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The blast furnace is the dominant high-temperature reactor in the modern ironmaking industry. Iron oxide in iron ores can be converted to metallic iron through blast furnace smelting, and this high-temperature melting can be used to separate the molten iron from the gangue components. The formation and thickness of the hot-surface slag crust on the copper stave in the high-temperature area of the middle and lower parts of the blast furnace are crucial for the safe operation and long campaign of the blast furnace. To enhance the precision of determining the thickness of the slag crust in this specific region, samples were extracted from the hot surface of the copper cooler situated in the high-temperature area. This extraction was carried out during the maintenance procedure of the blast furnace stockline. Subsequently, the thermal conductivity and melting performance of the slag crust were measured. The slag crust thicknesses corresponding to the various temperature measurement sites of the stave were determined by developing a mathematical model for the heat transfer of the copper stave. The actual slag crust thickness measurement data were acquired while the blast furnace stockline was in operation, and the data were then utilized to corroborate the model’s predictions. A blast furnace with an effective volume of 3200 m3 was used to test the model. The average thickness of the hot-surface slag crust was computed for cases that occurred between 2020 and 2022. The data’s correlations with the blast furnace’s technical and economic indices during the same time period were examined. The findings indicated that the blast furnace’s operation indices improved with a thinner slag crust, but there was also a higher chance of damage to the copper stave’s internal cooling water pipes. Taking into account the technical and economic indices as well as a long campaign of the blast furnace, 150–200 mm is recommended as the appropriate average slag crust thickness on the surface of the copper stave in the high-temperature section.

The relevance of using slag crust separation methods, which are characterized by easy separation and are based on thermodeformation processes in the sample, is shown in the development of new welding materials. The developed method of assessing slag separation based on the theoretical calculation of thermo-deformation processes in the base metal has passed the stages of experimental research The experimental approbation of the proposed methodology for assessing the separation of the slag coating from the surface of welded joints under experimental fluxes based on the TiO2-MnO-SiO2–MgO–CaO-FeO-Al2O3 slag system was carried out for different welding regimes. The evaluation criterion for the high-temperature separation of the slag coating takes into account: the ratio of the geometric parameters of the test sample, the amount of heat input during the surfacing process, and the factor of the presence of spinelforming components at the slag-metal interface. The selected parameters for evaluating the separation of the slag crust in points, where the guaranteed separation of the slag coating is counted for the arbitrary separation of the slag during its destruction or the arbitrary separation of the slag by a monolithic layer. The practical value of the proposed method lies in the possibility of quantitative assessment of the probability of high-temperature separation of the slag coating for a wide range of fluxes for surfacing. The results of the conducted experiments show the efficiency of the developed methodology for evaluating the high-temperature separation of the slag coating from the surface of the weld metal. [ABSTRACT FROM AUTHOR]

The blast furnace is the dominant high-temperature reactor in the modern ironmaking industry. Iron oxide in iron ores can be converted to metallic iron through blast furnace smelting, and this high-temperature melting can be used to separate the molten iron from the gangue components. The formation and thickness of the hot-surface slag crust on the copper stave in the high-temperature area of the middle and lower parts of the blast furnace are crucial for the safe operation and long campaign of the blast furnace. To enhance the precision of determining the thickness of the slag crust in this specific region, samples were extracted from the hot surface of the copper cooler situated in the high-temperature area. This extraction was carried out during the maintenance procedure of the blast furnace stockline. Subsequently, the thermal conductivity and melting performance of the slag crust were measured. The slag crust thicknesses corresponding to the various temperature measurement sites of the stave were determined by developing a mathematical model for the heat transfer of the copper stave. The actual slag crust thickness measurement data were acquired while the blast furnace stockline was in operation, and the data were then utilized to corroborate the model's predictions. A blast furnace with an effective volume of 3200 m3 was used to test the model. The average thickness of the hot-surface slag crust was computed for cases that occurred between 2020 and 2022. The data's correlations with the blast furnace's technical and economic indices during the same time period were examined. The findings indicated that the blast furnace's operation indices improved with a thinner slag crust, but there was also a higher chance of damage to the copper stave's internal cooling water pipes. Taking into account the technical and economic indices as well as a long campaign of the blast furnace, 150–200 mm is recommended as the appropriate average slag crust thickness on the surface of the copper stave in the high-temperature section. [ABSTRACT FROM AUTHOR]

