/10.1007/bf01154488.
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Luptáková, Alena, Stefano Ubaldini, Eva Mačingová i Ingrida Kotuličová. "Study of Precipitating Methods for Elimination of Heavy Metals from Acid Mine Drainage". Nova Biotechnologica et Chimica 11, nr 2 (1.12.2012): 133–38. http://dx.doi.org/10.2478/v10296-012-0015-y.
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Abstract The submitted paper deals with the study of combination of chemical and biological-chemical methods for the heavy metals elimination from the acid mine drainage. The experiments were carried out at the laboratory scale using a synthetic solution with similar properties to the real sample of acid mine drainage, originating from the zinc mine located in Tùnel Kingsmill outflow of the Rio Yaulì (district of Yauli - Perù). The successive repetition of the metal precipitations as hydroxides (chemical method) and sulphides (biological-chemical method) at the various acid mine drainage pH was the basis of the examined processes. For the hydrogen sulphide production the sulphate-reducing bacteria of genus Desulfovibrio were used. Results confirmed the precipitation of Fe, As, Al and Mn in the hydroxide form; Cu and Zn in the form of sulphides. For the selective removal of Cu, Zn, Al and Mn the excellent results were received. Selective precipitation of Fe and As was not so successful since the co-precipitation of Fe and As was later determined as a main mechanism of the precipitate forming.
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Bacsó, Zoltán. "The Brehov volcanogenic and stratabound base metal and gold deposit (Eastern Slovakia): Position and genetic relations in the Internal Carpathian–Alpine Cenozoic metallogenetic belt". Mineralia Slovaca 55, nr 1 (31.07.2023): 27–52. http://dx.doi.org/10.56623/ms.2023.55.1.3.
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The Brehov ore deposit, near the village of Brehov, is located in the East Slovakian Basin 15 km south-east of the Trebišov town. A progressive development of Middle Badenian to Middle Sarmatian sedimentation and volcanism in the Brehov hydrothermally mineralized area is manifested in the article. The volcanogenic, stratabound, polymetallic (Zn, Pb, Cu) and gold sulphide deposit within the Brehov–Sirník interpreted resurgent caldera occurs in the volcanosedimentary sequence. Mineralization in the deposit, consisting of the fine-grained aggregate of sulphides, is interpreted to be of shallow water origin. It is placed mostly in the rhyodacite volcaniclastics and partly in calcareous claystone, altered and brecciated. Three types of ores – the stringer (keiko), yellow and black ore – were distinguished near the Brehov village on the basis of ore composition, being formed by successive mineralization stages. The stringer ore, consisting of the sulphide minerals, dominates in the quartz-dioritic (siliceous) rocks. The yellow ore is represented primarily by pyrite, but contains also minor chalcopyrite and quartz. The black ore is an intimate mixture of sphalerite, galena, sometimes barite and minor pyrite and chalcopyrite. Tetrahedrite and marcasite occur sporadically. The ore in all cases is fine-grained. The ore bodies are almost everywhere enclosed by clay, composed of montmorillonite, sericite and chlorite. The ore bearing fluids were probably colloids of hydrothermal origin. Textures are considered to indicate that the colloids replaced the country rocks, rather than merely filled open spaces in the rhyodacite pyroclastics and epiclastics. Despite the precious metals (mostly gold) are economically important commodity in many Kuroko type deposits, in the Brehov ore deposit they occur in volumetrically minor amounts. Visible gold is present as inclusions of native gold in major sulphide minerals, whereas silver occurs in Ag-sulphides and sulphosalts, e.g. tetrahedrite and ferberite.
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Porzionato, Natalia, Mariangeles Mellota, Roberto Candal i Gustavo Curutchet. "Acid Drainage and Metal Bioleaching by Redox Potencial Changes in Heavy Polluted Fluvial Sediments". Advanced Materials Research 825 (październik 2013): 496–99. http://dx.doi.org/10.4028/www.scientific.net/amr.825.496.
