Fázové složení artefaktů po Cu-Zn-Pb metalurgické aktivitě ze Smetanovy ulice v Jablonci nad Nisou (Česká republika)

Rapidly transitioning to low‐carbon energy sources is essential not only for reducing the direct emissions of toxic mercury (Hg) from coal combustion but also for fulfilling our commitments under the Minamata Convention. However, this shift could significantly increase the demand for nonferrous metals that are intensive in Hg, potentially negating the benefits of reduced Hg emissions. The effect of these nonferrous metal inputs on the overall effectiveness of Hg reduction efforts within the power sector's transition is an area that requires further investigation. Here, we evaluate the impact of China's low‐carbon power transition on Hg emissions from coal combustion and nonferrous metal (mainly copper, zinc, and lead) smelting. We find that the low‐carbon power transition will lead to a significant reduction (101.81 tons) of over 90% in annual Hg emissions originating from coal combustion during the period from 2021 to 2060. Unexpectedly, the pursuit of renewable energy, particularly in photovoltaic and wind power, is likely to result in a twofold increase in annual mercury (Hg) emissions from nonferrous metal smelting, totaling 5.07 tons, under current industry practices. The cumulative emissions from nonferrous metal smelting is estimated to be 370.44 tons during 2021–2060, including 65.80% power transmission equipment related and 34.30 % power generation equipment related emissions. Overall reduction through the adoption of coordinated measures in the power and nonferrous metals sectors could cut cumulative Hg emissions from nonferrous metal smelting by 57% (211.37 tons) during 2021–2060. The study emphasizes the critical need to manage emissions from metal production for a sustainable low‐carbon energy transition.

The most common machinability parameters used for non-ferrous metals – tool life, surface finish, and swarf size and shape – are reviewed. The microstructure of ‘free-machining’ non-ferrous alloys is controlled primarily by manufacturing procedures, e.g. casting technique, extrusion conditions, heat treatment, and aging, and by alloy composition. Variations in machinability so produced, particularly in relation to copper-base alloys, are discussed. Recent BNF work showed conclusively that the size and distribution of the lead-rich phase in leaded brass and the CU2S phase in sulphur-copper alloys controlled the tool wear rate in single-point turning operations. However, in drilling, composition alone was the controlling factor. The presence of hard particles (precipitates) and inclusions in either type of alloy was detrimental to tool life, as illustrated by iron in brass and oxygen and phosphorus in dilute copper alloys. The effects of variations in production methods for aluminium alloys are disc...

Metalworking at Megiddo during the Late Bronze and Iron Ages

Ferromanganese formations are among the major solid mineral resources in the World Ocean. They are characterized by high contents of Fe, Mn, and often nonferrous and noble metals. The issue of the mode of occurrence and genesis of noble and nonferrous metals in the FMS long ago attracted the attention of researchers. However, this issue remains debatable. According to some researchers, the metals mentioned above are extracted from seawater by manganese and iron hydroxides. Other researchers believe that the metals are derived from postmagmatic and hydrothermal solutions. Proponents of the extraterrestrial origin have suggested that platinum group elements (PGE) and some other heavy metals could be incorporated as cosmogenic spherules during the growth of ferromanganese formations. However, all these hypotheses remain controversial. We investigated ferromanganese crusts from the Kashevarov Bank, Deryugin Basin, and Akademiya Nauk Rise in the central part of the Sea of Okhotsk (Fig. 1). Ore crusts from this region are thin (up to 2 cm), usually homogeneous, and vaguely layered (Fig. 2a). The slope of the Kashevarov Bank also contains oolitic crusts related to the cementation of sandy sediment by ferromanganese hydroxides. However, the predominant crust type is characterized by a monolithic upper layer (3 to 4 mm thick) and an oolitic lower layer (Fig. 2b). Data on the chemical composition showed that the crusts contain almost equal contents of Mn and Fe. The total content of ore elements in them is as much as 30 wt %. The Mn content varies from 5.6 to 16.0%; the Fe content, from 3.9 to 17.7%; and the Mn/Fe ratio, from 0.18 to 1.42. Contents of nonferrous metals are very low (0. n ‐0.0 n %) relative to the oceanic ore crust. The total content of Ni, Co, Cu, Pb, and Zn varies from 0.03 to 0.46%. The content of Au and Ag is 0.01 and 0.24 g/t, respectively. In order to elucidate the mode of occurrence of noble and nonferrous metals, we prepared eight polished samples and examined them with an electron microscope and microprobe analyzer (JXA8100, Jeol, Japan). The results show that all samples contain inclusions of noble and nonferrous metals of different compositions. Native silver is the major constituent. Small grains of gold, iron, copper, tungsten, Fe‐Sb oxides, Zn‐Ag‐Cu sulfides, phosphates of rare earth elements, and intermetallic (Cu‐Zn, Cu‐Ni, Sn‐Pb‐Cu‐Ni, Ni‐ Cr‐Mo, Fe‐Cr‐Ni, and Au‐Cu‐Ag) compounds are the subordinate components (Tables 1, 2; Fig. 3).

