Hasil untuk "Mineral industries. Metal trade"

Đukić Miloš, Vasiljević Sanela, Adamović Dragana et al.

The validity of test results represents one of the most important aspects in the implementation of the SRPS ISO/IEC 17025 standard and is a key factor in the operation of accredited laboratories. Ensuring reliable results is achieved through continuous monitoring and analysis of the obtained data, using appropriate statistical methods. One of the most effective methods for this purpose is the use of control charts, which provide a visual representation of the analytical system's stability and quickly indicate deviations or the occurrence of significant changes in the process. The aim of this paper is to present the theoretical basis and application of various types of control charts (X, X-blank, R, r and D) in chemical analysis, with a special focus on their use in accredited laboratories.

Tasić Viša, Topalović Dušan, Radović Bojan et al.

This paper presents the results of testing the characteristics of portable PM monitors in laboratory conditions. The test was conducted in the Laboratory for Applied Informatics and Computer Engineering of the Mining and Metallurgy Institute Bor during February 2025. The results of measuring the concentrations of suspended particles PM10 and PM2.5 obtained using the reference gravimetric measurement method were compared with the results of PM monitors, which use low-cost sensors based on the principle of light scattering to determine the concentrations of suspended particles. The results of measuring PM concentrations using portable monitors are lower than the results obtained using the gravimetric method by 20-30%, for both observed PM fractions. The correlation coefficients (Pearson's) between the PM monitor results are higher than 0.98, which indicates an exceptional agreement between the PM monitor measurement results. Also, comparisons were made between the results of measuring the temperature and relative humidity of the reference instrument and the results of the temperature and relative humidity sensors installed in the PM monitors. Deviations of temperature measurement results compared with the reference instrument are within the limits of ± 1°C, and in the case of relative air humidity, the deviations are within the boundaries of ± 5% RH compared with the reference instrument (average hourly values).

Milivojević Katarina, Supić Mlađen, Ignjatović Dragan et al.

The southern slope of the Gacko open-pit mine shows pronounced instability after an earthquake and a large water intrusion during 2022, which led to terrain deformations and interruption of exploitation. The aim of the work is to, based on engineering geological, geophysical, hydrogeological and laboratory research, examine the structure and behavior of the slope, identify key instability mechanisms and define basic remediation measures. Eleven engineering geological units of different properties were identified, including particularly unfavorable zones with plastic clays and degraded marls, as well as a predisposed slip plane at the contact of unit 1N and limestone 2K. Geodetic measurements confirm continuous movements. The results allow for a reliable understanding of the instability process and the definition of remediation solutions necessary for safe exploitation.

Peter Klimek, Sophia Baum, Markus Gerschberger et al.

Rare earth elements (REEs) are critical to a wide range of clean and high-tech applications, yet global trade dependencies expose countries to vulnerabilities across production networks. Here, we construct a multi-tiered input-output trade network spanning 168 REE-related product codes from 2007-2023 using a novel AI-augmented statistical framework. We identify significant differences between dependencies in upstream and intermediate (input) products, revealing that exposure and supplier concentration are systematically higher in input products, while systemic trade risk is lower, suggesting localized vulnerabilities. By computing network-based dependency indicators across countries and over time, we classify economies into five distinct clusters that capture structural differences in rare-earth reliance. China dominates the low-risk, high-influence cluster, while the EU and US remain vulnerable at intermediate tiers. Regression analyses show that high exposure across all products predicts future export strength, consistent with import substitution. However, high systemic trade risk in input products like magnets, advanced ceramics or phosphors, significantly impedes the development of comparative advantage. These results demonstrate that the structure of strategic dependencies is tier-specific, with critical implications for industrial resilience and policy design. Effective mitigation strategies must move beyond raw material access and directly address country-specific chokepoints in midstream processing and critical input production.

Sujay Nair, Evan Coleman, Sherrie Wang et al.