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Sediments from polluted urban streams act as a sink of contaminants. The high content of organic matter and sulphides makes the system appropriate for binding heavy metals. However, changes in the redox potential leads to processes in which sediments acts like a low sulphidic ore in an oxidizing environment, and could generate acid drainages. Human and not human disturbances of the sediments could derive in its oxidation catalyzed by sulphur oxidizing bacteria (SOB). This process leads to acidification and metal release. In this study we analyze the acidification potential of anaerobic sediments of polluted streams near Buenos Aires with static and kinetic methods. The results remark the necessity to consider this process before any sediment management action.
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van den Berg, Gerard A., J. P. Gustav Loch, John J. G. Zwolsman i Lambertus M. van der Heijdt. "Non-steady state behaviour of heavy metals in contaminated freshwater sediments". Water Science and Technology 37, nr 6-7 (1.03.1998): 39–46. http://dx.doi.org/10.2166/wst.1998.0733.
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The behaviour of heavy metals has been investigated in contaminated sediments of the river Meuse, The Netherlands. Due to temporal changes in temperature and degradability of organic matter, the depths of the redox boundaries fluctuate. This contributes to a non-steady state. As a result of oxidation processes, a distinct peak in heavy metal concentrations in pore water is measured at the sediment-water interface. Because the studied anoxic sediments contain low levels of sulphide, other solid phases are expected to be of importance in the binding of heavy metals. Furthermore, heterogeneity of the sediment and complexation with dissolved organic compounds may result in supersaturation of the anoxic pore waters with respect to discrete heavy metal sulphides, thus influencing heavy metal mobility. Calculations using concentration gradients of heavy metals indicate that diffusive fluxes between the sediment and the surface water contribute to concentrations in the surface water, although significant effects may be confined to specific locations.
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Biegger, Felix, Christoph Rameshan, Alexander K. Opitz, Julian Noll, Thomas Haunold, Heinrich Lang i Sven Barth. "Thioether functionalised gallium and indium alkoxides in materials synthesis". New Journal of Chemistry 40, nr 8 (2016): 6962–69. http://dx.doi.org/10.1039/c6nj00402d.
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Powell, Anthony V., T. Erinc Engin, Paz Vaqueiro i Steve Hull. "Simultaneous diffraction and resistance measurements of metal sulphides". Journal of Physics and Chemistry of Solids 68, nr 5-6 (maj 2007): 1052–56. http://dx.doi.org/10.1016/j.jpcs.2006.12.018.
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Talapatra, A. K., R. C. Talukdar i P. K. De. "Electrochemical technique for exploration of base metal sulphides". Journal of Geochemical Exploration 25, nr 3 (maj 1986): 389–96. http://dx.doi.org/10.1016/0375-6742(86)90086-5.
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Divigalpitiya, W. M. R., R. F. Frindt i S. R. Morrison. "Spread films of single molecular transition-metal sulphides". Applied Surface Science 48-49 (styczeń 1991): 572–75. http://dx.doi.org/10.1016/0169-4332(91)90392-w.
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Kadu, Rahul, Vineeta Pillai, Amrit V. i Vinay K. Singh. "Synthesis and spectral characterization of bimetallic metallomacrocyclic structures [MII2-μ2-bis-{(κ2S,S-S2CN(R)C6H4)2O}] (M = Ni/Zn/Cd): density functional theory and host–guest reactivity studies". RSC Advances 5, nr 129 (2015): 106688–99. http://dx.doi.org/10.1039/c5ra22175g.
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Jowett, E. Craig, Andrzej Rydzewsk i Robin J. Jowett. "The Kupferschiefer Cu–Ag ore deposits in Poland: a re-appraisal of the evidence of their origin and presentation of a new genetic model". Canadian Journal of Earth Sciences 24, nr 10 (1.10.1987): 2016–37. http://dx.doi.org/10.1139/e87-192.
