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Item Модифікація властивостей кам’яновугільного електродного пеку(Український державний хіміко-технологічний університет, Дніпро, 2023) Старовойт, Анатолій Григорович; Малий, Євген Іванович; Чемеринський, Михайло Сергійович; Старовойт, Марія АнатоліївнаUKR: Розглянуто використання електродного пеку як зв'язуючого матерiалу та способи оброблення його з метою полiпшення експлуатацiйних властивостей як електродного матерiалу. Існуючi способи модифiкацiї електродних пекiв не достатньою мiрою забезпечують формування властивостей електродних мас та, вiдповiдно, експлуатацiйних характеристик самообпалювальних електродiв. Tому було запропоновано технологiчний прийом, спрямований на полiпшення цих властивостей шляхом його модифiкацiї поверхнево-активною речовиною. Модифiкацiя поверхнево-активною речовиною дозволила встановити структурно-хiмiчну модифiкацiю електродних мас, оцiнюючи по структурним змiненням основнi характеристики та фiзико-хiмiчнi властивостi, що визначають їх поведiнку в процесi карбонiзацiї робочого кiнця самообпалювального електрода. Як поверхнево-активну речовину застосовували фенолформальдегiдну смолу. Результати дослiдження показали, що використання фенолформальдегiдної смоли як модифiкатора електродного пеку дозволило знизити питомий електроопiр вуглецевих мас на 11% i пiдви- щити межi мiцностi на розрив на 9% за рахунок змiни дифузiйних властивостей в системi «наповнювач–зв'язуюче». Встановлено, що модифiкатор сприяє iнтенсифiкацiї процесiв асоцiацiї надмолекулярних речовин (графiтосом) i виявлено взаємозв'язок мiж реологiчними показниками та рацiональним складом полiдисперсної системи органiчної маси пеку. Запропоновано додавання модифiкатора у кiлькостi до 2% за рахунок середньотемпературного пеку марки Б1 у складi вуглецевих мас. Це дозволило зменшити використання середньотемпературного пеку, покращити експлуатацiйнi властивостi вуглеграфiтових виробiв та знизити навантаження на навколишнє середовище.Item Investigation into the Effect of Multi-Component Coal Blends on Properties of Metallurgical Coke via Petrographic Analysis under Industrial Conditions(MDPI, 2022) Kieush, Lina; Koveria, Andrii; Schenk, Johannes; Rysbekov, Kanay; Lozynskyi, Vasyl; Zheng, Heng; Matayev, AzamatENG: The coalification rank of the coal blend components and their caking properties initially impact the coke’s quality. In part, the quality of coke depends on the technological parameters of the coke production technology, such as the method of blend preparation, the coking condition, the design features of the coke ovens, and the technique used for post-oven treatment. Therefore, to improve the coke quality, the main attention is paid to the quality of the coal blend. The petrographic analysis is the simplest and most reliable way to control coal quality indicators under industrial conditions. In this paper, the effect of nine industrial blends on coke quality using petrographic analysis has been studied. Additionally, this paper addresses the efficient use of coals and the preparation of coal mixtures under industrial conditions, which contributes to the sustainability of cokemaking. For the preparation of blends, 17 coals were used, for which, in addition to petrographic and proximate analyzes, the maximum thickness of the plastic layer was determined. Industrially produced cokes were analyzed for coke reactivity index (CRI), coke strength after reaction with CO2 (CSR), and Micum indices (M25 and M10). It has been established that the petrographic properties of coal blends are reliable parameters for assessing the quality of coke under conditions of an unstable raw material base, multi-component blends, and changes in coking regimes. Moreover, the research results have shown that to ensure the rational use of coals in the preparation of coal blends to achieve the required coke quality and consequently the sustainability of cokemaking, it is necessary to consider not only the mean reflectance of vitrinite but the proximate and caking properties of coals.Item Study of Cellulose Additive Effect on the Caking Properties of Coal(Dnipro University of Technology, Dnipro, Ukraine, 2023) Koveria, Andrii; Kieush, Lina; Usenko, Andrii Yu.; Sova, ArtemENG: Purpose. The work aims to study the effect of cellulose on the caking properties of various types of coking coal used in coking blends. The change in caking abilities has been analyzed to achieve the aim using standard techniques. At the same time, the effect of biomass additives on the plastic properties of coal has been analyzed comprehensively; the optimal amount of additive for practical purposes has been determined. Methods. Multiple coal characteristics in the plastic stage have been studied using a dilatometric method, the enhanced swelling pressure method, the plastometric method, and the Roga index test. The first three methods make it possible to characterize the caking properties of coal; and the Roga index test characterizes its coking ability. Findings. It has been identified that the optimal amount of biomass additive to study the effect on the properties of coal in the plastic state is more than 5 wt. %. In the paper, experimental dependences of the 5 wt. % cellulose addition influence on the caking properties of four coal grades have been obtained. The results showed a slight decrease in caking