Recently, due to the depletion of rich copper concentrates, poor, refractory concentrates are increasingly used in copper production. Hydrometallurgical methods are attractive for processing this raw material. This review analyzes modern hydrometallurgical methods for extracting copper from low-grade concentrates. Research focuses on innovative approaches to increase dissolution rates and profitability of leaching refractory copper sulfide minerals. Solving these problems will optimize Cu extraction and expand hydrometallurgy for various ores, improving efficiency and environmental sustainability. Current studies include atmospheric leaching, bioleaching with bacterial mixtures, and autoclave leaching, with optimization of conditions, reagents, and additives to destroy passivation layers and achieve high extraction from chalcopyrite. Hybrid leaching methods are also being developed, combining advantages of different approaches. Each method has advantages and drawbacks, such as passivation layer formation and by-product utilization (sulfuric acid, sulfur, nitrates, iron, chlorine). Overcoming these difficulties remains a key research direction for effective hydrometallurgy. Advances in this field may offer a competitive alternative to traditional pyrometallurgical processing of low-grade copper concentrates.

This paper presents the results of an investigation of the possibility of the reliable determination of the residual stress–strain state in polymers and composites using a combination of bridge curvature, optical scanning, and finite element methods. A three-factor experiment was conducted to determine the strength of printed PLA plastic products. The effect of the residual stresses on the strength of the printed products was evaluated. By comparing the values of the same strength stresses, a relationship between the nature of the stresses and the strength of the samples was found. A tendency of the negative influence of tensile stresses and the opposite strengthening effect of compressive stresses was obvious, so at the same values of tensile strength, the value of residual stress of 42.9 MPa is lower than that of the fibre compression at the value of 88.9 MPa. The proposed new methods of the residual stress determination allow obtaining a complete picture of the stressed state of the material in the investigated areas of the products. This may be necessary in confirming the calculated models of the residual stress–strain state, clarifying the strength criteria and assessing the quality of the selected technological modes of manufacturing the products. © 2024 by the authors.

Escalating environmental concerns and the depletion of non-renewable resources have intensified interest in sustainable and eco-friendly materials. Cellulose-based hydrogels, renowned for their biocompatibility, biodegradability, and excellent mechanical properties, have emerged as promising candidates for diverse applications, including biomedicine, agriculture, and water purification. This review focuses on methods for extracting nanocellulose from agricultural wastes and their use in creating cellulose hydrogels. Special emphasis is placed on the mechanical, chemical, thermal, and environmental properties of nanocellulose, as well as its applications in packaging materials, medical devices, biocomposites, and filtration systems. The literature review examines cellulose extraction methods, hydrogel properties, and their industrial applications. The key advantages and disadvantages of these methods are identified, and directions for future research are proposed. This work provides a comprehensive overview of the current state of research on cellulose-based hydrogels and contributes to the development of more efficient and sustainable production methods for these materials.

This paper presents the microstructure of composite material, which consists of metal inclusions and polyamide matrix, the data of which were obtained by computer modeling. The investigated composite material is one of the main directions in the production of materials for advanced MIM technologies, which allows to refuse expensive injection molding process and use technological processes of layer-by-layer growing of parts. The simulations were carried out in top level programs like DIGIMAT and NASTRAN/PATRAN. The simulation modeling of composites at the micro level made it possible to establish the relationship between the percentage of inclusions and the upper yield strength of the material and the constituent components of the stiffness matrices. All these can be considered as input data for the study of composite material at the macro level. At the macro level, virtual studies of standard specimens printed from polymer yarns were carried out to determine the strength. The simulations were conducted as layer-by-layer staging experiments, here each printed layer was considered as a layer of composite. © 2024 Author(s).