The peculiarities of the process of forming complex compounds, namely, spinels, in flux-cored arc welding for the slag TiO2-MnO-SiO2-MgO-CaO-FeO-Al2O3 system are studied. An experimental investigation of the mechanism of spinel formation in conditions of electrode arc welding and cladding under flux is carried out. Based on the analysis of microimages of the slag surface obtained using scanning electron microscopy, the mechanism of spinel formation, namely, the growth of microcomplex compounds into macrospinels, is presented. The main stages and mechanism of formation of the complex compounds, namely, spinels, are described. As shown, the structure of spinels is determined by the temperature conditions of the crystallization of the slag melt. The study reveals that one of the determining factors of high-temperature separation of the slag crust during multilayer cladding with overlap of the previous layer is the formation of spinels at the interphase boundary between the slag and the metal. Based on modern ideas about the structure of slag melts, a mechanism for the formation of complex compounds at the interphase boundary between slag and metal is proposed. The main factor determining the process of high-temperature separation of the slag coating for the TiO2-MnO-SiO2-MgO-CaO-FeO-Al2O3 system is the formation of complex compounds based on spinel-forming elements and slag oxides at the interphase boundary between the slag and the metal. [ABSTRACT FROM AUTHOR]

The operating conditions influence the stability and consumption of a blast furnace. Recognizing these conditions makes changing the burden distribution parameters more efficient. The cooling stave temperature (CST) is a crucial state parameter that indicates the conditions of the process. Owing to the high data volume of the CST and the lack of methods for recognizing the stability of the slag crust, it is difficult for operators to recognize the conditions accurately according to the CST during the ironmaking process. Thus, in this study, a condition recognition method with information granulation for burden distribution in a blast furnace was presented. First, information granulation was employed to reduce the volume of the CST data and present it in a granular form. Then, considering the lack of a method for calculating the similarity of CST information granules, a novel fuzzy similarity calculation method was devised to calculate the membership grades of information granules belonging to different standard granules. Finally, the conditions were recognized according to the membership values. Experimental results based on industrial data demonstrated that the proposed method can be used to recognizes the conditions in the blast furnace. [ABSTRACT FROM AUTHOR]

Copper staves have been widely applied in large blast furnaces especially those whose inner volumes exceed 2000 m3 due to high cooling capacity. In the past decade, copper staves suffered severe damages in some blast furnaces, which not only shortened their campaign lives, but also caused huge economic losses. In order to make out this phenomenon, the damage mechanism of copper staves was investigated via analyzing the chemical composition, thermal conductivity, metallographic aspects and microstructure in this paper. As a result, the working state was more likely to damage copper staves instead of their materials. At the beginning, the poor quality of the coke and the large bosh angle promoted the development of edge airflow, which intensified the erosion of refractory materials, resulting in the fall-off of slag crusts and damage of cooling water pipes. After repair, the cooling capacity of copper staves still declined, causing the temperature to rise easily; consequently, hydrogen attack happened when the temperature reached 370 °C, which degraded the performance of copper staves. Therefore, copper staves were worn too quickly to form slag crusts, which finally failed under the hydrogen attack and the scouring of the edge airflow at high temperatures.

Proper burden distribution is an important way to improve conditions of a blast furnace, which indicate the stability and energy consumption. However, it is difficult for operators to recognize the stability and energy consumption at the same time and adjust them through burden distribution, due to complex iron-making mechanism. Therefore, this article presents a two-stage decision-making method for the burden distribution parameters based on recognizing the conditions. First, the stability and energy consumption are recognized, respectively, according to the classification of stability of slag crust (SSC) and the gas utilization rate (GUR). And then, two prediction models are presented for the SSC and GUR to predict the conditions. Finally, the burden distribution parameters are determined in two stages, where edge parameters of the burden distribution are determined at first according to the SSC, and then, center parameters are determined according to the GUR. Experimental results based on industrial data show that the proposed method provides an effective decision-making way for improving the conditions. [ABSTRACT FROM AUTHOR]