Minerals play a critical role in the advanced energy technologies necessary for decarbonization, but characterizing mineral deposits hidden underground remains costly and challenging. Inspired by recent progress in generative modeling, we develop a learning method which infers the locations of minerals by masking and infilling geospatial maps of resource availability. We demonstrate this technique using mineral data for the conterminous United States, and train performant models, with the best achieving Dice coefficients of $0.31 \pm 0.01$ and recalls of $0.22 \pm 0.02$ on test data at 1$\times$1 mi$^2$ spatial resolution. One major advantage of our approach is that it can easily incorporate auxiliary data sources for prediction which may be more abundant than mineral data. We highlight the capabilities of our model by adding input layers derived from geophysical sources, along with a nation-wide ground survey of soils originally intended for agronomic purposes. We find that employing such auxiliary features can improve inference performance, while also enabling model evaluation in regions with no recorded minerals.

Jie Chen, Sanmang Wu, Qiuping Li

This study systematically examines the evolution and driving factors of embodied CO 2 emission transfers in trade between Chinese provinces and ASEAN countries from 2002 to 2017. Employing a global multi-regional input–output (MRIO) model embedded with Chinese provincial data and structural decomposition analysis (SDA), we quantify the CO 2 emissions embodied in exports (EEE) from 30 Chinese provinces to 10 ASEAN member countries. The analysis explores temporal trends, provincial and sectoral distribution, export routes, and driving forces. The key findings are as follows: (1) As China-ASEAN economic ties have strengthened, China’s EEE to ASEAN have shown a sustained upward trend, with Indonesia, Malaysia, Thailand, and Vietnam being the primary recipients. Heavy industries such as electricity, metal smelting, non-metallic mineral products, and chemicals are the dominant sources of these embodied emissions. (2) Coastal provinces such as Guangdong, Jiangsu, and Zhejiang have consistently served as major contributors to EEE. However, the contribution from several inland provinces has increased in later periods, revealing a spatial pattern of “coastal dominance and inland indirect participation” in interprovincial carbon transfer. (3) The export routes have shifted from predominantly international circulation toward a coexistence of domestic and international dual circulation, indicating the growing resilience of China’s domestic market and supply chains under the “dual circulation” strategy. (4) The expansion of final demand in ASEAN countries is identified as the primary driver behind China’s increasing EEE, whereas reductions in carbon intensity and structural upgrading of exports have partially offset the growth in emissions. This study highlights the importance of holistically considering inter-provincial disparities in emission transfers and advocates for improving regional and sectoral coordination in carbon mitigation policies, aiming to facilitate a green transition in China–ASEAN trade relations.

Guangyao Deng, Siqian Hou, Yuting Liu

Accelerating the construction and optimization of national value chains is of great significance to reducing both pollution and carbon emissions and promoting green economic growth. In accordance with the input–output table and carbon emission statistics of China in 2012, 2015, and 2017, in this paper, we use the total trade decomposition method and the value chain decomposition method to decompose the embodied carbon emissions and the embeddedness of national value chains. Subsequently, we empirically study, for the first time, the impact of the degree of domestic value chain embedding on implicit carbon emissions using the calculated results. The results show the following: (1) The top three provinces with embodied carbon emissions are Shandong, Hebei, and Jiangsu, while the top four industries are the production and supply of electricity and heat; metal smelting and rolling processing; non-metallic mineral products; and transportation, warehousing, and postal services. (2) The degree of forward and backward national value chain embeddedness in Chinese provinces has increased, and the degree of forward embeddedness in most provinces and industries is lower than that of backward embeddedness. (3) The embeddedness of domestic value chains and embodied carbon emissions is always negatively correlated, and this conclusion is still valid after robustness and endogeneity tests. (4) There is industrial heterogeneity in the impact of the degree of embeddedness of domestic value chains on embodied carbon emissions.

Hao Zhan, Chengzhi Li, Yi Kang et al.

