Browsing by Author "Volkova, Olena"

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Characterization of Thermophysical Properties and Crystallization Behavior of Industrial Mold Fluxes
(MDPI, Basel, Switzerland, 2025) Bellé, Matheus Roberto; Yehorov, Anton; Chebykin, Dmitry; Zotov, Dmytro; Volkova, Olena
ENG: This study explores the thermophysical properties and crystallization behavior of two industrial Mold Fluxes (MF1 and MF2) used in continuous steel casting. Viscosity, density, and surface tension were measured using the Rotating Bob Viscometry (RBV) and the Maximum Bubble Pressure (MBP) method, while crystallization dynamics were assessed via the Single Hot Thermocouple Technique (SHTT). Both fluxes showed temperature-dependent viscosity with distinct break temperatures influenced by chemical composition. MF1 had higher viscosity and activation energy (127.72 kJ mol−1) than MF2 (112.11 kJ mol−1) due to its higher Al2O3 content. Density and surface tension decreased linearly from 1523 to 1623 K, with values of 2642–2618 kg m−3 and 299–291 mN m−1 for MF1, and 2708–2656 kg m−3 and 348–305 mN m−1 for MF2. Crystallization analysis showed that MF1 required higher cooling rates (critical cooling rates: 21 K s−1 vs. 18 K s−1 for MF2) for glass formation, highlighting its greater glass-former content.
Influence of an Electromagnetic Field on Direct Reduction of Iron Oxide Using Hydrogen as a Reducing Agent
(Wiley-Blackwell, USA, 2026) Levchenko, Mykyta; Gryshyn, Oleksandr M.; Velychko, Oleksandr H.; Grek, Oleksandr S.; Nadtochiy, Anzhela A.; Volkova, Olena
ENG: This work investigates the effect of electromagnetic fields (EMF) of varying frequencies on the reduction process of iron oxides and industrial iron ore in a hydrogen atmosphere using thermogravimetric analysis. Both extremely low-frequency (50 Hz) and middle-frequency (25 kHz) EMFs were found to increase the reduction degree and accelerate the reduction reaction compared with experiments without EMF. The application of extremely low-frequency EMF did not cause additional thermal heating of investigated samples. However, with middle-frequency EMF, heating of charged material was observed, which was effectively compensated for by the furnace's automatic power regulation. Experiments with industrial iron ore confirmed that EMF application had a positive effect on reduction process even above the Curie temperature, indicating that the effect is not governed by magnetic properties of iron. These findings demonstrate that EMF-assisted hydrogen reduction can enhance reaction kinetics and reduce hydrogen consumption, offering a promising pathway toward more energy-efficient and sustainable steelmaking.
Phosphorus Partition in an Industrial Basic Oxygen Furnace Process in Ukraine
(Wiley-VCH GmbH, Weinheim, 2024) Volkova, Olena; Tinkova, Nataliia; Onaa, Rapuruchukwu Ifeyinwa; Neubert, Lukas; Niziaiev, Kostiantyn H.; Zotov, Dmytro
ENG: Phosphorus partition data from Ukrainian integrated steel plants are analyzed, focusing on the influence of parameters such as the basicity (CaO/SiO2), optical basicity, tapping temperature, and the contents of (FeO), (MgO), and (Al2O3) in the slag. It is found that the phosphorus partition decreases with increase in tapping temperature and increases with the optical basicity. An increase in the phosphorus partition (P)/[P] followed by a decrease with increase of (CaO/SiO2) are observed. It is found that the optimal value, break point at which phosphorus partition changes its dependence to opposite, has a direct dependence on tapping temperature. At (CaO/SiO2) = 1.9–2.1, (P)/[P] increases linearly with increasing (FeO). However with higher value of (CaO/SiO2) the breaking point when (P)/[P] starts to decrease with increase in (FeO) is noticed. Thereby the optimal value of (FeO) decreases with increasing tapping temperature. In case of (Al2O3) there is only decreasing of (P)/[P] with all (CaO/SiO2) and tapping temperatures. Moreover, the effect of (MgO) varies with (CaO/SiO2). These industrial results are supported by thermodynamic simulations using FactSage 8.1 and aligned with existing results from the literature.