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The Kupferschiefer stratiform copper deposits in central Europe have long been considered a classic example of syngenetic mineralization. However, metal zoning and host-rock relationships determined during exploration around the recently discovered Lubin district orebodies in southwest Poland suggest that the ore may instead be late diagenetic. The mineralization occurs as thin, extensive blankets of sulphides in the pyritic, organic-rich basal units of the Late Permian Zechstein restricted marine sequence and in the eolian Weissliegendes sandstone at the top of the Early Permian Rotliegendes continental rift sequence of bimodal volcanic rocks and redbeds. It is directly underlain and controlled by irregular, oval zones of Rote Fäule (RF), a barren oxidized and reddened portion of the normally dark grey, pyritic basal Zechstein rocks. In plan view, the metals occur as successive belts enriched in copper (+ silver), lead, and zinc, which developed laterally from and encircle the RF zones. The ore transgresses the depositional strike of the basal Zechstein and can occur in any sedimetary facies. In section, the ore cuts across sedimentary layering from the Zechstein limestone down through the Kupferschiefer shale (Ks) into the sand stone below. Framboidal, presumably very early diagenetic, pyrite is the dominant sulphide above and lateral to the ore zones; over most of the basin, the Ks is pyritic and not anomalously high in metals compared with similar shale elsewhere. In the ore bodies, Cu, Ag, Pb, and Zn are significantly above the typical background contents, implying that these metals have been introduced. Metal contents in the RF are within the range of background contents of the Ks, suggesting that the metal source is external to the Ks. The RF–copper zones are coincident with underlying buried basement highs and occur only above Rotliegendes sediments with underlying volcanic rocks, indicating a possible genetic connection. The metal zones generally dip away from the highs toward the basin centres, suggesting convective, rather than throughgoing, fluid flow. Sulphides, as disseminations and streaks, commonly replace earlier calcite cement and lenses, lithic fragments, and quartz grains. Horizon tal and vertical dilatant veinlets of calcite and copper sulphides appear to have formed after lithification and contemporaneously with the disseminations and streaks, but not by remobilization of existing sulphides. The veinlet orientations are believed to be Kimmerian age (mid-Triassic to Late Jurassic), and the orebodies are cut and displaced, but not remobilized, by fractures and dikes of inferred Alpine (Cretaceous) age. Published sulphur-isotope ratios indicate that the copper sulphides were not formed in isotopic equilibrium with the pyrite, but adequate sulphur- and lead-isotope information on the ore deposits is not available to support an early or late diagenetic timing. The paleomagnetic age of the stable chemical remanence of the RF is Middle Triassic, supporting a late diagenetic origin of the ore coincident with a second rifting event. On account of these asso ciations and controls, it is proposed that the RF–ore systems were formed by converting Na–Ca–CI Rotliegendes formational brines. The metals were leached from the Rotliegendes volcanic detritus and carried in solution as chloride complexes through the redbeds up the flanks of the buried basement highs to the reduced pyritic Ks above. The fluids oxidized the original Ks pyrite to form the Rote Fäule, and the ore sulphides were precipitated on the far side of this subhorizontal oxidation–reduction front. This late diagenetic mineralizing event likely occurred during the Triassic, when rapid burial and increased heat flow, associated with the opening of the Tethys ocean to the south, generated natural gases and vertical fractures in the Ks and increased convective fluid velocities in the Rotliegendes basins.
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Abraitis, P. K., R. A. D. Pattrick, G. H. Kelsall i D. J. Vaughan. "Acid leaching and dissolution of major sulphide ore minerals: processes and galvanic effects in complex systems". Mineralogical Magazine 68, nr 2 (kwiecień 2004): 343–51. http://dx.doi.org/10.1180/0026461046820191.
