Search Results (2,586)

In this work, a series of novel high-entropy alloys CoCrFeNiSiV_x (x = 0.25; 0.5; 0.75; 1.0) with an intermetallic compound structure was proposed. The effect of vanadium addition on the structure, as well as selected mechanical and corrosion properties, was investigated. In the case of the CoCrFeNiSiV_0.25 alloy, the structural analysis revealed the formation of a dual-phase structure consisting of Fe_1.812V_0.907Si_0.906-type and Fe₅Ni₃Si₂-type intermetallic phases. The increase in vanadium concentration results in the crystallization of one Fe_1.812V_0.907Si_0.906 intermetallic phase detected by the X-ray diffraction method. The increase in vanadium content had a beneficial influence on the corrosion resistance of CoCrFeNiSiV_x alloys in 3.5% NaCl. The CoCrFeNiSiV alloy exhibited the lowest corrosion current density of 0.17 μA/cm² and the highest corrosion potential of −0.228 V. The hardness of the alloys investigated increased with vanadium content, reaching 1006 HV for the equimolar alloy. In turn, the lowest friction coefficient of 0.63 ± 0.06 was obtained for the CoCrFeNiSiV_0.75 alloy. The abrasive, fatigue, and oxidative wear were identified as the main wear mechanisms. Full article

Chromium (Cr), a toxic heavy metal, poses significant environmental and health risks when industrial effluents containing Cr are discharged untreated. Addressing this challenge, this study developed a selective chromium removal strategy using IRA-900 resin in a sulfuric acid system with sodium phosphite (NaH₂PO₃) as a complexing agent. In the NaH₂PO₃-H₂SO₄ system, IRA-900 resin exhibited exceptional selectivity for Cr³⁺ with minimal co-adsorption of competing ions. The adsorption process followed the Langmuir isotherm model (R² > 0.99), indicating monolayer chemisorption dominated by homogeneous active sites, and achieved a maximum capacity of 103.56 mg·g⁻¹. Characterization via XPS, FT-IR, and SEM-EDS revealed a two-step mechanism: Cr³⁺ reacts with H₂PO₃⁻ to form an anionic complex, and then the complex undergoes electrostatic interaction and ion exchange with chloride ions (Cl⁻) on the quaternary ammonium groups of the resin. The chromium-loaded resin demonstrated remarkable structural stability, resisting Cr³⁺ desorption under conventional elution conditions. This property provides a novel pathway for chromium solidification in industrial wastewater, effectively minimizing secondary pollution risks. This work advances the design of ligand-assisted ion-exchange systems for targeted heavy metal removal, offering both high selectivity and environmental compatibility in wastewater treatment. Full article

Concentrated Solar Power (CSP) technology is advancing toward higher operating temperatures and lower costs: current systems operate at 565 °C, while next-generation systems are targeted to reach 800 °C to overcome efficiency limitations. In this context, low-cost, adaptable molten chloride salts have emerged as ideal heat transfer and thermal energy storage media. Metallic materials are susceptible to performance degradation under such conditions, which not only shortens equipment service life but also entails potential safety hazards. Thus, the development of alloy protection technologies resistant to molten salt corrosion has become an urgent priority for the deployment of next-generation CSP plants. Research has indicated that high-aluminum stainless steel is a promising candidate due to its unique advantages: it can form a stable Al₂O₃ protective film in oxygen-containing anionic environments, effectively inhibiting the dissolution of Cr, Fe, and other elements, and preventing the penetration of corrosive species. Additionally, the incorporation of magnesium-based corrosion inhibitors into MgCl₂-NaCl-KCl ternary molten salt systems has been proven to be an economically viable and efficient corrosion mitigation strategy. This study focused on high-aluminum 310S heat-resistant steel, with its performance validated through targeted experiments: samples subjected to pre-oxidation at 800 °C for 2 h were immersed in a specific ternary molten salt mixture (20.4 wt.% KCl, 55.1 wt.% MgCl₂, 24.5 wt.% NaCl) containing magnesium corrosion inhibitors, followed by a 600 h static corrosion test at 800 °C. The results revealed that the addition of magnesium significantly enhanced the corrosion resistance of high-aluminum 310S. These findings demonstrate that this material holds application potential in the storage tank and pipeline systems of next-generation CSP plants. Full article