Mineral elements typically act as transported substrates for metal tolerance proteins (MTPs). The chelation of MTPs with heavy metal ions is a suggestive detoxification pathway in plants; therefore, the trade-off between transporting mineral elements and chelating excess toxic metal ions is inevitable. Gallium (Ga) is an emerging pollutant associated with high-tech industries. This study investigated the impact of Ga stress on MTPs, subsequently altering the transport and distribution of mineral elements. Gallium exposure reduced rice seedling biomass, with roots accumulating more Ga than shoots. Ga stress also changed the rice plants’ subcellular mineral element distribution. PCR assays showed that Ga stress negatively affected all genes belonging to the Mn group, except OsMTP9. While Mn accumulation in the rice cellular compartments did not respond positively to Ga stress, OsMTP8, OsMTP8.1, OsMTP11, and OsMTP11.1 were found to be intimately connected to Mn transport and repressed by increased Ga accumulation in roots. Mg and Cu accumulated in the cytosol and organelles of Ga-treated rice plants, while OsMTP9 expression increased, demonstrating its importance in transporting Mg and Cu. A positive link between Ga stress and Zn accumulation in the cytosol and organelles was found, and OsMTP7 and OsMTP12 expression was positive, suggesting that Ga stress did not impair their Zn transport. Notably, Ga exposure down-regulated Fe-transporting OsMTP1 and OsMTP6, wherein the subcellular concentrations of Fe showed negative responses to Ga accumulation. These findings provide valuable insights into elucidating the roles of OsMTPs in Ga tolerance and the transport of these mineral elements.

Zheng Jin

With the increasing emphasis on global environmental issues and the deepening of the concept of sustainable development, the application and impact of environmental regulation are becoming increasingly prominent. Especially for pollution-intensive products, the impact of environmental regulation on the import and export trade of different pollution-intensive products is subject to various factors. The impact of environmental regulation on different resource-based industries still needs a lot of research. Through the method of literature analysis, this paper integrates the literature on the impact of environmental regulation on resource-based industries and concludes that the overall impact of environmental regulation on resource-based industries is positive and significant. For the paper and pulp industry, both exogenous and endogenous environmental regulations have enhanced its comparative advantage. For the non-ferrous metal and non-metallic mineral industry, environmental regulation can promote its technological progress and gain comparative advantage.

Kržanović Daniel, Gomilanović Miljan, Jovanović Milenko et al.

The disposal of mining waste is an indispensable technological operation during the exploitation of mineral raw materials and mining activity. A new technological approach to the disposal of mining waste, which is presented in this paper, predicts that all mining waste generated during the excavation and processing of ore in open pit mines and in flotation is disposed of in integrated tailings dumps. In this way, the construction of a flotation tailings pond is eliminated, i.e., the permanent risk that may arise due to an accident situation for the environment, facilities and population located downstream of the originally planned location of the flotation tailings pond is eliminated

Célestin Coquidé, José Lages, Dima L. Shepelyansky

We extend the opinion formation approach to probe the world influence of economical organizations. Our opinion formation model mimics a battle between currencies within the international trade network. Based on the United Nations Comtrade database, we construct the world trade network for the years of the last decade from 2010 to 2020. We consider different core groups constituted by countries preferring to trade in a specific currency. We will consider principally two core groups, namely, 5 Anglo-Saxon countries which prefer to trade in US dollar and the 11 BRICS+ which prefer to trade in a hypothetical currency, hereafter called BRI, pegged to their economies. We determine the trade currency preference of the other countries via a Monte Carlo process depending on the direct transactions between the countries. The results obtained in the frame of this mathematical model show that starting from year 2014 the majority of the world countries would have preferred to trade in BRI than USD. The Monte Carlo process reaches a steady state with 3 distinct groups: two groups of countries preferring, whatever is the initial distribution of the trade currency preferences, to trade, one in BRI and the other in USD, and a third group of countries swinging as a whole between USD and BRI depending on the initial distribution of the trade currency preferences. We also analyze the battle between USD, EUR and BRI, and present the reduced Google matrix description of the trade relations between the Anglo-Saxon countries and the BRICS+.