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AbstractThe kinetics and mechanisms of dissolution of the major base metal sulphide minerals, pyrite, chalcopyrite, galena and sphalerite in acidic (chloride) media have been investigated. Minerals were ground in air, then dissolved in air-equilibrated solutions at pH 2.5, while monitoring the redox potential. Solution samples were analysed by ICP-AES and HPLC, and surfaces of residual sulphides analysed using XPS. Dissolution of aerial oxidation products on pyrite particles in the first 15 min apparently led to a sulphur-rich surface, and was followed by slower dissolution of pyrite itself, driven by oxygen reduction, and resulting in net production of protons. Chalcopyrite dissolution resulted in a Cu, S-rich (near) surface layer, accompanied by net consumption of protons. Apparently incongruent dissolution of galena and sphalerite may reflect the formation of elemental S at the surface. The rates of dissolution of chalcopyrite, galena and sphalerite in the presence of pyrite were determined, respectively, as 18, 31 and 1.5 times more rapid than in single-mineral experiments. These data were consistent with galvanically-promoted mineral oxidation of the other sulphides in the presence of pyrite. In the case of galena, the experimental data suggested extensive release of Pb ions and development of a sulphur-rich surface during galvanically-promoted dissolution.
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Zheng, G. D., T. B. Chen, D. Gao i W. Luo. "Dynamic of lead speciation in sewage sludge composting". Water Science and Technology 50, nr 9 (1.11.2004): 75–82. http://dx.doi.org/10.2166/wst.2004.0539.
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A large-scale sewage sludge composting experiment was conducted to develop an understanding of changes that occur to Pb chemical speciation, distribution and bio-availability during the course of composting. The four-stage Tessier sequential extraction method was employed to investigate the dynamics of heavy metal Pb speciation (exchangeable, bound to carbonates, bound to Fe-Mn oxides, bound to organic matter and sulphides, residual) during the course of sewage sludge composting. The concentrations of the total Pb and the five Pb fractions concentrations were increased during the whole stage of compost. However, the percentages of Pb distribution with respect to total Pb were changed in the following manner: exchangeable, bound to Fe-Mn oxides and bound to carbonates Pb with respect to total Pb were increased, while the percentages of bound to organic matter and sulphides, and residual Pb with respect to total Pb were decreased during composting. The data showed that the quantity of Pb in the less toxic portion, such as consisting of organic matter and sulphides bound and residual Pb, was increased, and that the contamination and bio-availability of heavy metal Pb in sewage sludge was reduced during the composting process.
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Cwalina, Beata, Weronika Dec, Wojciech Simka, Joanna Michalska i Marzena Jaworska-Kik. "Biofilm Formation on NiTi Surface by Different Strains of Sulphate Reducing Bacteria (Desulfovibrio desulfuricans)". Solid State Phenomena 227 (styczeń 2015): 302–5. http://dx.doi.org/10.4028/www.scientific.net/ssp.227.302.
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Bacteria of Desulfovibrio genus belong to group of widespread sulphate-reducing bacteria (SRB). D. desulfuricans is considered one among many bacterial species involved in microbiologically influenced corrosion (MIC) of metals, mainly of stainless steels and other alloys. SRB can produce gaseous hydrogen sulphide. This gas is released into the environment leading to formation of metal sulphides that significantly influence electrochemical processes and ultimately enhance the corrosion of materials. Biofilms formed by these bacteria are especially harmful for highly alloyed steels and many alloys. The aim of this work was to compare the character of growth and biofilm formation by three strains of D. desulfuricans (standard soil strain DSM and two wild intestinal strains: DV/A and DV/B) on the surface of NiTi alloy.
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McGlynn, Shawn E., Isik Kanik i Michael J. Russell. "Peptide and RNA contributions to iron–sulphur chemical gardens as life's first inorganic compartments, catalysts, capacitors and condensers". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 370, nr 1969 (28.06.2012): 3007–22. http://dx.doi.org/10.1098/rsta.2011.0211.
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Hydrothermal chimneys and compartments comprising transition metal sulphides and associated minerals have been proposed as likely locations for the beginnings of life. In laboratory simulations of off-axis alkaline springs, it is shown that the interaction of a simulated alkaline sulphide-bearing submarine vent solution with a primeval anoxic iron-bearing ocean leads to the formation of chimney structures reminiscent of chemical gardens. These chimneys display periodicity in their deposition and exhibit diverse morphologies and mineralogies, affording the possibilities of catalysis and molecular sequestration. The addition of peptides and RNA to the alkaline solution modifies the elemental stoichiometry of the chimneys—perhaps indicating the very initial stage of the organic takeover on the way to living cells by charged organic polymers potentially synthesized in this same environment.