The study presents the results of the research into the effect of the dynamic properties of inverter and diode power sources of welding arc power supply on the stability of melting and transfer of electrode metal into the weld pool. The principal energy parameters of the power source include the rates of rise and fall of short-circuit current, the ratio of arc burning current to short-circuit current, and other related factors. It has been demonstrated that an increase in the rate of change of these parameters within one welding mode microcycle alters the properties of heat and mass transfer, increases the frequency of electrode metal droplet transfer, reduces the size of transferred droplets in the weld pool and the duration of their stay on the electrode end under the influence of the high temperature of the welding arc, and the duration of short circuits. The increase in the mass fraction of alloying elements at their transition from the coated electrode to the weld metal is demonstrated to depend on the rate of change of the main energy parameters of one welding mode microcycle of the inverter power source in comparison with the diode rectifier. An enhancement in the structural integrity and properties of permanent joints during welding has been observed when using an inverter power source for the welding arc with high dynamic properties. [ABSTRACT FROM AUTHOR]

The article presents the results of the development of a technological method and equipment for the renovation of erosion-worn parts of automotive equipment. In the parts of machines and mechanisms subjected to mechanochemical wear, thin-sheet steel, the specific weight of which in car structures is on average 80%, is especially destroyed, as well as the working organs of machines: threaded joints, welding seams, internal friction surfaces (hubs, bearings, rollers and etc.). The solution to this problem is simplified when surface surfacing is used and it is possible to obtain a relatively flat surface with good separation of the slag crust without sharp height differences in the overlapping area.For welding wear-resistant and corrosion-resistant layers, it is necessary to use wires with a diameter of up to 2 mm, which allow applying thin layers of steel alloyed mainly with Cr, Ni, Mn, Mo during arc welding. The welding of such steels to ensure high quality of the deposited layers from the point of view of achieving high corrosion resistance is quite difficult. This is due to the fact that during the operation of welded parts and even when they are kept for a long time before operation, stripes with low corrosion resistance appear on the welded surface (dark colors on the polished surface of the working layer). In the process of developing the technology of surfacing the surface of worn parts, powders of ultra-fine particles were developed, which were used to fill the core of powder-coated wires with diameters of 1,6 and 2,2 mm. The composition of the charge included exotic additives, in particular chromium, molybdenum and complex liquid and alkaline earth ligatures, in particular yttrium and cerium, which made it possible to significantly increase the wear resistance of the deposited layer.

Ferrous metallurgy has been and remains one of the main types of production activities that enables humanity to extract, process and produce basic equipment for all types of activities. The growth of ore production as well as the reduction in world reserves of the raw material base have lead to the search for effective methods of processing and preparation of waste for metallurgical processing. The mining and metallurgical sector of the Republic of Kazakhstan, which has its an integrated mining and metallurgical complex with its own coal, iron ore, and energy base, uses iron ores from several deposits. It also includes ash and sludge storage tanks, which store valuable metallurgical waste, such as converter production sludge, rolling scale, and others, the use of which is hindered by the presence of certain harmful impurities in the composition (a rather high content of non-ferrous metals, especially zinc, a high content of oils, etc.). These valuable technological wastes require additional research that may contribute to their use as a charge or as iron-containing components of the charge. Based on the urgency of the tasks of dephosphorylation of iron ores and utilization of human-made waste (converter sludge and rolling scale), studies were conducted to try to eliminate existing problems. The results of the research work make it possible to obtain metals based on prepared pellets with a significantly low phosphorus content; this will enable the use of an oiled rolling scale and converter sludge for the production of a metalized product for steel smelting. The resulting metalized products make it possible to dispose of scale and converter sludge by 70%, and the degree of iron extraction exceeds existing methods by 1–3.5% (92.1–94% vs. 95.6%). [ABSTRACT FROM AUTHOR]