Immiscible silicate liquids and phosphoran olivine in Netschaëvo IIE silicate: Analogue for planetesimal core–mantle boundaries

A plagioclase–olivine–spinel–magnetite inclusion from Maralinga (CK): evidence for sequential condensation and solid–gas exchange

Experimental silicate glasses are often used as analog and calibration material for terrestrial and planetary materials. Measurements of Fe oxidation state using electron energy loss spectroscopy (EELS) in an aberration-corrected scanning transmission electron microscope (ac-STEM) show that a suite of experimental silicate (e.g., basaltic, andesitic, rhyolitic) glasses have spatially heterogeneous oxidation states at scales of tens of nanometers. Nano-crystals are observed in several of the glasses, indicating nucleation and incipient crystallization not seen at the scale of electron microprobe analysis (EMPA). Glasses prepared in air are uniformly oxidized while glasses prepared at the iron-wustite (IW) or quartz-fayalite-magnetite (QFM) buffers range from reduced to highly oxidized. EELS spectral shapes indicate that oxidized glasses have tetrahedral Fe3+. The nanoscale compositional and structural heterogeneities present in the experimental glasses mean that the suitability of such glasses as analogs for natural materials and calibration standards depends strongly on the scale of the measurements being done. The electron beam quickly damages silicate glass, but data showing changes in oxidation state among and within samples can be obtained with careful control of the beam current and dwell time. Determination of oxidation state in silicate glasses via STEM-EELS is very challenging, and accurate and reliable measurements of Fe3+/ΣFe require careful sample preparation and control of microscope conditions and benefit from comparison to complementary techniques.

We have developed multiple-year inventories of anthropogenic mercury emissions in China for 1995 through 2003. We estimate that total Hg emissions from all anthropogenic sources increased at an average annual rate of 2.9% during the period 1995-2003, reaching 696 (+/- 307) t in 2003, with a speciation split of 395 t of Hg0, 230 t of Hg2+, and 70 t of Hg(p). Nonferrous metals smelting and coal combustion continue to be the two leading mercury sources in China, as nonferrous metals production and coal consumption keep increasing. Nonferrous metals smelting and coal combustion together contributed approximately 80% of total Hg emissions during the past decade. Hg emissions from coal combustion increased from 202 t in 1995 to 257 t in 2003 at an average annual rate of 3.0%. Among all of the coal consumption sectors, the power sector is the leading one in Hg emissions growth, up by 5.9% annually. Hg emissions from nonferrous metals smelting increased from 230 t in 1995 to 321 t in 2003 at an average annual rate of 4.2%. Although Hg emissions related to gold smelting decreased since 1996, other nonferrous metals such as zinc, lead, and copper contributed significant Hg growth at annual rates of 8.5%, 13.0%, and 6.9%, respectively. At provincial level, the trends of Hg emissions show significant variation. The uncertainty level decreased from +/- 78% (95% confidence interval) in the estimate of total emissions in 1995, to +/- 44% in 2003. This is primarily attributed to the decreased emissions from those Hg sources with the largest uncertainty in both activity levels and emission factors, such as artisanal gold smelting, mercury mining, and battery/fluorescent lamp production.

Using advanced magnetic resonance spectroscopies and small-cluster modeling, atomic structure of radiation-induced point defects in alkali borate, silicate, and borosilicate glasses is fully characterized. It is shown that in boron-containing glasses, most of these point defects are electrons/holes trapped by cation/anion vacancies, such as O1 - - O3 + valence-alternation pairs. In microscopically phase-separated borosilicate glasses, radiation-induced defects are found to cluster at the interface between the borate and silicate phases. Reaction and diffusion dynamics of defect-annealing interstitial hydrogen atoms in boron and silica oxide glasses are studied. The yield of radiolytic O2 is estimated. This oxygen is shown to be the final product of triplet exciton decay. Plausible mechanisms for the oxygen bubble formation are put forward. Two practical conclusions relevant for the EMSP mission are made: First, the yield of radiolytic oxygen is shown to be too low to interfere with the storage of vitrified radioactive waste in the first 10 Kyr. Second, microscopic phase separation is demonstrated to increase both the chemical and radiation stability of borosilicate glass.