properties in terms of swelling, swelling pressure, thickness of the plastic layer, and caking ability. Simultaneously, the most sensitive methods for assessing the effect of cellulose addition on the coal plastic properties are the dilatometric method as well as the enhanced method for the swelling pressure determination. Originality. A comprehensive study of the effect of pure cellulose as a component of lignocellulose biomass on the properties of different coal grades in the plastic state (i.e. caking prperteis) has been carried out. A slight change in the coal properties in the plastic state with adding 5 wt. % cellulose, decreasing caking properties, has been shown. An important, not previously reported, conclusion is that the cellulose additive does not have any noticeable effect on the physical properties of the coal charge owing to its loose structure. Practical implications. A slight change in the caking properties of coal has been established with the addition of 5 wt. % which is of practical importance for the preparation of coal blends, and the coke production in the cases of using additives of lignocellulosic biomass without losing its quality. Additionally, renewable additive use while obtaining fuels and reducing agents is an approach to mitigate the negative environmental impact.Item Дослідження особливостей модифікації електродного пеку фенол-формальдегідною смолою(НМетАУ, Дніпро, 2022) Малий, Євген Іванович; Чемеринський, Михайло СергійовичUKR: Мета. Дослідження фізико-хімічних процесів, що проходять між розплавленим пеком і модифікатором – фенол-формальдегідної смоли, та запропоновані фактори регулювання процесу модифікації. Методика. Дослідження модифікації електродного пеку фенол-формальдегідною смолою проводили з використанням методів математичного моделювання, визначення групового складу, сорбційної ємності термоантрациту, зміни крайового кута та індексу змочування. Результати. Визначено, що фенол-формальдегідна смола здатна впливати на реологічні характеристики електродного зв’язуючого. Наукова новизна. Вперше показано, що при технологічному формуванні групового складу пеку під впливом фенол-формальдегідної смоли відбувається його пластифікація, а найбільш дієвим фактором регулювання процесу модифікації є термічна витримка та вміст модифікатору. Практична значущість. За результатами роботи встановлено, що модифікація електродного пеку фенол-формальдегідною смолою позитивно впливає на його властивості, а отримані параметри процесу можливо використовувати під час виробництва вуглеграфітових виробів.Item Дослідження властивостей електродних пеків(НМетАУ, Дніпро, 2022) Малий, Євген Іванович; Чемеринський, Михайло Сергійович; Старовойт, Марія АнатоліївнаUKR: Мета. Дослідження фізико-хімічних процесів, що проходять між розплавленим пеком і твердими наповнювачами – компонентом графітованих електродів, та запропоновані методи визначення реологічної поведінки пеку. Методика. Дослідження реологічної поведінки пеку проводили з використанням методів зміни крайового кута змочування, а поверхневі властивості пеку – з використанням методики прямого визначення індексу змочування. Результати. Визначено, що крайовий кут змочування не може бути абсолютним показником його якості, оскільки він залежить від адгезійної активності пеку з вуглецевими наповнювачами. Наукова новизна. Вперше показано, що характеристики міцності графітованих електродів обумовлюють такі фактори, як індекс змочування, крайовий кут змочування, і залежать від початкового періоду адгезійної взаємодії електродного пеку з вуглецевими наповнювачами. Практична значущість. За результами роботи встановлено, що певний показник відповідає загальному принципу явищ, що відбуваються при змочуванні, що дає можливість повноцінніше охарактеризувати поведінку електродних пеків під час виробництва графітованих виробів.Item Effect of the Quality Indices of Coal on Its Grindability(Dnipro University of Technology, Dnipro, Ukraine, 2022) Miroshnichenko, Denis; Koval, Valentine; Bogoyavlenska, Olena; Pyshyev, Serhiy; Malyi, Evgen I.; Chemerinskiy, Michael S.ENG: Purpose is to determine the effect of quality indices of coal characterized by different degrees of metamorphism as well as petrographic and ultimate composition on the values of its grindability defined by the Protodyakonov and Hardgrove methods. Methods. 14 coal samples being a part of the raw material base of coking and chemical enterprises of Ukraine were studied. In terms of the samples, the parameters of technical, petrographic, and ultimate analysis were identified. GOST 21153.1-75 Rocks. Method of determining the Protodyakonov strength coefficient and ISO 5074:2015 Bituminous coal. Determination of Hardgrove grindability index were used to identify coal grindability. Graphical and mathematical dependencies between the indices of coal quality (R0, Vdaf, Cdaf, Oddaf) and values of its grindability (f and HGI) were developed. Findings. The obtained mathematical and graphic dependencies of the effect of different indices of coal quality (R0, Vdaf, Cdaf, Oddaf) on the values of its grindability (f and HGI) were obtained. It is shown that dependence of coal quality indices with its strength coefficient (f) is much lower (R2 = 0.550-0.716) than with the Hardgrove grindability index (HGI): R2 = 0.807-0.937. Originality. For the first time, comparative measurements of coal grindability