Using the Kaya identity and LMDI method, this study analyzes the influence of population, GDP per capita, energy intensity, and carbon intensity on Xinjiang’s carbon emissions, and compares the effects of industrial structure, energy intensity, and carbon intensity on the industrial sectors during the Eighth to Twelfth Five-Year Plan (FYP) periods. Key findings are as follows: (1) Xinjiang’s carbon emissions center on resource- and energy-intensive sectors, emissions from sectors such as extraction of petroleum and natural gas, fuel processing, chemicals, ceramics and cement, iron and steel, and non-ferrous and power generation accounted for 62% of carbon emissions in 2015; (2) after the Sixth FYP, GDP per capita effect turned into the core driver of carbon emission growth, while the population effect played an auxiliary role. Meanwhile, the energy intensity effect exerted a marked inhibitory impact on the increase in carbon emissions, yet the restraining effect of carbon intensity was comparatively limited; (3) during the Eighth to Twelfth FYPs, carbon emission growth was mainly attributed to industrial structure effects of the mining and washing of coal, extraction of petroleum and natural gas, fuel processing, chemicals, ceramics and cement, iron and steel, non-ferrous and power generation. Energy intensity and carbon intensity effects in various industries inhibited emission growth. Based on new trends in Xinjiang’s socioeconomic development, policy recommendations proposed including promoting the low-carbon transformation of industrial structure, profound restructuring of energy consumption, and improving energy efficiency by advancing energy-saving technology. Full article

One of the cytochrome b₅₆₁ family members in C. elegans, named Cecytb-2, was investigated. Purified recombinant Cecytb-2 showed typical visible absorption spectra, EPR signals, and redox midpoint potentials, very similar to those of human Dcytb, which is responsible for intestinal iron acquisition by its ferric reductase activity. Fast kinetic experiments using pulse radiolysis and stopped-flow techniques showed that Cecytb-2 donates electrons to monodehydroascorbate radicals with a much lower reactivity than other cytochrome b₅₆₁ members, but it can accept electrons from ascorbate (AsA) as rapidly as other members. DEPC treatment of Cecytb-2 caused significant inhibition of electron acceptance from AsA and lowered the midpoint potential of heme b_L. MS/MS MASCOT analyses verified that N-carbethoxylations of conserved Lys98 and heme b_L axial His101 residues on the cytosolic side were major causes of the inhibition. Reconstituted Cecytb-2 in sealed vesicle membranes, in which AsA was entrapped, showed significant transmembrane ferric reductase activity. In situ hybridization analysis revealed that Cecytb-2 mRNA was distributed in intestinal cells. Immunohistochemical analysis indicated that Cecytb-2 resided in intestinal lumens. Knockdown of the Cecytb-2 gene expression in N2 worms indicated a significant suppression of growth under ferrous ion-deficient conditions. Thus, the ferric reductase activity conferred by Cecytb-2 seems to participate in iron acquisition and is very important for normal growth in low-ferrous conditions, confirming that Cecytb-2 is a genuine Dcytb homolog in C. elegans. Full article

The high material cost has restricted the development of concentrated solar power (CSP) systems. In this study, a low-cost alternative material was developed by adding aluminum to 304 stainless steel to form a protective oxide film, thereby enhancing its corrosion resistance to molten salt. Three material variants were tested: untreated hot-rolled plates after solution treatment and cold-rolled high-aluminum 304 stainless steel (High-Al304SS) after solution treatment and annealing treatment. After all samples were immersed in a NaNO₃-KNO₃ mixed salt at 600 °C for 480 h, corrosion products including NaFeO₂, CrO₂, Mn₂O₄, and NiCr₂O₄ were formed. The phase composition was determined by XRD, and the surface and cross-section of the corrosion layer were analyzed by SEM and EDS surface and point analysis. The corrosion rate of the samples was calculated by the weight loss method. Notably, an Al₂O₃-Cr₂O₃ composite oxide film was formed on the sample surface, effectively inhibiting corrosion. The high defect density and grain boundary energy introduced by the cold-rolling process, as well as the precipitation of the second phase during annealing, accelerated the corrosion process of the samples. However, the hot-rolled samples after solution treatment exhibited excellent corrosion resistance (64.43 μm/year) and, through further process optimization, are expected to become an ideal low-cost alternative material for 347H stainless steel (23 μm/year) in CSP systems. Full article

