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Investigation of the possibility of obtaining a complex master alloy used in the deoxidation of steel, smelted from substandard manganese-containing materials, briquettes, and high-ash coals in ore-thermal electric furnaces. Thermodynamic modeling was carried out using the HSC Chemistry software package to determine the optimal process parameters using a second-order rotatable plan (Box-Hunter plan). Thermodynamic modeling improves the understanding of physical and chemical processes, allows making predictions about the behavior of the system under various conditions, optimizing processes and saving time and resources necessary for experiments. Electric smelting of the briquette was carried out with coal and quartzite (to adjust the chemical composition and neutralize residual carbon) in an ore-thermal electric furnace with a power of up to 150 kV*A. The influence of temperature on the equilibrium distribution of silicon, manganese, and aluminum in the «briquette-coal-quartzite» system, the degree of transition of silicon and manganese into a complex ligature and the content of these metals in the alloy are determined by the method of thermodynamic modeling. As a result of experiments on ore-thermal electric smelting of a briquette with high-ash coal, a complex ligature was obtained with an average content of 45.92–53.11% silicon, 27.72–34.81% manganese and 5.60–6.91% aluminum.

The range of all types of ferroalloys is traditionally determined by the requirements of consumers, primarily steelmaking enterprises, as well as the technological capabilities of their pro-duction and the quality of the ore raw materials. Over the past half-century, steel production technology has undergone significant changes, including the transfer of operations for the introduction of ferroalloys for alloying, deoxidation, and refining of steel from melting units to the ladle. This necessitates the development of new ferroalloy compositions with the most favorable physicochemical characteristics for steel processing that account for the lower temperature in the ladle and the limited time for reagent interaction. One of the most widely used and important elements for steel alloying is chromium, which is utilized in the production of both structural and corrosion-resistant grades of steel. In this context, the study investigates the dependence of the physicochemical properties (density, melting temperature, and melting time in liquid steel) of alloys in the Cr–C–Si–Fe system on the chromium and silicon content. It has been demonstrated that increasing the silicon content to 10% and reducing the chromium content from 63 to 53% improves the performance characteristics of ferroalloys, including the following reductions: the crystallization onset temperature from 1620 to 1530 °C, and the density from 7540 to 6800 kg/m 3 . The melting time of high-carbon ferrochrome in steel depends on the Cr content: when the chromium content decreases from 63 to 45%, the melting time of the alloy decreases by 3.1 times, which is mainly due to the decrease in the temperature of the onset of crystallization of the ferroalloy from 1620 to 1570 °C. Chromium-containing ferroalloys are usually introduced into the volume of liquid steel and are slightly prone to corrosion. One of the main characteristics of ferrochrome, from the point of view of their use for alloying steel, is the time of their melting in liquid steel, which is greatly influenced by the melting temperatures of ferroalloys. The speed and degree of assimilation of alloying elements and, accordingly, the duration of extra-furnace steel treatment depend on the melting time of ferroalloys in molten steel, which significantly affects the technical and economic indicators of production. It is not possible to obtain standard grades of ferrochrome containing 63% or more Cr from low-grade chromium ores using existing process flow charts, since these ores are distinguished not only by a low chromium content, but also by a high iron content. High values of the Fe/Cr ratio determine low chromium concentrations in the resulting ferroalloys.

This study presents the results of the solid-state reduction of iron–manganese ore from the Keregetas deposit (Kazakhstan) using hydrogen as a reductant. The findings demonstrate that hydrogen is an effective and environmentally friendly reducing agent, enabling selective reduction of iron. The investigated iron–manganese ore exhibits a complex mineralogical composition comprising oxides of Fe, Mn, Si, and aluminosilicate complex phases. X-ray diffraction (XRD) analysis of the raw ore confirmed the presence of goethite, hematite, quartzite, and MnO2 as the primary mineral phases. Oxidative roasting induced the dehydration of goethite and its conversion to hematite, along with the formation of Mn2O3 and Mn3O4 phases. The detection of Mn7SiO12 indicates interaction between manganese and silica under high-temperature oxidation conditions. Reduction experiments were conducted in an RB Automazione MM 6000 laboratory furnace at temperatures ranging from 700 to 1100 °C, with a holding time of 60 min and a hydrogen flow rate of 0.5 L/min. Results revealed high selectivity of hydrogen reduction: at 700–800 °C, iron and arsenic were predominantly reduced, as evidenced by the emergence of a metallic Fe-containing phase, while oxides of Mn, Si, Ba, and Al remained in the residue. Increasing the temperature to 900–1000 °C resulted in partial reduction of manganese. At 1100 °C, a decrease in the intensity of the metallic phase was observed, likely due to sintering of ore particles and reduced gas permeability. The reduced metal and oxides were readily separable by melting. These findings provide a basis for developing processing schemes for beneficiation and hydrometallurgical treatment of iron–manganese ores from Kazakhstan.