The non-destructive full-field non-contact thermographic technique is applied for non-destructive flaw detection of the welded joints, in real-time and offline configuration. In this paper, a thermographic procedure for real-time flaw detection in manual arc welding process is presented. Surface temperature acquisitions by means of an IR camera were performed during arc welding process of 8 specimen both for calibration and validation of the numerical model. The investigated variables are the technique (manual stick arc (SMAW) and gas arc (GMAW) welding) and the joint shape (butt and T joint) for steel joints, in sound conditions and with artificial flaws. Numerical simulation of welding thermal transients was run to obtain the expected surface temperature fields and thermal behavior for different welding parameter configurations. Hardness measurement and micro-graphic analysis were performed to validate numerical simulation results. The real-time thermographic study of the weld pool gives direct indications of anomalies; local studies of the thermal transient and thermal profiles can detect some kind of flaws; microstructural analysis of Heat-Affected Zone (HAZ) and surrounding areas higlights the presence of austenite and martensite distribution which justifies the thermal transients and thermal profiles for different welding configurations. Comparing real-time IR acquisition of the welding process with simulated thermal contours of sound processes provides information of presence of some kind of flaws. Since most of the flaws are generated in the weld pool, it is possible to recognize anomalies directly from the thermal acquisitions or with post-processing the acquired data. [ABSTRACT FROM AUTHOR]

In the process of electroslag remelting (ESR) for large-sized slab ingots, controlling the surface quality of the slab ingot is challenging due to its relatively high width-to-thickness ratio. In this study, a three-dimensional dynamic mathematical model for single-electrode ESR slab ingots was developed using dynamic mesh technology, with the aid of the commercial software FLUENT. The model is based on the electromagnetic field equation, flow field equation, and energy equation. A detailed analysis of various physical fields and the distribution law of the metal pool shape was conducted. According to the calculation results, the maximum flow velocity of the molten slag was found below the consumable electrode, with the range of maximum velocity at different time points varying between 4.35 × 10−2 and 4.88 × 10−2 m/s. The range of the maximum temperature for the slag bath at different time points was between 2118 and 2122 K. As the remelting continued, the impact of the forced cooling of the bottom plate on the temperature of the metal pool weakened. Consequently, the temperature gradient of the electroslag ingot gradually decreased, the depth of the metal pool increased, and the height of the metal liquid head in the metal pool rose. The effects of different voltages, filling ratios, and mold chamfers on the shape of the metal pool were investigated using the established mathematical model. Based on the research findings from the mathematical model, the technical processes for ESR J80 large-sized slab ingots were improved, providing solutions to improve the surface quality of the ESR large-sized slab ingots. [ABSTRACT FROM AUTHOR]

To improve the yield of titanium alloy, a certain amount of TiO2 can be added to the refining slag system of Ti-bearing steel grades. With the aim of understanding the effect of TiO2 addition on the melting behaviors of CaO-SiO2-30%Al2O3-5%MgO refining slags, the melting points of the slags and the phases in the slags are herein studied at different temperatures in the laboratory. It is found that with the increase in TiO2 content (0~10%) in slag, the melting point of the slags drops first, and then rises. The effect of slag basicity (R = w(CaO)/w(SiO2), 2~10) shows a similar tendency. The TiO2 content and slag basicity evidently affect the precipitated phases in the slags at a lower temperature (e.g., 1310 °C). With the increase in basicity, the liquid areal fraction increases first, and then decreases. Moreover, the CaO-TiOx-Al2O3 phase (CTA) and its TiOx content show a declining trend at 1310 °C. When R = 10, large amounts of solid calcium aluminates are precipitated. With TiO2 addition in the slags, the TiOx contents in both liquid and CTA phases increase. Excessive TiO2 addition (e.g., 10%) leads to the large precipitation of CTA, as well. To improve the melting properties of the slag and the yield of Ti alloys during the refinement of Ti-bearing steel grades, a small TiO2 addition (e.g., 5%) may be considered. [ABSTRACT FROM AUTHOR]

Physicochemical properties (viscosity, electrical conductivity, melting point, thermodynamic activity of oxygen) of (10 – 70)CaF2 – (0 – 60)Al2O3 – (0 – 30)TiO2 – (0 – 30)MgO slags system are studied. The required content of titanium in the Inconel 718 (0.65–1.15%) can be provided with the studied slags (49CaF2 – 30Al2O3 – 21TiO2 and 50CaF2 – 22Al2O3 – 18TiO2 – 10MgO) even if they contain 0.5 – 2% SiO2. The aluminum content can be adjusted by adding or pre–increasing its content in the remelting electrode. With temperature growth from 1500 to 2500 K, the equilibrium content of Ti in the metal decreases, and of Al – vice versa. The content of titanium at the initial level (1%) in the molten metal is provided at a temperature of 1700 K with 50CaF2 – 22Al2O3 – 18TiO2 – MgO slag. In comparison with 70CaF2 – 15Al2O3 – 15CaO slag, widely used for superalloy remelting, the studied compositions 49CaF2 – 30Al2O3 – 21TiO2, and 50CaF2 – 22Al2O3 – 18TiO2 – 10MgO will increase environmental friendliness of the remelting as a result of CaF2 content reduction by 20% at comparable values of crystallization temperature and conductivity. [ABSTRACT FROM AUTHOR]