This article focuses on the problem of processing slag waste from non-ferrous metallurgy, in particular, the loss of copper, gold and silver with slag during autogenous smelting in the Vanyukov furnace at the Balkhash Copper Smelter (BMZ). An analysis of factors affecting metal losses, including electrochemical and mechanical components, is presented. This paper offers a comprehensive study of the distribution of Cu, Pb, As, Au and Ag between matte and slag, taking into account the unique characteristics of the raw material and the technological conditions of the copper smelter, which distinguishes it from previous studies. This paper establishes numerical values of dissolved and mechanical losses of valuable metals. It has been established that the most important quantitative result of smelting polymetallic raw materials in a Vanyukov furnace is the proportion of mechanical copper losses in the slag, which is approximately 75–80% of the total copper content in the slag. Mathematical models are proposed to predict the distribution of metals in the process of smelting and loss of copper, gold and silver with slag. It is proposed to integrate model representations into the technology control loop, which will optimize the process of metal recovery. This will lead to an increase in profitability and a reduction in the negative impact on the environment during copper production. Full article

Copper matrix self-lubricating composites are critical for high-temperature industrial applications. In this study, Cu-Ni-Sn-Mo-Gr composites with 3–7 wt.% graphite were fabricated via spark plasma sintering (SPS). The influence of graphite content on microstructure, mechanical properties, and tribological behavior from room temperature (RT) to 500 °C were systematically investigated. The results demonstrate that increasing graphite content progressively reduces density, hardness, and yield strength, whereas it significantly enhances high-temperature tribological performance. The composites with 7 wt.% graphite addition achieve outstanding self-lubricity and wear resistance across the RT-500 °C, achieving an average friction coefficient of 0.09 to 0.21 and a wear rate of 1.32 × 10⁻⁶ to 7.52 × 10⁻⁵ mm³/N·m. Crucially, temperature-dependent lubrication mechanisms govern performance: graphite-dominated films enable friction reduction at RT, while synergistic hybrid films of graphite and in situ-formed metal oxides (Cu₂O, CuO, NiO) sustain effective lubrication at 300–500 °C. Full article

The depletion of high-grade copper ore reserves in Kazakhstan, coupled with the increasing proportion of refractory ores and the high costs of extraction and processing, necessitates the development of efficient and economically viable technological solutions. In this context, biogeotechnology has gained considerable attention. Recently, alternative approaches based on the use of natural organic compounds—so-called bioreagents—have been introduced into the field of bioleaching. The present study aimed to investigate the effect of amino acids, aliphatic alcohols, and alcohol-based industrial by-products, used as bioadditives, on the bioleaching of copper. The results demonstrated that the influence of amino acids on copper bioleaching decreased in the following order: glycine > leucine > cysteine > histidine > asparagine. Furthermore, the addition of fusel oils, a mixture of aliphatic alcohols, to the bioleaching pulp enhanced copper recovery, achieving extraction efficiencies exceeding 90%. Full article

