This study explored the feasibility of the carbon-free smelting of ferrochrome (FeCr) using a complex reducing agent—ferroaluminosilicalcium alloy (FeAlSiCa)—produced from industrial waste and ferrosilicochrome (FeSiCr) dust. Laboratory-scale smelting experiments were conducted with Cr concentrate and the addition of FeAlSiCa and FeSiCr dust under four different reducing agent contents: (1) 10% deficiency, (2) stoichiometric amount, (3) 10% excess, and (4) 20% excess. It was found that with a 10% excess, a nearly complete reduction of Cr₂O₃ was achieved (residual content in slag ≤ 0.9%), resulting in the formation of low-carbon FeCr (LC FeCr) with a high nitrogen content (up to 2.6%). Based on a thermodynamic analysis of the reduction reactions, the high reactivity of the FeAlSiCa and FeSiCr components (Ca, Al, and Si) at 1500 °C was confirmed. These reactions were exothermic, which demonstrates the energy efficiency of using these ferroalloys as reducing agents in FeCr smelting. The resulting slag is structurally stable and does not disintegrate over time, making it a promising candidate for potential reuse as a secondary raw material. The results demonstrate the promise of the proposed technology for both reducing the carbon footprint of ferroalloy production and lowering the cost of the metallothermic production of LC FeCr.

This study investigates the feasibility of producing low-carbon FeCr via metallothermic smelting of Cr concentrate and chromite spinel powder using a complex FeAlSiCa alloy as the reductant in an induction furnace. The proposed approach offers an alternative to conventional carbothermic and oxygen-blown technologies, reducing both the carbon footprint and airborne emissions. Three charge compositions were tested with varying FeAlSiCa additions (12, 14, and 16 kg per 100 kg of Cr source) and partial replacement of Cr concentrate with up to 20% CSP. Thermodynamic and microstructural analyses were conducted, and the effects of the slag basicity, temperature profiles, and holding time were assessed. In optimal conditions, Cr recovery reached up to 80% with minimal Cr₂O₃ losses in slag, and the resulting alloys met ISO 5448-81 requirements for nitrogen-containing low-carbon FeCr. Microstructural examination revealed the formation of Fe-Cr solid solutions and CrN phases, with V incorporation from the FeAlSiCa alloy. The process proved stable and energy-efficient, producing compact, non-disintegrating slag. This study highlights the potential of induction furnace smelting and chromite spinel powder valorization as a sustainable path for FeCr production.

The article presents the results of large-scale laboratory tests carried out in the conditions of the Chemical and Metallurgical Institute named after V.I. Zh. Abishev on the use of briquetted mono-charge in the smelting of carbon ferrochrome on a 250 kVA furnace. The purpose of these studies was to determine the technological parameters of the use of briquetted mono-charge containing in its composition chrome ore, wastes from the production of high-carbon ferrochrome, middlings and various carbonaceous reducing agents. The main idea of using these briquettes was to multiply the contact surface of the reductant and ore, which should speed up the technological process. The principal possibility of smelting a standard alloy using briquetted mono-charge is shown. The alloy for individual charge options meets the requirements of the standards. In comparison with the technology without the use of briquettes, the mono-charge technology has shown advantages in all main parameters. The technology with the use of briquettes from the dust of the AktZF gas cleaning system is distinguished by a low yield of non-standard metal and slag, the bulk of the material goes into the gas collection system. Technologies from briquettes from fines pellet production area of Donskoy ore mining and processing plant and flash have very low specific technical and economic indicators and cannot be recommended for industrial use. Improvement of briquetting modes and technology of their smelting is required. The technical and economic indicators were higher than the current one, showed briquettes from ore and coke of the People's Republic of China, briquettes of ore from borlin and shubarkol coals of Kazakhstan.

The article presents the results of a study of phase transformations occurring during gradual heating of briquetted mono-charge. A complex of physical and chemical studies aimed at establishing the possibility of monocharge use for smelting of standard carbon ferrochromium was carried out in the laboratorial conditions on the basis of the Chemical and Metallurgical Institute named after Zh. Abishev. In order to study the phase transformations occurring in a mono-charge for smelting of high-carbon ferrochromium, thermograms of chromium briquettes of different variants were obtained in air oxidizing atmosphere and nitrogen inert atmosphere. Among them the following variants are mentioned: chromium fines mixed with a reducing agent, option I - Shubarkol coal; option II - Borlinsky coal; option III - China coke; as well as option IV - pure dust from Aktobe ferroalloy plant gas cleaning; option V - dust from pellet production site at Donskoy GOK with China coke and option VI - flash from production of briquettes with China coke. As a result of processing of thermograms, the peak temperatures and temperature intervals of behaviour of the thermal effects of chromium oxide interaction with used reducing agents were established. The method of differential thermal analysis (DTA) is based on the most important properties of a substance which are related to its chemical composition and structure and are reflected in the thermal changes of a substance when heated. The reason for the widespread use of this method of non-isothermal kinetics is that one experiment can determine all the kinetic constants, including the activation energy. Analyzing the calculated data on the activation energy, it is possible to assume the diffusion nature of inhibition of the reduction reaction for all studied chromium ore materials. Based on the values of the activation energy of the process, briquettes with Borlinsky coal and complex reducing agent have the highest reducibility. This research was funded by the Committee of science of the Ministry of education and science of Kazakhstan Republic (Grant No. AP14871610).