Petrović Ana, Marković Radmila, Božić Dragana

Metal foam is a cellular structure composed of solid metal with a high proportion of gas-filled pores. The main division of metal foams is into foams with the open and closed cells, on which the area of their application mostly depends. The open-cell foams are suitable for the wastewater treatment process, as they allow the water flow through the pores trapping the toxic substances in the pores. This study provides a summary of literature data on morphology and application the copper metal foams in the wastewater treatment.

Célestin Coquidé, José Lages, Dima L. Shepelyansky

During his state visit to China in April 2023, Brazilian President Lula proposed the creation of a trade currency supported by the BRICS countries. Using the United Nations Comtrade database, providing the frame of the world trade network associated to 194 UN countries during the decade 2010 - 2020, we study a mathematical model of influence battle of three currencies, namely, the US dollar, the euro, and such a hypothetical BRICS currency. In this model, a country trade preference for one of the three currencies is determined by a multiplicative factor based on trade flows between countries and their relative weights in the global international trade. The three currency seed groups are formed by 9 eurozone countries for the euro, 5 Anglo-Saxon countries for the US dollar and the 5 BRICS countries for the new proposed currency. The countries belonging to these 3 currency seed groups trade only with their own associated currency whereas the other countries choose their preferred trade currency as a function of the trade relations with their commercial partners. The trade currency preferences of countries are determined on the basis of a Monte Carlo modeling of Ising type interactions in magnetic spin systems commonly used to model opinion formation in social networks. We adapt here these models to the world trade network analysis. The results obtained from our mathematical modeling of the structure of the global trade network show that as early as 2012 about 58 percent of countries would have preferred to trade with the BRICS currency, 23 percent with the euro and 19 percent with the US dollar. Our results announce favorable prospects for a dominance of the BRICS currency in international trade, if only trade relations are taken into account, whereas political and other aspects are neglected.

Sourish Dutta

Studying intra-industry trade involves theoretical explanations and empirical methods to measure the phenomenon. Indicators have been developed to measure the intensity of intra-industry trade, leading to theoretical models explaining its determinants. It is essential to distinguish between horizontal and vertical differentiation in empirical analyses. The determinants and consequences of intra-industry trade depend on whether the traded products differ in quality. A method for distinguishing between vertical and horizontal differentiation involves comparing exports' unit value to imports for each industry's intra-industry trade. This approach has limitations, leading to the need for an alternative method.

A.V. Nogovitsyn, V.L. Lakhnenko, I.R. Baranov

Today, in the world, it is widely used in the production of aerospace equipment, sea vessels, railway transport and cars have high-strength aluminum alloys Al-Zn-Mg-Cu (for example, B95) and alloys of medium Al-Mg (AMg5), Al-Si-Mg ( AD35) and increased strength Al-Cu-Mg (D16). An in-depth study of individual factors that directly affect the structure of the work piece can be crucial for improving product quality during further thermomechanical processing. The article defines data on the grain size of the primary phase of aluminum alloys depending on the cooling rate of castings of various aluminum alloys (AD35, B95, D16, AMg5). It is shown that an increase in the cooling rate from 2-8 ° C / s to almost 1000 ° C / s leads to a decrease in the grain size of the фазы-phase from 200 μm to 10-40 μm. As a result of the experiments carried out in the work, the intervals of hardening of the investigated aluminum alloys were determined. It is shown that aluminum alloys containing copper in the chemical composition (≥1%) have a significantly wider crystallization range, in particular, B95 (1600C) and D16 ( 1320C). The samples of strip used in this work from high-strength aluminum alloys obtained by roll casting, to expand the range of investigated cooling rates, have a homogeneous structure with a uniform distribution of phase components, which ensures high functional properties of rolled products from high-strength, heat-strengthened alloys of the Al-Cu and AL-Zn systems. The obtained data of the research results can be recommended for use in the development of the domestic technology of roll casting of high-strength aluminum alloys.

Matthew G. Shaw, Matthew S. Humbert, Geoffrey A. Brooks et al.