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Thorpe, R. I., M. D. Goodz, I. R. Jonasson i J. Blenkinsop. "Lead-isotope study of mineralization in the Cobalt district, Ontario". Canadian Journal of Earth Sciences 23, nr 10 (1.10.1986): 1568–75. http://dx.doi.org/10.1139/e86-147.
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Twenty-seven lead-isotope analyses for galena specimens from 14 localities in the Cobalt district represent sulphide-rich interflow sedimentary units in the Archean volcanic sequence, mineralized zones, fracture fillings, and local sulphide concentrations in the Cobalt Group (Proterozoic) sedimentary rocks, and vein-filling and breccia-cementing sulphides from within and near silver–arsenide veins. The analyses define a very homogeneous composition, averaging 206Pb/204Pb = 14.732, 2O7Pb/204Pb = 15.114, and 208Pb/204Pb = 34.301, for lead from these different geological settings. This result is in agreement with textural observations indicating a late paragenetic position for galena in the different settings mentioned. The model age for this lead is in general accord with the U–Pb age obtained in a study by Andrews et al. for a Nipissing diabase sheet at Gowganda.About one third of the galena specimens are interpreted by a two-stage evolution model to have formed or been remobilized during an event in the time range 1650–1945 Ma. The timing and character of this event are not clearly defined. The radiogenic composition of a specimen from the Pan Silver property is comparable to radiogenic values reported by Thorpe and suggests a young galena-forming event in the area.The lead-isotope data are permissive evidence for a genetic link between the Nipissing diabase sheets and mineralization of a variety of types in the Cobalt district. The metal source is not clearly indicated, but one analysis for Archean interflow sulphides suggests than an Archean source is unlikely for the lead in the silver–arsenide veins and other mineralized zones.
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Coghill, Bronwen M., i Allan H. Wilson. "Platinum-group minerals in the Selukwe Subchamber, Great Dyke, Zimbabwe: implications for PGE collection mechanisms and post-formational redistribution". Mineralogical Magazine 57, nr 389 (grudzień 1993): 613–33. http://dx.doi.org/10.1180/minmag.1993.057.389.06.
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AbstractThis paper presents the results of microprobe investigations of the Platinum-Group Elements (PGE) of the Selukwe Subchamber, Great Dyke, Zimbabwe. The PGE are associated with base metal sulphides in the uppermost pyroxenites of the Ultramafic Sequence of the Great Dyke. The following minerals have been indentified: bismuthotellurides (moncheite, maslovite, michenerite, kotulskite and polarite); arsenides (sperrylite); and sulphides and sulpharsenides (cooperite, laurite, braggite and hollingworthite). Platinum Group Minerals (PGM) occur in three distinct textural environments: (1) at the boundary of sulphides and silicates/hydrosilicates, (2) entirely enclosed within sulphides, and (3) entirely enclosed within silicate or hydrosilicate minerals. The stratigraphic distribution, environments and textures of the PGM have important genetic implications, and cannot be explained by a single process. A multi-process model for the petrogenesis of the PGE mineralisation in terms of complexation and intermediate compound formation is proposed. The primary mineralising events were due to orthomagmatic processes, but the observed textures are the result of microscale remobilisation of PGM components by trapped interstitial fluids (bydromagmatic processes).
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Hobbs, D., i J. Hafner. "Magnetism and magneto-structural effects in transition-metal sulphides". Journal of Physics: Condensed Matter 11, nr 42 (5.10.1999): 8197–222. http://dx.doi.org/10.1088/0953-8984/11/42/303.
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Kolb, M. A., W. F. Maier i K. Stöwe. "High-throughput syntheses of nano-scaled mixed metal sulphides". Catalysis Today 159, nr 1 (styczeń 2011): 64–73. http://dx.doi.org/10.1016/j.cattod.2010.07.010.