In a cooperative agreement with DOE (Contract No. DE- AC22- 95101), the USGS has participated with Physical Sciences, Inc. (PSI) in a project entitled "Toxic Substances From Coal Combustion -A Comprehensive Assessment". Samples from the Pittsburgh, Elkhorn/ Hazard, Illinois No. 6, and Wyodak program coals were examined to determine the mode of occurrence of selected trace elements (As, Se, Cr, Hg, and Ni) using selective leaching, scanning electron microscopy, electron microprobe analysis, and X- ray diffraction techniques. Among other findings, our results indicate that the bulk of the arsenic in the Pittsburgh and Illinois No. 6 coals is in pyrite. High percentages (60- 80%) of arsenic were leached by nitric acid, and microprobe data confirm the presence of arsenic in pyrite in each of these coals (concentrations ranging from <0.01 to 0.09 wt.% of the pyrite grains). In the Elkhorn/ Hazard coal, arsenic may have several modes of occurrences. About 30 percent of the arsenic in the Elkhorn/ Hazard coal was leached by hydrochloric acid, possibly indicating the presence of arsenates that were formed by the oxidation of pyrite. About 25 percent of the arsenic in the Elkhorn/ Hazard coal was leached by nitric acid, suggesting an association with pyrite. Only sixty percent of the total arsenic in the Elkhorn/ Hazard coal was leached. The low percentage of leachable arsenic may be accounted for by unleached pyrite grains, which were detected in solid residues from the nitric acid leach. In the Wyodak coal, arsenic probably occurs in iron oxides or carbonates (35 % arsenic leached by HCl) and clays (15% arsenic leached by HF). Arsenic in the Wyodak coal may also have an organic association, as indicated by low totals for leaching (50% unleached arsenic). In the four program coals 20 to 45 percent of the chromium was leached by hydrofluoric acid, suggesting an association with silicates (probably illite). Microprobe analysis of the Pittsburgh, Elkhorn/ Hazard, and Illinois No. 6 coals confirmed the presence of chromium in illite and possibly in other clays, at concentrations that are near the detection limits. Results related to the forms of occurrence of the other trace elements (Se, Hg, and Ni) are varied; further work in Phase II is planned to determine their mode of occurrence.

Photochemical machining (PCM) is a precise, non-traditional process used for fabricating intricate features in nonferrous alloys. This study aims to optimize PCM parameters for copper-zinc (Cu-Zn) alloys using ferric chloride (FeCl3) as the etchant. The influence of etchant concentration, temperature, and etching time on surface roughness, material removal rate (MRR), and edge deviation was evaluated using a full factorial design. Surface morphology and alloy composition were analyzed through high-resolution electron imaging and elemental analysis. Results revealed that low-zinc alloys like CuZn10 yielded smoother surfaces and lower MRR due to their reduced chemical reactivity. In contrast, high-zinc alloys like CuZn40 exhibited higher MRR but with increased surface roughness and edge deviation. Statistical validation through ANOVA confirmed the significance of all three process parameters. To address conflicting machining objectives, multi-response optimization was carried out using the overall evaluation criterion (OEC), enabling a balanced trade-off among key responses. The findings emphasize the pivotal role of zinc content in determining etching behavior and stress the need for alloy-specific parameter tuning. This work offers a structured approach for enhancing precision and efficiency in PCM of Cu-Zn alloys, contributing to better control and predictability in microfabrication processes.