A mixture of fatty carboxylic acids (FCA) was derived from technical vegetable oil-a residue of sunflower oil production. Chromatographic-mass spectrometric analysis revealed that the mixture primarily consists of nine types of fatty carboxylic acids. Nonionic surfactants (NIS), specifically FCA-PEG esters, were synthesized via esterification of the FCA mixture with polyethylene glycol (PEG) of molecular weights 300, 600, and 1000. The reaction yield was 93–94%. The functional composition of the resulting NIS was determined using IR and NMR spectroscopy. The critical micelle concentration (CMC), surface activity (ability to reduce the surface tension of water), maximum adsorption at the water/air interface, and other parameters of the obtained NIS particles were determined by measuring the surface tension of aqueous solutions. Among the synthesized NIS, FCA-PEG-600 exhibited the highest surface activity (ПСМС = 28.8 mN/m) and maximal adsorption (Гmax =3.0×10-6mol/m2) compared to FCA-PEG-300 and FCA-PEG-1000. This “anomalous” variation in surface activity across the synthesized NIS series can be attributed to the optimal composition (i.e., the optimal hydrophilic-lipophilic balance, HLB) of the FCA-PEG-600 macromolecules. It was found that the obtained FCA-PEG NIS possess flocculating properties. Among them, the macromolecules of FCA-PEG-600 NIS demonstrated the best flocculating ability for bentonite clay suspension particles. Its optimal dosage for flocculation of suspension particles is 0.2 mg/g (200 g/t of dry solids). © The Author(s) 2025. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits the use, sharing, adaptation, distribution and reproduction in any medium or format, as long as appropriate credit to the original author(s) and the source is given by providing a link to the Creative Commons license and changes need to be indicated if there are any. The images or other third-party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

A fatty acid mixture (FCA) was obtained from Technical Vegetable Oil  a Residue of Sunflower Oil production. Mass-spectrometry chromatogram analysis revealed that the mixture consists primarily of nine types of fatty acid. A new cationic surfactant (FCA-3-DMAPA surfactant) was obtained using the amidation reaction of a mixture of FCA with 3-dimethylamine-1-propylamine (3-DMAPA). The chemical structure of the synthesized surfactant was confirmed using mass-spectra chromatogram analysis, IR, 1H-NMR and 13C NMR spectra. The surface-active and colloid-chemical properties of the synthesized surfactant (critical micelle concentration (CMC), wetting of teflon surface, emulsifiering, flocculating and biocidal properties) were studied. The maximal Gibbs adsorption at water/air interface (Гmax = 4.8×10-6 mol/m2), area occupied by one molecule of the cationic surfactant in the saturated adsorption layer (Аmin = 0.35 nm2), surface-activity (ПСМС = 39.8 mN/m) and zeta-potential (zСМС = +71 mV) at CMC were determined. It was established that the obtained cationic surfactant has good wetting, emulsifying, flocculating and biocidal properties.

The SX-EW technology is more effective for the production of copper from refractory oxidized ores for the present day. A wide range of modern extractants is currently offered on the market for the extraction of copper from leaching solutions and its choice is a very important issue in the production of copper using the SX-EW technology. The aim of this work was to study the extraction properties of modified extractants of the Acorga series (5747, 5910, 5640) and unmodified extractant Lix 984N. It has been established that extractants Acorga 5640 and unmodified Lix984 have high selectivity to copper. During the extraction of copper from the productive solution with the use of all extractants, the formation of a third phase, cruda, is observed. Physical and chemical studies have established that the steak contains a large amount of silica, magnetite, hematite and anglesite. The distribution of iron, silica, and copper ions during extraction was studied and it was found that the extractant Lix 984N (10%), then Acorga5640 (10%), has a high selectivity to copper/iron and copper/silica. Acorga 5640 (10%) is an effective extractant of copper from the productive solution of the Almaly deposit. It is observed that the amount of crud formed during extraction also depends on the rate of phase mixing, the number of revolutions of the stirrer, at a speed of 350-450 rpm, the formation of crud is 0.73%. The addition of the Acorga CR60 reagent in the amount of 5-10 ppm leads to a 3-3.2-fold decrease in the volume of the crud