Extremely acidophilic iron- and sulfur-oxidizing bacteria and archaea are used in the processing of different sulfide ores and concentrates (biohydrometallurgical technologies); therefore, studying their metabolic pathways and regulation is an urgent task. Thus, the goal of this work was to compare differential gene expression in the thermoacidophilic archaeal strain, representative of the genus Acidiplasma, a predominant microbial group in bioleach reactors, during growth in the presence of ferrous iron and elemental sulfur as well as pyrite and arsenopyrite, which are the most widespread sulfide minerals, and to obtain novel data on the mechanisms of interaction of microorganisms and sulfide minerals. Transcriptomic analysis revealed metabolic pathways involved in ferrous iron and sulfur oxidation (key processes in sulfide mineral oxidation) and determined their expression dependence on different substrates. It was shown that the blue copper protein sulfocyanin may play an important role in both iron and sulfur oxidation, while sulfur oxidation also involves genes encoding well-known proteins for reduced inorganic sulfur compounds (RISC), sulfur oxygenase reductase (SOR), and thiosulfate quinone oxidoreductase (TQO). The results obtained in the present study may be used in further work to improve biohydrometallurgical technologies. Full article

Organic solvent nanofiltration (OSN) is a promising technology for solute removal from organic media, yet developing membranes with stable separation performance remains challenging. This study presents a solvent-resistant double-crosslinked nanofiltration membrane fabricated via a two-step strategy: preparation of the membrane by the polyion complexion reaction-assisted non-solvent-induced phase inversion (PIC-assisted NIPS) method and then post-crosslinking with hydrothermal treatment followed by quaternization with 1,3,5-tris(bromomethyl)benzene (TBB). To enhance solvent stability, molybdenum sulfide (MoS₂) nanosheets were incorporated into a hydrolyzed polyacrylonitrile (H-PAN) substrate. The H-PAN/MoS₂/PEI base membrane was fabricated by PIC-assisted NIPS with a polyethylenimine (PEI) aqueous solution as the coagulation bath. The membrane subsequently underwent dual crosslinking comprising hydrothermal treatment and 1,3,5-tris(bromomethyl)benzene (TBB)-mediated quaternization crosslinking, ultimately yielding the H-PAN/MoS₂/PEI (Ther.+TBB QCL) composite membrane. These crosslinking procedures reduced the membrane’s separation skin layer thickness from 64 nm (uncrosslinked) to 41 nm. The resultant membrane effectively separated dyes from ethanol, achieving a rejection rate of 97.0 ± 0.9% for anionic dyes (e.g., Congo Red) and a permeance flux of 23.6 ± 0.2 L·m⁻²·h⁻¹·bar⁻¹ at 0.4 MPa. Furthermore, after 30 days of immersion in ethanol at 25 °C, its flux decay rate was markedly lower than that of a non-crosslinked control membrane. The enhanced separation performance and stability are attributed to the thermal crosslinking promoting amide bond formation and the TBB crosslinking introducing quaternary ammonium groups. This double-crosslinking strategy offers a promising approach for preparing high-performance OSN membranes. Full article

The sea cucumber (Apostichopus japonicus) is a commercially important marine species. However, its survival is increasingly threatened by frequent outbreaks of Skin Ulceration Syndrome caused by Vibrio splendidus. This study evaluated the effects of dietary supplementation with ferrous sulfate (FeSO₄) at two concentrations (0.5% and 1%) over short-term (21 days) and long-term (56 days) feeding periods on immune defense, antioxidant capacity, and resistance to V. splendidus infection. Key parameters measured included survival rate, cellular immune activity, antioxidant enzyme levels, and expression of immune-related genes. Long-term (56 days) supplementation with 1% FeSO₄ significantly improved survival after infection (90 ± 4.7%). Phagocytic activity and respiratory burst were enhanced by approximately ~1.9-fold and ~1.8-fold, respectively (p < 0.05). The expression of sod, ferritin, and hsp70 genes was upregulated by ~2.1-fold, ~2.0-fold, and ~1.6-fold, respectively (p < 0.05). These results indicate strengthened cellular immunity and antioxidant capacity. Long-term (56 days) supplementation with 0.5% FeSO₄ increased lysozyme activity (~1.3-fold) and c3 expression (~4-fold) (p < 0.05), thereby enhancing humoral immunity. In contrast, short-term (21 days) supplementation increased ACP and AKP activities by approximately ~2-fold each, and LZM activity by ~1.2-fold (p < 0.05). However, it did not significantly improve survival, indicating limited protective effects. Overall, 56-day dietary supplementation with FeSO₄, particularly at 1%, effectively enhances immune and antioxidant responses in A. japonicus. This supplementation represents a promising strategy for preventing V. splendidus-induced skin ulceration in aquaculture. Full article