The Styrian Basin, situated in the transition zone between the Pannonian Basin and the Eastern Alps, is believed to have formed above a lithospheric wedge, which have been affected by a subduction. The Late Miocene-Pliocene alkali basalts sampled the subcontinental lithospheric mantle beneath the area, bringing mantle xenoliths to the surface (e.g., [1] [2]). These xenoliths are amphibole-rich, indicating extensive modal metasomatism at mantle depth. Our goal is to better understand the possible fluid and melt-related processes in these xenoliths by studying fluid and melt inclusions in them. In the studied samples, one category of xenoliths contains both fluid and melt inclusions (co-entrapped), while the other contains only fluid inclusions. We carried out 3D confocal Raman mapping, Focused Ion Beam-Scanning Electron Microscopy (FIB-SEM), Electron Microprobe Analysis (EMPA), and Scanning Electron Microscope with Energy Dispersive Spectroscopy (SEM-EDS). Our primary objectives are to 1) gain insights into the nature of metasomatic agents based on fluid and melt inclusions and 2) test the applicability of 3D Raman mapping on inclusions. The studied inclusions are primary (fluid inclusions) and pseudosecondary (fluid and melt inclusions), occurring in orthopyroxene, clinopyroxene, and amphibole. The fluid inclusions are irregular to negative crystal-shaped (3-100 &amp;#956;m), whereas melt inclusions are glass-rich with rounded to negative crystal shapes (4-15 &amp;#956;m). A series of 3D Raman mapping on these fluid inclusions has revealed complex phase assemblages comprising fluid and solid phases (magnesite, silicate glass, pyrite, talc, anhydrite, and nahcolite). The fluid is dominated by CO2 (up to 99.3 mol%) and H2O (up to 8.7 mol%). EMPA indicates that the trapped silicate glass in the melt inclusions is H2O-bearing (up to 3.3 wt%) and exhibits an evolved composition (i.e., trachyandesitic composition with SiO2 between 54.31-60.65 wt%) relative to the host basalt of the studied xenoliths. We discovered pargasitic amphiboles within SiO2-rich glass in the melt inclusion that co-entrapped with the CO2-H2O-rich fluid phase (where H2O content is likely high relative to mantle fluids). This strongly suggests that amphiboles were likely crystallized from an immiscible SiO2-rich melt and CO2-H2O-rich fluid that could have been circulating in the mantle wedge above a subducted slab. This immiscible component is suggested to be a metasomatic agent that modified this mantle portion beneath the Styrian Basin. &amp;#160;Furthermore, this study revealed that the laser-induced heating effect could overestimate sulfides in the 3D Raman models, while silicate glass could be underrepresented due to its low Raman scattering properties. However, complementary FIB-SEM serial slicing provides a clear outline of silicate glass in fluid inclusions. Despite these limitations, 3D Raman mapping has proven to be a powerful tool for unravelling complex phase assemblages in inclusions. This research was supported by the NKFIH_FK research fund nr. 132418 to M. Berkesi. Part of this research was funded by the Doctoral School of Earth Sciences of the University of P&amp;#233;cs. &amp;#160;

Results of assessment of the stability and homogeneity of the Be−Mg−Al−silicate glass synthesized by the authors and possibilities of its use as a quality control material (QCM) in the X-ray electron probe microanalysis (EPMA) of Be-bearing silicate materials, i.e., crystals and quenched melts (glasses), and also silicates and oxides are presented. The homogeneity of the samples was studied at the macro- (10–100 μm) and microlevels (1–10 μm) and assessed according to the scheme of dispersion analysis. A possibility of using the Be–silicate glass as a certified reference material for the determination of the concentrations of Mg, Al, Si was estimated using international reference materials of glasses and QCM of minerals of the known composition. The metrological performance of the experimental data obtained suggest that the studied glass can be used as a QCM in the EPMA of Be-bearing silicate materials, silicates, and oxides. The use of the Be-silicate glass as a certified reference material of composition in EPMA ensures acquisition of satisfactory data on the composition of minerals including cordierite and beryllium cordierite, beryllium indialite, beryl and also of metastable phases of chrysoberyl and compounds with the structure of β-quartz and petalite.

Anthropogenic atmospheric emissions of cadmium in China

The effect of aluminium on the equilibrium phases of the Cu-Zn alloys has been studied within the range of chemical compositions of interest to brass producers. Ternary alloys were cast by melting two Cu-Zn base alloys (with ∼59.5% and ∼61.2 wt.% Cu) followed by the addition of aluminium up to 3.68 wt.%. Isothermal homogenization, followed by rapid cooling, has been used to determine the equilibrium phases at different temperatures. The alloys have been observed by scanning electron microscopy (SEM) and the respective chemical analysis determined by electron probe microanalysis (EPMA). Statistical analysis of the results enables a correlation of the chemical compositions of the equilibrium phases with temperature within composition range of the study.