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Date submitted2023-07-20
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Date accepted2023-10-25
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Date published2024-04-25
Directions in the technological development of aluminium pots
- Authors:
- Еvgenii S. Gorlanov
- Leopold I. Leontev
Directions for the technical and technological development of aluminium industry, existing and promising projects to reduce the energy consumption and the environmental impact are analyzed. The active participation of the state in the organization of financial instruments for the ecological reconstruction of obsolete production facilities is discussed. In spite of the fact that the technology of aluminium pots is developed towards the increase of a single capacity, but with limited potential of reducing energy consumption and greenhouse gases emission, the possibilities for the increase of specific output are practically non-existent. Therefore, such projects like pots, equipped with inert anodes and drained cathodes arise and are under development, the successful completion of which is unlikely after multi-year researches and pilot tests. To continue the works related to inert anodes the decisive answer about the industrial safety of local sources of the massive oxygen emissions to atmosphere is required from competent entities. The drained cathode project, after discussing the existing problems, seems unfeasible. As opposed to the existing technology the development of the pots with vertical electrodes offers great opportunities to the designs of inert anodes and drained cathodes. Positive results of using shaped electrodes, homogenizing their surface and developing the methods for the synthesis of composite cathodes directly during the electrolytic process were obtained in laboratory conditions. It is expected that the combination of these trends and the successive dimensional scaling shall allow using the vertical electrodes at the next level for the fold increase of specific pot capacity and for the decrease of energy consumption and greenhouse gas emissions.
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Date submitted2022-10-19
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Date accepted2023-02-14
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Date published2023-04-25
Electric steelmaking dust as a raw material for coagulant production
The paper describes the issues associated with waste generated during steel production and processing, in particular the dust from electric arc furnaces (EAF). An effective solution for the disposal of such waste is its involvement in processing to obtain valuable products. This paper studies the physical and chemical properties of EAF dust produced during the smelting of metallized pellets and captured by the dust and gas cleaning system of the steel-smelting shop at the Oskol Electrometallurgical Combine, Belgorod Region. The results obtained in the study of the chemical and disperse compositions of dust, the microstructure of the surface made it possible to propose the use of dust as a raw material for coagulant production. The conditions of acid-thermal treatment of dust are determined, contributing to the partial dissolution of iron (II), (III), and aluminium compounds, which ensure the coagulation processes during wastewater treatment. Model solutions show high efficiency (> 95 %) of water treatment from heavy metal ions by modified EAF dust.
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Date submitted2020-06-29
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Date accepted2021-05-21
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Date published2021-09-20
Transformation of grains of technological raw materials in the process of obtaining fine powders
Crushing and grinding of materials are the most common processes of sample preparation for subsequent analysis and industrial application. Recently, grinding has become one of the most popular methods for producing nano-sized powders. This study investigates certain features of grain transformation in the process of grinding ores with finely dispersed valuable components in order to liberate them, as well as specifics of grinding metallurgical raw materials, metals and their mixtures for using them as initial components in metallurgical and other technological processes. We identified and examined structural and morphological changes of various powders after ultrafine grinding using the methods of scanning electron microscopy and X-ray microanalysis. It was proved that in order to take into account sample preparation artifacts during analytic studies of solid samples and development of technological processes, fine grinding of heterogeneous materials, especially if they contain metals, requires monitoring of the ground product by methods of scanning electron microscopy and X-ray microanalysis.
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Date submitted2019-04-04
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Date accepted2019-08-04
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Date published2020-04-24
Chemical heterogeneity as a factor of improving the strength of steels manufactured by selective laser melting technology
The aim of this paper was to establish the causes of the heterogeneity of the chemical composition of the metal obtained by the LC technology. The powdered raw material was made from a monolithic alloy, which was fused by the SLM, the initial raw material was a laboratory melting metal of a low-carbon chromium-manganese-nickel composition based on iron. To determine the distribution pattern of alloying chemical elements in the resulting powder, electron-microscopic images of thin sections were combined with X-ray analysis data on the cross-sections of the powder particles. As a result, it was found that transition (Mn, Ni) and heavy (Mo) metals are uniformly distributed over the powder particle cross-sections, and the mass fraction of silicon (Si) is uneven: in the center of the particles, it is several times larger in some cases. The revealed feature in the distribution of silicon is supposedly due to the formation of various forms of SiO 4 upon the cooling of the formed particles. The internal structure of the manufactured powder is represented by the martensitic structure of stack morphology. After laser fusion, etched thin sections revealed traces of segregation heterogeneity in the form of a grid with cells of ~ 200 μm.