Cu–Al–Ni shape memory alloys (SMAs) are attractive for structural and functional applications due to their cost-effectiveness and shape memory behavior. This study systematically investigated the effect of beryllium (Be) addition on the phase stability, microstructure, transformation temperatures, mechanical hardness, corrosion resistance, and wear behavior of Cu–Al–Ni alloys. Alloys with Be contents ranging from 0 to 1.5 wt.% were fabricated via arc melting and subjected to thermal treatment. Characterization techniques included dilatometry, X-ray diffraction (XRD), microhardness testing, potentiodynamic polarization, and pin-on-flat wear testing. The results showed that Be additions ≤ 0.4 wt.% stabilized the martensitic β′ phase, while higher concentrations favored the formation of austenitic β phase with a BCC structure. Hardness increased with Be content, especially in austenitic samples. Corrosion tests revealed that while the 0.2 wt.% Be alloy exhibited the most positive corrosion potential (Ecorr), it also had a higher corrosion rate. Overall, corrosion resistance declined with Be concentrations ≥ 0.6 wt.%. Wear tests demonstrated improved resistance in martensitic alloys, attributed to pseudoplastic deformation. These findings highlight the dual role of Be in modifying phase stability and functional properties, offering useful guidance for designing Cu-based SMAs with tailored performance. Full article

To implement predictive maintenance of units in the practice of metallurgical manufacturers, computer information and diagnostic systems are being developed to assess the current state of individual units throughout their entire life cycle. This publication presents the results of a study on developing an infrared diagnostic system for predictive maintenance of converter units in the non-ferrous metallurgy industry. A 3D mathematical model of the transient heat transfer in the wall of a real operating unit has been developed and numerically implemented to study, analyze, and diagnose surface temperature fields resulting from wear and local damage. To adjust the operation of the mathematical model, the design parameters and the results for operating and technological parameters from an industrial experiment are taken into consideration. Using the model, a full-factor experiment was simulated to study the surface temperature fields resulting from the erosion wear of the wall and the presence of local damage. Based on the simulation results, the optimal time range for thermographic monitoring is determined. A regression dependence was derived to predict the refractory wall wear as a function of the outer surface temperature of the converter unit. The results are part of a comprehensive investigation aimed at developing thermal imaging techniques for converter units in non-ferrous metallurgy. Full article

This study investigated the combined effects of linoleic acid (LA) incorporation and UV irradiation in the presence and absence of ferrous chloride (FeCl₂) on the properties and characteristics of fish skin gelatin films. UV irradiation was implemented at different intensities (10,000–40,000 lux) and with different exposure times (1 and 5 min) by two different methods: irradiating the film-forming solution before casting (S-UV) versus irradiating the pre-cast film (F-UV). The UV treatment significantly increased the elastic modulus (EM) while decreasing the tensile strength (TS), elongation at break (EAB), and water-vapor permeability (WVP) of the films (p < 0.05), irrespective of the irradiation method used. This effect became more pronounced with higher UV intensity and longer exposure times. When both LA and FeCl₂ were present, UV irradiation promoted the formation of non-disulfide covalent bonds, leading to increased cross-linking. This cross-linking improved the film’s strength and decreased its WVP, although it did cause the films to become yellowish. Fourier-transform infrared spectroscopy (FTIR) confirmed interactions between the gelatin and LA, indicated by a decrease in the intensity of Amide-A, Amide-I, and Amide-II bands. A key finding suggested that UV irradiation, combined with LA/FeCl₂ incorporation, could significantly enhance the properties of fish skin gelatin films, especially their water-vapor barrier. The study’s novelty lies in demonstrating that applying the UV treatment to either the film solution or the final film yields similar results, providing flexibility in the manufacturing process. Full article