Research into plastic recycling is rapidly increasing as ocean and land pollution and ecosystem degradation from plastic waste is becoming a serious concern. In this study, we conducted a systematic review on emerging research topics, which were selected from 35,519 studies on plastic recycling by bibliometrics analysis. Our results show that research on the biodegradability of plastics, bioplastics, life cycle assessment, recycling of electrical and electronic equipment waste, and the use of recycled plastics in construction has increased rapidly in recent years, particularly since 2016. Especially, biodegradability is the most emerging topic with the average year of publication being 2018. Our key finding is that many research area is led by developed countries, while the use of recycled plastics in the construction sector is being actively explored in developing countries. Based on our results, we discuss two types of recycling systems: responsible recycling in the country where plastic waste is generated and promoting recycling through the international division of labor between developed and developing countries. We discuss the advantages and disadvantages of both approaches and propose necessary measures for sustainable and responsible production and consumption of plastics such as waste traceability system and technology transfer between developed and developing countries. [ABSTRACT FROM AUTHOR]

NiAl-based intermetallic coatings were obtained using non-vacuum electron beam cladding on low-carbon steel. The structure of the coatings was investigated using optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), electron backscatter diffraction (EBSD), and X-ray diffraction (XRD). The coatings mostly consisted of grains elongated perpendicular to the substrates, with a strong <100> texture along the grain growth direction. The coatings contained about 14 at. % Fe, which appeared due to the partial melting of the steel substrate. At the bottom of the coatings, an inhomogeneous mixing zone with an increased concentration of Fe was formed; at the "substrate–coating" interface, a thick layer with a Fe50-Ni25-Al25 at. % composition was observed. The samples exhibited weight gains of 0.1, 0.8, 2.14, and 3.4 mg/cm2 after 100 h of oxidation at 700, 800, 900, and 1000 °C, respectively. The oxide layer contained α-Al2O3 and θ-Al2O3, and the presence of iron atoms contributed to the formation of a small amount of spinel. During the oxidation process, a layer with a high Fe content (~60 at. %) formed along the boundary between the oxide film and the NiAl-based material, which had a positive effect on the formation of a non-porous "oxide–coating" interface. [ABSTRACT FROM AUTHOR]

Flux formulations are specified to target chemical and physico-chemical parameters. Chemical parameters set flux element transfer behaviours and weld metal oxygen contents. Physico-chemical parameters such as slag viscosity, surface tension and melting range are targeted to ensure an acceptable weld bead profile and surface appearance. Slag detachability is an important physico-chemical property required to ensure high welding productivity, smooth weld bead surface and no slag entrapment. Here, bead-on-plate welding tests were made with and without metal powder additions, including aluminium powder as a de-oxidiser. Difficult slag detachability was observed in weld runs made with metal powder additions. Mineralogy of the post-weld slags, and thermochemical calculations, show that the flux was modified due to the aluminothermic reduction of MnO and SiO2 from the slag to form alumina. Increased quantities of spinel phase were identified in the post-weld slag samples, at the weld pool–slag interface. The combined effect of increased slag viscosity, from increased spinel in the slag, and lowered weld pool solidus temperature, resulted in the formation of a rough bead surface morphology, which, in turn, caused mechanical fixation of the slag to the weld bead. Flux modification to higher CaF2 content should ensure that higher quantities of spinel phase can be tolerated in the slag. [ABSTRACT FROM AUTHOR]

The gas utilization rate (GUR) is an important indicator parameter for reflecting the energy consumption and smooth operation of a blast furnace (BF). In this study, the original data of a BF are pre-processed by two methods, i.e., box plot and 3σ criterion, and two data sets are obtained. Then, support vector regression (SVR) is used to construct a prediction model based on the two data sets, respectively. The state parameters of a BF are selected as input parameters of the model. Gas utilization after one hour (GUR-1h), two hours (GUR-2h), and three hours (GUR-3h) are selected as output parameters, respectively. The simulation result demonstrates that using the 3σ criterion to pre-process the raw data leads to better prediction of the model compared to using the box plot. Moreover, the model has the best predictive effect when the output parameter is selected as GUR-1h. [ABSTRACT FROM AUTHOR]