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Date submitted2018-10-28
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Date accepted2018-12-30
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Date published2019-04-23
Development and research of formation technologies on specialized presses with subsequent sintering of high-density details from iron-based powders
- Authors:
- A. M. Dmitriev
- N. V. Korobov
- A. Zh. Badalyan
Creating shifts of the lyaers in a deforming workpieces improves the quality of the product produced by pressure treatment. qual-channel angular pressing and precipitations of a cylindrical billet with a rotating turnaround were developed by specialists earlier and became basic for scientists engaged in nanotechnology. One of the most modern schemes for creating nanostructures by processing on presses is the «Cyclic Extrusion Compression» scheme (in Russia – «Hourglass»), which has significant drawbacks. To date, research on the creation of layer shifts in compacted metal powders is substantially less than in compaction of compact blanks. The article developed compaction schemes for presses of blanks from iron-based powders that have a certain analogy with the «Hourglass», while lacking the disadvantages inherent in the named scheme and implemented on the created samples of specialized hydraulic presses. The results of the studies of density, strength and microhardness before sintering the samples molded from a number of domestic and imported powders on iron base, including those doped with carbon and other alloying components, are described. It has been established that with the use of the formation schemes for powders providing large shifts between particles, the density of the preforms increases on average by 10-12 %. With an average stress (16.32 MPa) of the transverse section of the molded specimen prior to its sintering, molding with shifts between particles increases this stress by 78 %. The strength after sintering of samples made using the compaction schemes developed by the authors of the article increases approximately by 2 times. Magnetic pulse treatment (MPT) of a molded sample prior to its sintering increases its resistance to shearing before sintering, regardless of the molding pattern. When MPT of both the powder and the molded sample is executed, the most uniform distribution of microhardness in the sample is achieved, and after subsequent sintering, the most uniform distribution of the mechanical characteristics of the product. The results of all studies are described by regression equations.
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Date submitted2018-05-06
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Date accepted2018-07-17
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Date published2018-10-24
Obtaining intermetallic compounds in Al–Ti–Zn system
- Authors:
- V. V. Kaminskii
- S. Y. Petrovich
- V. A. Lipin
Binary intermetallic compounds – titanium aluminides (TiAl, Ti 3 Al) – when added to the alloys, significantly increase their strength and special properties. The most promising direction to produce intermetallic compounds are mechanochemical technologies, including mechanical alloy building. Mechanical alloying makes it possible to introduce much smaller particles into the metal matrix than can be achieved using standard powder metallurgy technologies. In addition to mechanical synthesis, aluminum-based intermetallic compounds were produced by self-propagating high-temperature synthesis (SHS) of solid chemical compounds. The synthesis was carried out according to a multistage scheme: preparation of titanium and aluminum powder, mixing; synthesis of the Al 3 Ti intermetallic compound by the SHS method in vacuum followed by mechanical activation of stoichiometric charges. The aim of the research was to study the dynamics of the development of nanodispersed phases in the process of synthesis during mechanical alloying. The power absorbed by the unit mass of the material for different processing times of the charge was calculated. When the level of the specific power (dose) of mechanical treatment was 3.5 kJ/g, the maximum content of intermetallic compound in the resulting material was achieved. Based on calculations and the data obtained during X-ray phase analysis, the dependence of the change in the content of ternary intermetallic compounds in the final product on the absorbed power was determined. As a result of the studies using raster electron microscopy and X-ray analysis, it was found that mechanical alloying of nanostructured intermetallic compounds Ti 4 ZnAl 11 and Ti 25 Zn 9 Al 66 with the size of nanodisperse phases less than 12 nm in the Al–Ti–Zn system, the weight ratio of proportion of the latter reaches 74 %.
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Date submitted2009-08-27
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Date accepted2009-10-25
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Date published2010-02-01
Regularities of change of water-repellent properties of the nanostructured metal powders on the base of aluminium
Regularities of change of water-repellent properties of metal powders on the basis of aluminium depending on the program of nano-structural surface modifying are studyed. The rows of increase of water-repellent properties of modified aluminium on the base of coarse-dispersed and high-dispersed (PAP-2) powders are obtained. Several specimens excelling initial hydrohobic PAP-2 inits water-repellent capacity are found out. The research uses the methods of XP-, EDX- spectroscopy and gravimetry.