The article presents the results of a study on the production of a complex chromium–manganese–silicon-containing ferroalloy in a large-scale laboratory ore-thermal furnace using man-made waste—chromium-containing aspiration dust obtained during smelting of high-carbon ferrochrome, fines (−5 mm) of iron–manganese ore currently stored in landfills, and finely dispersed coal sludge formed during enrichment. A single-stage technology for the production of a new complex chromium–manganese–silicon-containing ferroalloy by carbothermal reduction is proposed. A metallurgical assessment of the initial charge materials was carried out by the X-ray diffraction (XRD) phase analysis, and metal samples of the obtained ferroalloy were studied by scanning electron microscopy (SEM) in combination with energy dispersive spectroscopy (EDS). The resulting ferroalloy has a complex microstructure with a predominance of carbide and intermetallic phases. A high degree of extraction of chromium (up to 80%), manganese (up to 75%), and silicon (up to 35%) was recorded. The average chemical composition of the obtained ferroalloy, wt.%: Cr—37.41; Mn—17.31; Si—11.84; C—3.81; P—0.14; S—0.02. The slag formed during the smelting of the ferroalloy has satisfactory technological properties: it is characterized by good fluidity, and it actively exits the furnace by gravity. Entanglement of metal kings in the slag is not observed. The results obtained confirm the technological feasibility of the utilization of technogenic raw materials for the production of complex ferroalloys of the FeCrMnSi type.

This study investigates the feasibility of producing an Fe-Cr-Mn complex alloy through the recycling of technogenic wastes from metallurgical operations. The feed materials comprised chromium-bearing dust collected from the gas-cleaning system of high-carbon ferrochrome production, iron–manganese ore fines (<10 mm) from the Tur deposit (Kazakhstan), and coal sludge used as a carbonaceous reducing agent. Thermodynamic modeling of the carbothermic reduction of Cr and Mn oxides and the predicted distribution of components among the metal, slag, and gas phases were performed using the HSC Chemistry 10 software package over a high-temperature range. At 1800 °C, the calculated chemical composition of the target alloy was as follows (wt.%): Cr-35.84, Mn-24.47, Si-16.25, Fe-22.63, and C-0.82. To validate the modeling results, experimental smelting trials were carried out in a 100 kVA electric arc furnace, producing both metallic and slag phases. The average composition of the metal phase was (wt.%): Cr-37.17, Mn-14.46, Si-11.48, Fe-33.23, C-3.48, P-0.15, and S-0.021. The experimental results indicate the formation of a Cr-Mn alloy with elevated Cr and Fe contents and a noticeable C level, confirming the carbothermic nature of the reduction reactions. The composition and microstructural features of the smelting products were examined by scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM/EDS). The findings demonstrate that the combined use of technogenic raw materials and a carbonaceous reductant enables the production of a Cr- and Mn-enriched metallic phase under satisfactory slag-forming conditions. Overall, the results confirm the potential of a resource-saving approach for valorizing fine technogenic wastes in the production of complex ferroalloys and for improving the recovery of target elements through optimization of the charge composition and smelting parameters.

In this paper, the research is devoted to sintering of ferruginous sand – waste from alumina production. The research allowed us to determine the optimal process parameters for obtaining iron ore and fluxed agglomerate. When studying the effect of flux additives in the composition of the agglomeration batch, we considered them from the position of multicomponent oxide systems based on the phase diagrams of the FeO-CaO-Fe2O3-Al2O3, FeO-MgO-Fe2O3-Al2O3 and FeO-MgO-CaO-Fe2O3 systems. The thermal transformations in the ferruginous sands under study and the agglomerate obtained from them were studied. The obtained derivatograms indicate the complexity of the mineral composition of the iron ore materials under study. According to the X-ray phase analysis, wustite FeO and magnetite Fe3O4 are recorded during agglomeration. Also, X-ray phase analysis reveals the appearance of hercynite FeAl2O4 and provides recommendations for avoiding undesirable factors of the formation of low-melting phases from the position of the oxide system FeO-MgO-CaO-Fe2O3. The results of the study are confirmed by the presented X-ray phase and petrographic studies.

This article presents the results of thermodynamic modeling of the process of smelting chromium-manganese-silicon-containing ferroalloy from technogenic raw materials of Kazakhstan. Thermodynamic modeling of chromium-manganese-silicon-containing ferroalloy was carried out using the HSC Chemistry 6 software package (Outokumpu, Finland), based on the principles of minimizing the Gibbs energy and thermodynamic variational principles. Thermodynamic analysis for modeling the process of smelting a complex alloy was carried out in the temperature range from 500 to 2000 ℃ for four real charge compositions (with a 5% deficiency of solid carbon, with a normal course of the regime, and with an excess of solid carbon of 5% and 10% of the stoichiometry). The mechanism of combined carbothermic reduction of silicon, manganese, chromium and iron was studied using the Fe-Cr-Mn-Si-Al-Ca-Mg-C-O system. The calculations performed allowed us to fully study all the physicochemical processes occurring during smelting of chromium-manganese-silicon-containing ferroalloy using the carbothermic method. Based on the thermodynamic data, the optimum consumption of solid carbon per 100 kg of charge (chromium and manganese dust) was determined to be 10.75 kg. The chemical composition of the ferroalloy at 1800 °C is, %: Cr - 35.84; Mn - 24.47; Si - 16.25 and Fe - 22.63. Keywords: complex ferroalloy, carbothermic process, chromium-manganese-silicon-containing ferroalloy, thermodynamics, reduction.

The depletion of global reserves of high-quality sulfide nickel deposits, coupled with the steady growth of nickel demand, has led to increased interest in the processing of oxidized (lateritic) nickel ores, including deposits with significant resource potential in the Republic of Kazakhstan. This paper provides an overview of global nickel ore reserves and their distribution, as well as the major nickel deposits in Kazakhstan, which are primarily located in the Aktobe, East Kazakhstan, Kostanay, and Pavlodar regions. Pyrometallurgical processing routes for lateritic nickel ores are also considered. Conventional production technologies, including the Rotary Kiln–Electric Furnace (RKEF), Krupp–Renn process, blast furnace smelting, Vaniukov process, and ISASMELT process, are reviewed, and their process flow diagrams are presented. These methods typically process lateritic nickel ores containing more than 1.2% Ni, whereas Kazakhstan ores are characterized by lower nickel grades, generally in the range of 0.75–1.1%. The advantages and limitations of conventional processing routes are analyzed, and the factors limiting the effective beneficiation of lateritic nickel ores using traditional methods are identified. The present study substantiates the feasibility of producing nickel-containing alloys from lateritic nickel ores using a metallothermic reduction approach. This method is based on the reduction of nickel and iron oxides using metallic reductants, which enables more selective extraction of target components and the formation of alloys with controlled composition. Metallothermic reduction is of particular interest for the processing of low-grade lateritic ores, as it allows the production of nickel-containing alloys without prior beneficiation, at lower energy consumption, and with reduced sensitivity to variations in the chemical and mineralogical composition of the raw materials. Therefore, this approach is considered a promising direction for the processing of lateritic nickel ores in Kazakhstan.