The lunar surface is extremely harsh and current mineral processing and metal extraction technologies are not adequately equipped to address this environment. In this paper we review the metals available for extraction and conditions at the lunar surface, and analyse the challenges associated with comminution, beneficiation, and metal extraction operations. The potential beneficial effects of the natural lunar conditions are also evaluated. This investigation concludes that process plant design on the lunar surface will favour lightweight, schematically simple flow sheets that enable automation, and that utilise the local environment wherever possible. The elimination of traditional comminution and beneficiation stages and their replacement with basic classification could be economically favourable. The most promising metal reduction pathways are identified as molten regolith electrolysis, and vacuum thermal dissociation, other processes with merit are hydrogen reduction, carbothermal reduction, and solid electrolysis. Finally, it is identified that a significant research effort in all areas of astrometallurgy will be required before industrial-sized extra-terrestrial mineral processing and metal extraction operations will be viable.

Y. G. Aftandiliants, К.G. Lopatko

The results of the study of the effect of nanoparticles in the shell of iron oxide Fe2O3, which when injected into the melt and heated up to melt temperature is converted into oxide Fe3O4, on the microstructure of hardened and tempered steel 25GSL and its properties. It is shown that in modified steel martensite crystals thickness is reduced compared to the original steel in average 1.9 times after the quenching, tempered martensite crystal length after tempering hardened steel at 200oC - 3 times, the plate cementite length in troostite after tempering hardened steel at 450 оС – 1,4 times, the carbide length of after tempering of steel at 550 оС – 1,6 times. It has been found that modification of iron nanoparticles in a shell of Fe3O4 oxide leads to dispersion of the subgrain structure (regions of coherent scattering) and to the decrease of the crystal lattice parameters of solid solutions. The mechanism of nanoparticle influence on the reduction of the crystal lattice parameters of solid solutions, which is to accelerate the diffusion of interstitial atoms of the elements into the zones of high stress on the nanoparticles surface, is proposed. It is determined that the optimal improvement mode of the modified steel is quenching at 900 °C and tempering at 550 °C. The yield, tensile strengths and toughness of the modified steel are 894 MPa, 993 MPa and 92 J/mm2, respectively, on 62, 41 and 14% higher than the original steel. The injection of iron nanoparticles in a refractory shell into the steel melt before crystallization predetermines the effective modification and enhancement of mechanical properties.

V.I. Shmyrko, A.V. Korobko, A.O. Pysarskiy et al.

The improving reliability of stationary gas turbines depends on the guaranteed efficiency of turbine blades tested by the complex effects of high temperatures, mechanical loads, and aggressive medium. Turbine blades are critical parts with complex geometric forms made of nickel-base superalloys. The complexity of forecasting of their lifetime is explained by the data missing on the strength and corrosion resistance during their lifetime. The investigation of their characteristics takes much time and is expensive. Nowadays, the long-term strength calculations are carried out using various methods of extrapolation of the results of short-term tests. In order to forecast the high-temperature characteristics of alloys operating in an oxidizing medium, the time-temperature equations of the long-term strength by Miller-Larson, Cherby-Dorn, Manson-Haferd are most widely used. The studies of the possibility to use parametric time-temperature equations to forecasting the heat resistance of parts tested high-temperature sulfide-oxiding impact are presented. The most reliable parametric method of forecasting the trouble-free operation of the turbine blades has been determined. The analysis of the experimental and calculated values of the long-term strength was showed that under aggressive conditions, the calculation of the time to rupture is possible only for the corrosion-resistant alloys IN-738, ЗМИ-3У. A significant increase in the scattering of experimental and extrapolated features is characteristic, regardless of the method was considered. It was established to make a forecast for ВЖЛ 12У alloy with an increase in extrapolation time to 5,000 hours at 850 °C and above, it is impossible. The maximum resource calculation of trouble-free operation of parts allows not only to save expensive heatproof materials, decrease labor efforts for their manufacture and repair process, but also to increase the reliable operation of gas-turbine engines.

Yarovytsyn O.V.