Aphysicochemical analysis was undertaken of fragments of medieval glazed ceramic found at different times in medieval towns located in the Chui, Talas, and Kochkor Valleys of Kyrgyzstan. The samples of glazed ceramic were studied by means of x-ray fluorescence and microscopic analyses. The physicochemical studies of the ceramic glaze from different archaeological complexes on the territory of Kyrgyzstan made it possible to identify the colorants and their features as well as the coloring technology and to note important moments in the historical development of the Gonchar crafts associated with the history of glazed ceramics in the countries of Central Asia. [ABSTRACT FROM AUTHOR]

Viscosity is considered to be a significant indicator of the metallurgical property of blast furnace (BF) slag. However, a BF is a complicated black box so that the measurement of the viscosity has a large hysteresis. A prediction model for the viscosity based on machine learning, principal component analysis (PCA) and k-nearest neighbor (KNN) regression is presented in this article. First, the main influencing factors of the viscosity are analyzed and selected as the input of the model. Then, the two datasets are preprocessed by data normalization. In addition, the sample characteristics of the data are processed to be statistically irrelevant by PCA. Based on the above, the two datasets are applied to the PCA–KNN model and the support vector regression model, respectively. The results show that the predicted result using the PCA–KNN model is more accurate and reaching 99%. [ABSTRACT FROM AUTHOR]

The aim of this investigation is to assess the effect of various additives on coalescence of nickel, copper and cobalt from slags generated during nickel extraction. The analyzed fluxes were silica and lime while examined reductants were pig iron, ferrosilicon and copper-silicon compound. Slag was settled at the different holding temperatures for various times in conditions that simulated the industrial environment. The newly formed matte and slag were characterized by their chemical composition and morphology. Silica flux generated higher partition coefficients for nickel and copper than the addition of lime. Additives used as reducing agents had higher valuable metal recovery rates and corresponding partition coefficients than fluxes. Microstructural studies showed that slag formed after adding reductants consisted of primarily fayalite, with some minute traces of magnetite as the secondary phase. Addition of 5 wt% of pig iron, ferrosilicon and copper-silicon alloys favored the formation of a metallized matte which increased Cu, Ni and Co recoveries. Addition of copper-silicon alloys with low silicon content was efficient in copper recovery but coalescence of the other metals was low. Slag treated with the ferrosilicon facilitated the highest cobalt recovery while copper-silicon alloys with silicon content above 10 wt% resulted in high coalescence of nickel and copper, 87 % and 72 % respectively. [ABSTRACT FROM AUTHOR]

We estimate the potentials of hydrogenation and oxidation of aqueous media, the degree of gas saturation of the weld metal, and the mechanical properties of a welded joint obtained as a result of wet underwater welding with an experimental self-shielding wire. We study the influence of aqueous media on the physicochemical and metallurgical processes in the course of underwater arc welding. We also develop a complex of metallurgical and technological measures aimed at guaranteeing the high quality of joints formed by this kind of welding of 12Kh18N10T corrosion-resistant austenitic steel. [ABSTRACT FROM AUTHOR]

The effect of Na2O and temperature on the thermal conductivity of the Na2O-B2O3 binary system has been measured using the hot-wire method to examine the relationship between the thermal conductivity and structure in high-temperature melts. The thermal conductivity of the binary melt is measured from 1173 to 1473 K in the fully liquid state. The thermal conductivity slightly increases with Na2O content up to 20 wt%. Above 20 wt% Na2O, the thermal conductivity decreases with increasing Na2O. The network structure of molten glass was analyzed using Fourier transform infrared (FTIR), Raman spectroscopy, and XPS. The FTIR analysis shows that 3-D complex borate structures, such as tri-, tetra-, and pentaborate are made by [BO4] tetrahedral units interconnected with 2-D structure boroxol rings in the low Na2O region. Above 20 wt% Na2O content, nonbridged oxygen in [BO2O−] units and diborate groups increase with increase in Na2O. The same tendency is shown by the Raman spectroscopy and XPS analyses. The Raman analysis shows that boroxol rings disappeared with large [BO4] groups, such as tri-, tetra-, and pentaborate structures, which increase at low Na2O content. Isolated diborate groups and nonbridged oxygen in [BO2O−] units increase at high Na2O content. It can be inferred that single structure units, such as isolated diborate groups, interfere with conduction. The XPS analysis results show that free oxygen produced by the interconnection of Na2O in the borate structure does not cause significant changes to O2− in the low Na2O region, but increases the Oo and decreases the O−. Above 20 wt% Na2O, O− slightly increases and Oo shows a decreasing trend. [ABSTRACT FROM AUTHOR]