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Dovorogwa, Hamlton, i Kevin Harding. "Exploring the Use of Tobacco Waste as a Metal Ion Adsorbent and Substrate for Sulphate-Reducing Bacteria during the Treatment of Acid Mine Drainage". Sustainability 14, nr 21 (2.11.2022): 14333. http://dx.doi.org/10.3390/su142114333.
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Treatment of acid mine drainage (AMD) was successfully demonstrated using tobacco waste (dust and stem) as a metal cation adsorbent, pH modifier and carbon source for sulphate-reducing bacteria (SRB). Synthetic and industrial AMD wastewaters were used in batch adsorption and SRB facilitated bioremediation experiments. Up to absorbent loading of 80 g/L, metal removal increased. However, increases above 160 g/L did not offer a proportional increase. At an adsorbent loading of 80 g/L, the highest metal removals of 38, 41, 31 and 43% for iron, nickel, copper and zinc respectively were achieved. The iron data fitted well to the Langmuir adsorption isotherm while the Sips adsorption isotherm better-described nickel, copper and zinc adsorption to tobacco waste. SRBs used were able to use tobacco waste as a carbon source while reducing sulphates to metal sulphides in acid mine drainage. In the presence of SRBs, metal removals by both adsorption and sulphide precipitation were 95, 97, 70 and 93% for iron, nickel, copper and zinc, respectively. Copper, however, demonstrated lower removal yields in both adsorption and bioremediation. Bioremediation improved acid mine drainage pH by 2.05 units. The exponential decay function could model both the metal and sulphate removal perfectly. It was concluded that tobacco waste can be confidently used as an adsorbent and carbon source for sulphate-reducing bacteria while facilitating AMD biological treatment.
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Pan, Yuanming, i Michael E. Fleet. "Mineralogy and genesis of calc-silicates associated with Archean volcanogenic massive sulphide deposits at the Manitouwadge mining camp, Ontario". Canadian Journal of Earth Sciences 29, nr 7 (1.07.1992): 1375–88. http://dx.doi.org/10.1139/e92-111.
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Skarn-like calc-silicate rocks are reported in spatial association with the Archean Cu–Zn–Ag massive sulphide deposits at the Manitouwadge mining camp, Ontario. Calc-silicates in the footwall of the Willroy mine occur as matrix to breccia fragments of garnetiferous quartzo-feldspathic gneiss and as lenses within garnetiferous quartzo-feldspathic gneiss and are composed of clinopyroxene, garnet, calcic amphiboles, wollastonite, plagioclase, K-feldspar, epidote, quartz, calcite, magnetite, and minor sulphides. Calc-silicates within the main orebody of the Geco mine are characterized by clinopyroxene, calcic amphiboles (Cl–K-rich hastingsitic and ferro-edenitic hornblende, ferro-edenite (up to 4.7 wt.% Cl); and ferroactinolite (6.7 wt.% MnO)), garnet, epidote (including an epidote rich in rare-earth elements and Cl), calcite, quartz, and abundant sulphides. Calc-silicates within the basal 4/2 Copper Zone of the Geco mine contain garnet, gahnite, sphalerite, ferroactinolite (8.5 wt.% MnO), epidote, quartz, biotite, plagioclase, chlorite, muscovite, K-feldspar, and pyrosmalite (with Mn/(Mn + Fe) ratio ranging from 0.21 to 0.61, and up to 3.9 wt.% Cl). The calc-silicates probably represent metasomatic remobilization of dispersed Ca (and Cl) from sea-floor hydrothermal alteration of mafic to intermediate volcanic rocks and are only indirectly related to the hypothesized syngenetic ore-forming processes for the associated base metal sulphide deposits. The calc-silicates formed initially at about 600 °C and 3–5 kbar (1 kbar = 100 MPa) in a mildly reducing environment (from 1 log unit above to 1 log unit below the fayalite–magnetite–quartz buffer) during the upper-amphibolite- to granulite-facies regional metamorphism and were altered subsequently at lower temperatures (<500 °C).