This study presents the results of laboratory experiments on the processing of lateritic nickel ores mixed with coal and CaO, followed by the use of the obtained product for the smelting of nickel-containing ferroalloy by the metallothermic method. The study analyzed the thermodynamic effects of complex reductant concentration (silicon- and aluminum-containing alloy) on the reduction degree of nickel and iron. An experimental process resulted in a product containing Nitotal (2.60%) and Fetotal (60.52%), obtained through reduction roasting of lateritic nickel ore mixed with coal and an addition of 20 g of CaO at a temperature of 1150 °C. Under laboratory conditions, a nickel-containing ferroalloy was successfully obtained using the product after reduction roasting and a complex alloy as the reducing agent. The following optimal process parameters were determined: reductant consumption of 20 g per 100 g of the reduction roasting product, smelting temperature of 1600 °C, and slag basicity (CaO/SiO2) of 0.5. In this case, a nickel-containing ferroalloy with 72% iron, 15% nickel, and up to 5% chromium was successfully obtained through silicon and aluminum reduction using a complex alloy. A microstructural analysis of the nickel-containing alloy was conducted using an electron probe microanalyzer (JXA-8230) in combination with scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results showed that silicon and iron were the dominant elements in all particles. Nickel was detected at concentrations of up to 15.02 wt. %, while chromium reached 3.47 wt. %. Depending on the silicon concentration, the nickel-containing ferroalloy is recommended for corrosion-resistant steel production (Si < 5%) and as a reducing agent for ferronickel production (Si > 5%).

This study investigates the behavior of phosphorus during high-temperature smelting of hydrogen-reduced high-phosphorus oolitic iron ore from the Lisakovsk deposit. The preliminary reduction was carried out at temperatures ranging from 600 to 900 °C using hydrogen, aiming to selectively reduce iron to the metallic phase while retaining phosphorus in the oxide form. The resulting reduced products were subjected to wet magnetic separation and liquid-phase separation. It was found that neither method provides effective separation of phosphorus from iron: phosphorus partially enters the magnetic fraction and, during smelting, transfers into the metallic phase. To confirm the mechanism of phosphate reduction by metallic iron, a control experiment was conducted, in which a mixture of reduced iron and raw ore was smelted at 1650 °C. Microstructural and elemental analyses confirmed the redistribution of phosphorus into the metallic phase. These findings indicate that effective separation of iron and phosphorus cannot be achieved by reduction roasting alone and highlight the need for further studies on slag formation conditions and phase separation kinetics.

This article presents the results of laboratory studies on the smelting of nickel–chromium-containing ferroalloys from low-grade nickel ores from Kazakhstan. X-ray phase analysis was performed on raw materials, which included quartz, nontronite, chromium metahydroxide, goethite, magnetite, iron chromite, and nickel (II) silicate. The reduction reactions of metal oxides with carbon and carbon monoxide were studied as the temperature increased. Experimental smelting was carried out in a Tammann furnace at 1500–1550 °C using three types of reducing agent: RK coke, as well as its mixtures with low-ash Shubarkol coal, in ratios of 75:25 and 50:50. The second option demonstrated the highest economic efficiency, achieving a 91% nickel recovery rate, reduced coke consumption, and a slag-to-metal ratio of 3.07. Chemical analysis showed that the nickel content in the obtained alloys ranged from 2.5% to 6.5%, while chromium content ranged from 2.6% to 4.5%. X-ray phase analysis confirmed the presence of Fe2Ni0.6Si, Fe5Si3, and Fe2CrSi phases in the alloy structure. Local element concentrations varied within the following ranges: Fe—55–59%, Ni—2–10%, Cr—2–7%, and Si—29–35%. The results of this study confirmed the feasibility of producing a nickel–chromium-containing alloy with a nickel content of 2–10% and a chromium content of 2–7%.