Under conditions of multilayer microplasma powder overlay welding process of nickel-base difficult to weld high temperature strength alloys with a content of the strengthening γ׳- phase more than 50 vol. % the tendency to the reheating cracks formation in the corresponding welded joint "cast-deposited metal" from is largely determined by the structure and properties of the deposited metal. With appropriate research studies of the crack formation tendency, it was proposed not to post factum quantitatively evaluate its manifestations by the number and length of cracks, but to focus on studies of the preliminary resistance stage to their formation in the overlay metal. It is shown that an objective method for the deformation ability studying can be tensile testing at elevated temperatures (1000 ° C) of overlay metal samples. This allows us to move from the two-dimensional system of its assessment “temperature T - critical strain ε” when using a common machine test according to the international standard for hot crack testing resistance ISO 17641: 2005 to the three-dimensional system “temperature T - critical stress σ (Rmcr ) - critical deformation ε (Acr)”. For the overlay metal ZhS32 obtained by the microplasma powder overlay welding process, in the state immediately after deposition, the limited deformation capacity at 1000 °C was established: Rmcr ~ 345 МРа (tensile strength); Acr ~ 0,1 % (percentage elongation). Based on the previously established limited deformation ability of the ZhS6K overlay metal in the after deposition state, it is proposed to use the quantitative criterion ε 1000°C (А1000°C) for predictive assessments of the possibility of ensuring the technological strength of the overlay metal of nickel-base difficult to weld high temperature strength alloys. The reduced level of mechanical properties of the overlay metal ZhS32 after its crystallization in the welding pool is associated to the some its primary structure features. Using scanning electron microscopy, the following differences were established in comparison with a similar cast metal of the ZhS32 alloy: dendritic cell cross section; dispersion and uniform distribution of the carbide phase particles; the visual signs absence of the release of strengthening γ׳-phase particles on the dendrite axes. It is shown that the presence of dispersed hardening in the structure of nickel-base high temperature strength alloys of the ZhS32 and ZhS6 types depends on the cooling rate of the molten metal during crystallization, and in the case of the overlay metal it is finally formed only during subsequent heat treatments in the range of aging-homogenization modes.

S.G. Kondrashova, Ye.V. Saprikin, V.V. Naumyk

The article presents the results of research on the selection of the saturating mixture optimal composition during chromium plating of gray cast iron. It’s carried out the microstructural studies of the surface layer of gray cast iron SCh 12, obtained using saturating mixtures with different activators and their different percentages. Phase X-ray analysis showed that the obtained coatings on cast iron consist of chromium carbides Cr23C6 and Cr7C3. The carbide zone under the same conditions of diffusion saturation is formed at the amounts of activators exceeding 7%. It is shown that the coefficient of relative wear resistance of gray cast iron after diffusion chromium plating is directly dependent on the depth of the diffusion layer. The corrosion resistance of the coating with increasing thickness of the carbide zone also increases. At the same time, heat resistance decreases sharply with increasing percentage of activator. That is, the phase composition and morphology of the layer structure have a significant influence on the oxidation processes According to the method of experiment simplex-lattice planning, mathematical models of the dependences of the depth of the diffusion layer, corrosion resistance, oxidation, and the coefficient of relative wear resistance on the saturating mixture composition were obtained. Based on the obtained dependences, triple "property-composition" diagrams are constructed. The diagrams analysis confirmed the important role of activators in the process of diffusion chromium plating. It is shown that they promote the formation of active chromium atoms, which provides the formation of a continuous carbide coating. It has been established that during diffusion chromium plating of gray cast iron SCh 12 in order to increase the corrosion resistance of the diffusion layer in the saturating mixture, it is necessary to introduce NH4Cl and NH4F activators in an amount of 10…13%. It also provides with an increase in the coefficient of relative wear resistance of gray cast iron. The introduction into the saturating mixture of NH4Cl and NH4F activators, within 4…6% provides an increase in the scale resistance of the diffusion chromium layer by 10…15 times. The use of NaCl and NaF activators during diffusion chromium plating is impractical because when introduced into the mixture it saturates, in an amount of ≤ 13% they do not give a continuous carbide layer, significantly worsens its performance.