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Gericke, Mariekie. "Base Metal Tank Bioleaching: From Laboratory Test Work to Commercialization". Advanced Materials Research 1130 (listopad 2015): 197–200. http://dx.doi.org/10.4028/www.scientific.net/amr.1130.197.
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The tank bioleaching of metal sulphides is an established technology. Commercial success started with the treatment of refractory gold concentrates using mesophilic micro-organisms, followed by the development of tank bioleaching processes for the treatment of base metal concentrates. This was initially a mesophilic process treating secondary copper sulphides, pentlandite and cobaltiferous pyrite. There was though limited potential for recovery of copper from chalcopyrite concentrates due to low copper extractions. Over the past decades the optimization of bioleaching processes for the treatment of chalcopyrite ores and concentrates has been the subject of numerous research programmes. The use of bioleaching for the treatment of pure chalcopyrite concentrates has, however, not found commercial application mainly due to competitive smelter prices. With this in mind, Mintek’s base metal bioleaching development over the past few years focused on the treatment of complex polymetallic concentrates containing contaminants such as As, Bi, Pb and Sb as a niche application for tank bioleaching processes. These contaminants pose problems when processed via the smelting route. This paper reviews Mintek’s involvement in the development of base metal tank bioleaching processes for the treatment of chalcopyrite and polymetallic concentrates. Examples of laboratory-scale test work as well as larger scale demonstration and commercialization of the technology are highlighted.
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Genge, M. J., i M. M. Grady. "Unequilibrated assemblages of sulphide, metal and oxide in the fusion crusts of the enstatite chondrite meteorites". Mineralogical Magazine 63, nr 4 (sierpień 1999): 473–88. http://dx.doi.org/10.1180/002646199548655.
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AbstractThe fusion crusts of meteorites form due to heating during atmospheric entry and have mineralogies which are strongly influenced by changes in oxidation state. We have studied the fusion crusts of the most reduced primitive meteorite group, the enstatite chondrites, since they should demonstrate pronounced changes on oxidation. The fusion crusts are dominated by highly unequilibrated assemblages of sulphide, metal and oxide with compositions indicative of progressive oxidation by the reaction with atmospheric oxygen. Troilite becomes depleted in Ti, Cr and Mn, and enriched in Ni with increasing oxidation. Enrichments in the Ni-contents of kamacite and depletions in Si-content also occur with oxidation, although contemporaneous enrichments in Si within metal droplets occurs by partial melting. Assemblages dominated by Fe-oxide are found within fusion crusts as reaction rims on metal, as veins and within troilite-metal assemblages as droplets and formed by oxidation of metal during heating. Despite the evidence for large increases in redox state during heating, fusion crusts also contain lithophile sulphides indicating a high degree of disequilibrium during the atmospheric reprocessing of enstatite chondrite materials. Based on comparisons with experimental phase relations, ablation rates of 0.08–0.25 cm s−1 are predicted from the thermal gradients recorded in fusion crusts; these rates are broadly similar to those suggested for other meteorite groups.
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Débart, A., L. Dupont, R. Patrice i J. M. Tarascon. "Reactivity of transition metal (Co, Ni, Cu) sulphides versus lithium: The intriguing case of the copper sulphide". Solid State Sciences 8, nr 6 (czerwiec 2006): 640–51. http://dx.doi.org/10.1016/j.solidstatesciences.2006.01.013.
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Friedrich, G., V. Scheps i S. Keyssner. "Preliminary Results of a Drilling Program for Base Metal Sulphides in the Northern Eifel (West Germany)". Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 171, nr 1-3 (26.09.1985): 281–95. http://dx.doi.org/10.1127/njgpa/171/1985/281.
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Dorokhov, Viktor S., Maxim A. Kamorin, Nadezhda N. Rozhdestvenskaya i Victor M. Kogan. "Synthesis and conversion of alcohols over modified transition metal sulphides". Comptes Rendus Chimie 19, nr 10 (październik 2016): 1184–93. http://dx.doi.org/10.1016/j.crci.2015.11.018.
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