This article discusses the development of a technology for producing nickel- and chromium-containing ferroalloy through the carbothermic reduction of low-grade ores from the Batamsha deposit. Thermodynamic modeling of phase formation was carried out using the Chemistry 10 software package, along with a series of pilot-scale smelting experiments in a submerged arc furnace. The influence of technological parameters, particularly slag basicity, on the distribution of nickel and chromium in the alloy was studied. The results of an X-ray phase analysis confirmed the modeling conclusions, revealing the presence of nickel and chromium silicide phases. The proposed technology demonstrated a high metal recovery rate and process stability, indicating its potential for industrial application in Kazakhstan.

The research presented in the article is devoted to the study of the influence of phase compounds on the friability of the Fe-Si-Mn-Al complex alloy. The urgency of the problem lies in the development of technology for producing a non-scatterable alloy from manganese-containing ores and high-ash coals. The main goal of this work is to determine the range of alloy compositions and the resulting phases that affect the dispersibility of the alloy, which is critically important for its industrial implementation. Research methods include thermodynamic diagram analysis (TDA) using data on the standard enthalpy of formation of intermetallic compounds, as well as experimental tests in an ore-thermal electric furnace with a capacity of 200 kV*A. The results show that Fe-Si-Mn-Al complex alloys form a variety of silicide and aluminide phases, including intermetallic compounds and ternary systems, which is critical for understanding and controlling their physicochemical properties. When melting a complex alloy, the content of leboite (Fe3Si7) in the Fe-Si-Mn-Al system plays a significant role. The development of melting process technology will be aimed at avoiding the FeSi2-Fe3Si7-F2(FeAl3Si2)-Mn11Si19 tetrahedron area. This approach to controlling the composition of a complex alloy is critical to ensuring its consistent friability properties in industrial applications. Thus, this work represents an important step in understanding the physical properties and stability of Fe-Si-Mn-Al complex alloys, which have potential for widespread use in metallurgical and other industrial applications.

The paper studies the properties of brass workpieces for antifriction rings under severe plastic deformation by high-pressure torsion. The evolution of microstructure and mechanical properties of deformed workpieces after six cycles of deformation by high-pressure torsion at 500 °C have been studied. All metallographic studies were performed using modern methods: transmission electron microscopy (TEM) and analysis electron back scatter diffraction patterns (EBSD). The deformation resulted in an ultrafine grained structure with a large number of large-angle boundaries. The strength properties of brass increased compared to the initial state almost by three times, the microhardness also increases by three times, i.e., increased from 820 MPa in the initial state to 2115 MPa after deformation. In this case, the greatest increase in strength properties occurs in the first two cycles of deformation.

Reduction of iron in high-phosphorus oolitic ore from the Lisakovsk deposit using solid carbon, carbon monoxide, and hydrogen. An X-ray phase analysis was used to determine the phase composition of the samples after reduction roasting. When reduced with carbon monoxide or hydrogen, α-iron appears in the samples, while phosphorus remains in the form of iron, calcium, and aluminum phosphates. After roasting with solid carbon, phosphorus is reduced from iron and calcium phosphates and migrates into the metal but remains in aluminum phosphate. A micro X-ray spectral analysis showed that at a temperature of 1000 °C and a holding time of 5 h, during reduction with solid carbon, the phosphorus content in the metallic phase reaches up to 7.1 at. %. When reduced with carbon monoxide under the same conditions, the metallic phase contains only iron, and phosphorus is found only in the oxide phase. When reduced with hydrogen at 800 °C, phosphorus is almost absent in the metallic phase, but at 900 °C, phosphorus is reduced and its content in the metallic phase reaches 2.1 at. %.