This study investigates the possibility of producing a complex W–Mo–Cr-containing alloy via metallothermic reduction of oxide concentrates in the presence of direct reduced iron (DRI) in an induction furnace under atmospheric conditions. A complex FeAlSiCa alloy was used as a reductant due to its high exothermicity and combined reducing potential. Thermodynamic analysis showed that the reduction of WO₃ and MoO₃ is more favorable compared to Cr₂O₃, which is reflected in the temperature profiles of the process. Experimental results confirmed that the addition of FeAlSiCa leads to intensive exothermic reactions and promotes melt formation. The estimated apparent recovery of W and Mo reached up to ~99%, while Cr estimated apparent recovery remained lower (up to ~70%) due to its higher thermodynamic stability and kinetic limitations. Microstructural analysis revealed a heterogeneous structure consisting of an Fe-based matrix and W–Mo-rich phases, including characteristic “fishbone” morphologies. An increase in reductant amount led to higher Si content in the alloy, indicating the need for composition optimization. The results demonstrate the feasibility of direct complex alloying as an alternative to conventional ferroalloy-based methods and highlight the potential for developing resource-efficient and low-carbon metallurgical technologies.

В статье представлены результаты экспериментов по разработке технологии получения молибден- и вольфрамсодержащих лигатур методом восстановления оксидов тугоплавких металлов в условиях индукционной плавки. В качестве сырья использованы молибденовый концентрат и оксид вольфрама, восстановителем выступал высокоактивный ферроалюмосиликокальций (ФАСК). Температурный контроль осуществлялся с использованием вольфрам-рениевой термопары, зафиксированы экзотермические пики, отражающие стадии восстановления. Получены опытные образцы лигатур и шлака, проведен химический анализ. В лигатурах зафиксировано содержание до 56% Mo и W. Результаты подтверждают высокую эффективность восстановительного процесса и технологическую перспективность подхода. Отмечена возможность оптимизации параметров плавки и состава шихты с целью увеличения выхода целевого продукта и снижения энергозатрат Мақалада индукциялық балқыту жағдайында отқа төзімді металл оксидтерін тотықсыздандыру әдісімен молибден және вольфрамы бар лигату- раларды алу технологиясын әзірлеу бойынша эксперименттердің нәтижелері келтірілген. Шикізат ретінде Молибден концентраты мен вольфрам оксиді пайдаланылды, тотықсыздандырғыш жоғары белсенді ферроалюмосиликокальций (ФАСК) болды. Температураны бақылау вольфрам-рений термопарасын қолдану арқылы жүзеге асырылды, қалпына келтіру кезеңдерін көрсететін экзотермиялық шыңдар тіркелді. Лигатуралар мен қождардың тәжірибелік үлгілері алынды, химиялық талдау жүргізілді. Нәтижелер қалпына келтіру процесінің жоғары тиімділігін және тәсілдің технологиялық перспективасын растайды. Мақсатты өнімнің шығымдылығын арттыру және энергия шығынын азайту мақсатында балқыту параметрлері мен шихта құрамын оңтайландыру мүмкіндігі атап өтілді The article presents the results of experiments on the development of a technology for producing molybdenum- and tungsten-containing ligatures by reducing refractory metal oxides under induction melting conditions. Molybdenum concentrate and tungsten oxide were used as raw materials, and highly active ferroalumosilicocalcium (FASC) was used as a reducing agent. Temperature control was carried out using a tungsten-rhenium thermocouple, exothermic peaks reflecting the stages of reduction were recorded. Pilot samples of ligatures and slag were obtained, and chemical analysis was carried out. The content of up to 56% Mo and W was recorded in the ligatures. The results confirm the high efficiency of the reduction process and the technological prospects of the approach. The possibility of optimizing the melting parameters and the composition of the charge in order to increase the yield of the target product and reduce energy costs is noted molybdenum, tungsten, ferroaluminosilicocalcium, induction melting, exothermy, refractory metal, silicon-aluminum reducing agents