This study proposes a novel computational method, employing the integral dynamics of multibody systems to simulate the transverse vibrations of the rotor in a cantilever-type centrifugal pump. This method was applied to the kinematic assembly of the rotor and its supports, with the latter modeled as springs possessing stiffness and damping properties equivalent to those of real bearings supporting the shaft in an actual design. To investigate transverse vibrations within the system, three key observation points were defined—at the locations of the left and right bearings, as well as at the rotor’s center of mass—to allow for a thorough dynamic analysis. Additionally, the influence of motor rotational speed and the impeller’s eccentricity on the transverse vibrations of the supports and the shaft was examined. The results have revealed that transverse vibrations significantly affect the system’s dynamics at lower rotational speeds, leading to the classification of the shaft as flexible. As the rotational speed increases, the system exhibits enhanced dynamic stability. Furthermore, it was found that for impellers with a diameter less than 300 mm, the unbalanced forces are negligible and can be disregarded in pump design. To reduce vibration levels, an elastic damping ring was selected and incorporated into the system. This novel method provides an effective tool for analyzing the transverse vibrations of centrifugal pump rotors and for optimizing vibration mitigation strategies. © 2025 by the authors.

Niobium commonly occurs as a minor component in Fe–Ti–O oxide systems associated with ilmenite ores and titanium-bearing metallurgical materials, yet its speciation and incorporation mechanisms remain insufficiently resolved. This study investigates the distribution, structural incorporation, and microphase localization of niobium in the Fe–Ti–O system, with emphasis on TiO2-rich domains. Electron probe microanalysis with EDS/WDS, Xray diffraction, thermal analysis, and thermodynamic modeling in HSC Chemistry were combined to characterize niobium-bearing phases in natural and model oxide systems. Niobium was found to occur in two principal modes: as a low-level isomorphic impurity in Fe–Ti oxide matrices and as localized enrichments in TiO2-rich domains, particularly rutile lamellae. A first-order area-based estimate for representative analyzed grains suggests that approximately 60–80% of the detected niobium is associated with the lamellar TiO2 channel. The combined observations are consistent with a sequential mechanism involving isomorphic substitution of Nb in Ti sites, followed by microphase enrichment and segregation into more compositionally distinct niobium-bearing oxide or titanate microphases. In the studied material, integrated mapped-field Nb is about 0.04 wt.%, whereas matrix Nb commonly lies at trace levels of about 0.02–0.05 wt.% under the applied analytical conditions, consistent with low-level background incorporation, whereas locally Nb-enriched rutile-like domains reach about 0.70–1.00 wt.%. TiO2-rich domains are therefore identified as the principal concentrators of niobium in Fe–Ti oxide systems. Taken together, the natural observations, model experiments, and thermodynamic calculations support an integrated mechanistic sequence of Nb evolution in the Fe–Ti–O system: isomorphic substitution→microphase enrichment in TiO2-related domains→segregation into distinct Nb-bearing oxides/niobates. These findings provide a practical framework for interpreting Nb behavior in natural and technological Fe–Ti–O materials

This study explores the synthesis of sorption-active phosphate materials from manganese ore enrichment tailings of the Zhairem deposit. The initial tailings, predominantly composed of calcite (76.4 %), quartz (16.4 %), and braunite, were characterized by XRD and EPMA. Acid-thermal treatment with phosphoric acid followed by calcination at 200-800°C yielded calcium - manganese phosphate materials. Phase transformations were monitored via XRD, showing formation of crystalline phosphates at 200 - 600°C and a glassy phase at 800°C. The product synthesized at 600°C demonstrated the lowest water solubility (9.91 %), highest pore volume (0.175 cm³ g-1), and optimal sorption capacity for Ni2+ (0.2934 mg-eq g-1), which increased to 0.4697 mg-eq g-1 after 0.4 wt. % of HCl activation. The enhanced performance is attributed to the formation of low-solubility polyphosphates and well-developed porous structures. SEM confirmed porous morphology at 600°C and denser, glassy structure at 800°C. The synthesized material showed no toxic elements such as Pb, Cd, or As, making it suitable for environmental applications. The findings indicate that Zhairem tailings are a promising raw material for producing effective sorbents for heavy metal removal, especially after acid activation. The optimal product is the calcium-manganese phosphate synthesized at 600°C.