Кафедра теоретичних основ металургійних процесів (ДМетІ)

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ENG: Department of Theoretical Foundations of Metallurgical Processes (Dnipro Metallurgical Institute, DMetI)

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Regularities of Solid-Phase Reduction of Iron Oxides under Conditions of Combined Chemical-Catalytic and Energetic Influence
(Ukrainian State University of Science and Technologies, Dnipro, 2025) Grishin, Oleksandr M.; Projdak, Yurii S.
ENG: Purpose. The purpose of the work is a physicochemical analysis of the intensification of the process of solid-phase iron reduction under the conditions of the joint influence of catalytic additives and an electromagnetic field (EMF). Methodology. The experiments were conducted in an alternating magnetic field with a frequency from industrial to ultrasonic using the thermogravimetric method. The process of reduction of various iron ore materials was studied in the temperature range of 873-1373 К Results. The results of laboratory experiments indicate the influence of the electromagnetic field and intensifying catalytic additives on the process of solid-phase reduction of various iron ore materials. The non-additivity of the results of the joint influence of additives and an intensifying EMF is shown. The study of the influence of various process parameters on the rate and degree of reduction of iron ore materials is carried out. Scientific novelty. The joint intensifying effect of catalytic additives and EMF on the process of solid-phase iron reduction is experimentally shown. A physicochemical justification of the non-additivity of the joint influence on the kinetics of the reduction process is proposed. Practical significance. Intensification of the processes of solid-phase reduction of iron ore raw materials provides a significant increase in the productivity of direct iron production technologies - process intensification and process productivity.
Theoretical and Experimental Justification of the Solid-Phase Reduction of Chromium and Iron from Their Oxides
(Iron and Steel Institute of Z. I. Nekrasov National Academy of Sciences of Ukraine, Dnipro, 2026) Stepanenko, Dmytro O.; Grishin, Oleksandr M.; Kuksa, Oleg V.; Lisova, Liudmyla O.; Povorotnia, Iryna R.
ENG: Obtaining high-quality steel grades amid growing shortages of mineral and energy resources poses an important challenge for the metallurgical industry: improving existing technologies and developing new ones for producing alloying materials using substandard ores and waste. Solid-phase reduction (SPR) technology is a promising approach that enables sponge ligatures to be obtained from complex charges at temperatures below their melting points. This reduces energy costs and ensures a lower content of harmful elements in the metal, particularly sulfur and, under certain conditions, phosphorus. The technological features of SPR distinguish it from traditional ferroalloy production processes. This work uses an approach to the thermodynamic study of the Cr-O-C system that reflects the prevailing direction of the solid-phase reduction mechanism of chromium oxide by carbon. In this case, the process mainly occurs in the vapor-gas phase, with the gas phase (CO-CO2) playing a decisive role in connecting the solid reagents. It has been found that further decarburization of products from the solid-phase co-reduction of chromium and iron is possible through additional thermochemical treatment of the reduction product. The reduction of carbon by treating the sponge ligature with a gas mixture of H2 – H2O or Ar – H2O at a temperature of 1273 – 1373 K and H2O concentration of 1 – 2% for 25 – 40 minutes has been scientifically substantiated and experimentally confirmed.