The specificities of the electroslag remelting process and the structural characteristics of the blocks, manufactured according to the electroslag remelting method, are studied together with the advantages of electroslag remelting (under pressure), as compared to the conventional methods of producing structural steels. Nitrogen solubility in 30Cr2Ni2MoNV steel has been investigated by the levitation melting method. A technology (technological scheme) has been developed for producing 30Cr2Ni2MoNV nitrogen steel on the basis of the diagrams of estimated nitrogen concentration in the liquid state, at a given temperature and pressure. A block of 30Cr2Ni2MoNV steel had been produced using the methods of metallurgy under pressure and its structural parameters: macro structure, density of dendritic structure, volume fraction of dendrites, were studied. Higher density and homogeneity, as well as a trend towards increasing the volume fraction of dendrites and density of dendritic structure, have been established for the nitrogen steel block. [ABSTRACT FROM AUTHOR]

The products of frontal combustion of Fe2O3/TiO2/Al thermite composite powder mixtures with various component ratios are studied. Differences in the composition of the combustion products are discussed. A probable mechanism of their formation is proposed. Practical uses of the results are considered. [ABSTRACT FROM AUTHOR]

A computational-theoretical analysis is made of a system of the required properties of potential materials for use as buffer material in the trap for VVÉR-1000. The analysis points to Al2O3 and Fe2O3 as the main candidates. On the basis of the advantages and disadvantages noted for each of them individually, solid solutions based on Al2O3 and Fe2O3 are of interest for practical applications. Estimates show that taking account of the expected degree of oxidation of zirconium in melt and the volume limitations of the trap, the optimal compositions can be equimolar solid solutions Al2O3–Fe2O3. Estimates are confirmed by experiments investigating the character of the phase diagrams and the interaction of core melt with oxide solutions based on systems Al2O3–Fe2O3. [ABSTRACT FROM AUTHOR]

The effect of acoustic vibrations in the cavitation regime on high-temperature high-viscosity slag melt is evaluated experimentally. It is determined that ultrasonic treatment greatly increases the crystallization power of melt; this could be due to depolymerization of the silicon-oxygen framework of silicate melt and the creation of an extended interface between the gaseous and liquid phases in the melt. It is shown that acoustic treatment promotes dispersion of a refractory solid phase in the melt. [ABSTRACT FROM AUTHOR]

Alkaline nickel-cadmium batteries are among the most used industrial high-power sources. Despite stricter environmental requirements, nickel-cadmium batteries still remain as the main choice for highly reliable power sources for heavy-loaded equipment. Therefore, recovery of cadmium (Cd) from spent batteries is a challenge for the modern recycling industry, particularly as it displays high bio-toxicity. The present study describes a new green approach for Cd recovery from cadmium oxide (CdO). The paper discusses using a ternary chloride composition consisting of calcium, potassium and sodium chloride, thereby avoiding the release of Cd vapour from the reaction volume during the reduction reaction from CdO. For the protective slag layer during the reduction process (which occurs at 650 °C), a 0.515:0.0796:0.405 molar ratio of CaCl2:KCl:NaCl was chosen, with the aim of achieving a melting point at 483 °C. To describe phase and elemental composition of obtained products X-ray diffraction analysis and energy dispersive X-ray spectroscopy, respectively, were applied. Electron and optical microscopy were used for morphological observations. The presence of the metallic Cd was noted. During the reduction reaction, it was noted that slag separated into two parts: a protective upper layer and bottom layer. It was also noted that metallic Cd accumulated with increasing reaction time in the bottom part of the slag. [ABSTRACT FROM AUTHOR]