according to the Protodyakonov and Hardgrove methods have been performed. It has been identified that the value of these indices are inversely proportional and described by a second-order polynom. Practical implications. The obtained graphical and mathematic dependencies can be used to predict the operation of crushing equipment for both individual coal and the one of different grade and ultimate composition at coking-chemical and heat-producing enterprises.Item Influence of Biocoke on Iron Ore Sintering Performance and Strength Properties of Sinter(Dnipro University of Technology, Dnipro, Ukraine, 2022) Kieush, Lina; Koveria, Andrii; Boyko, Maksym M.; Yaholnyk, Maksym V.; Hrubiak, Andrii; Molchanov, Lavr; Moklyak, VolodymyrENG: Purpose. The research purpose is to substantiate the use of biocoke as a fuel in the iron ore sintering, as well as its influence on the performance and properties of the resulting sinter. To completely replace conventional coke breeze, biocoke is produced using 5 wt.% biomass wood pellets at different carbonization temperatures of 950 or 1100°C. Further, the influence of biocoke on the sintering process and the sinter quality is studied at a high proportion of biomass pellets of 10, 15, 30, 45 wt.% and a carbonization temperature of 950°C. Methods. Carbonization is performed in shaft-type electric furnaces to produce laboratory coke or biocoke. Afterward, the sintering of iron ores is conducted on a sinter plant. To assess the sintering process and the quality of the resulting sinter, the filtration rate is determined on a laboratory sinter plant using a vane anemometer designed to measure the directional flow average velocity under industrial conditions. The sinter reducibility is studied using a vertical heating furnace to assess the effect of coke and biocoke on the sinter’s physical-chemical properties. Findings. It has been determined that biocoke, carbonized at a temperature of 950°C, has good prospects and potential for a shift to a sustainable process of iron ore sintering. Originality. It has been proven that biocoke with a biomass pellet ratio of up to 15 wt.%, obtained at a temperature of 950°C, does not affect the parameters characterizing the sintering process. The sinter strength indicators correspond to the use of 100 wt.% conventional coke breeze. Biocoke used with a high proportion of biomass pellets of 30 and 45 wt.% causes a deterioration in the sinter quality. Practical implications. The results of using biocoke with the addition of 5-15 wt.% biomass pellets and at a temperature of 950°C are within the standard deviation, which makes it possible to use biocoke with 15 wt.% biomass pellets instead of industrial coke breeze.Item Structurally Dependent Electrochemical Properties of Ultrafine Superparamagnetic ‘Core/Shell’ γ-Fe2O3/Defective α-Fe2O3 Composites in Hybrid Supercapacitors(MDPI, Switzerland, 2021) Bazaluk, Oleg; Hrubiak, Andrii; Moklyak, Volodymyr; Moklyak, Maria; Kieush, Lina; Rachiy, Bogdan; Gasyuk, Ivan; Yavorskyi, Yurii; Koveria, Andrii; Lozynskyi, Vasyl; Fedorov, SerhiiENG: The paper presents a method for obtaining electrochemically active ultrafine composites of iron oxides, superparamagnetic ‘core/shell’ γ-Fe2O3/defective α-Fe2O3, which involved modifying sol-gel citrate synthesis, hydrothermal treatment of the formed sol, and subsequent annealing of materials in the air. The synthesized materials’ phase composition, magnetic microstructure, and structural, morphological characteristics have been determined via X-ray analysis, Mossbauer spectroscopy, scanning electron microscopy (SEM), and adsorption porometry. The mechanisms of phase stability were analyzed, and the model was suggested as FeOOH – γ-Fe2O3 – α-Fe2O3. It was found that the presence of chelating agents in hydrothermal synthesis encapsulated the nucleus of the new phase in the reactor and interfered with the direct processes of recrystallization of the structure with the subsequent formation of the α-Fe2O3 crystalline phase. Additionally, the conductive properties of the synthesized materials were determined by impedance spectroscopy. The electrochemical activity of the synthesized materials was evaluated by the method of cyclic voltammetry using a three-electrode cell in a 3.5 M aqueous solution of KOH. For the ultrafine superparamagnetic ‘core/shell’ γ-Fe2O3/defective α-Fe2O composite with defective hematite structure and the presence of ultra-dispersed maghemite with particles in the superparamagnetic state was fixed increased electrochemical activity, and specific discharge capacity of the material is 177 F/g with a Coulomb efficiency of 85%. The prototypes of hybrid supercapacitor with work electrodes based on ultrafine composites superparamagnetic ‘core/shell’ γ-Fe2O3/defective α-Fe2O3 have a specific discharge capacity of 124 F/g with a Coulomb efficiency of 93% for current 10 mA.Item Metallurgical Coke Production with Biomass Additives: Study of Biocoke Properties for Blast Furnace and Submerged(MDPI, Switzerland, 2022) Bazaluk, Oleg; Kieush, Lina; Koveria, Andrii; Schenk, Johannes; Pfeiffer, Andreas; Zheng, Heng; Lozynskyi, VasylENG: Biocoke has the potential to reduce the fossil-based materials in metallurgical processes, along with mitigating anthropogenic CO2- and greenhouse gas (GHG) emissions. Reducing those emissions is possible by using bio-based carbon, which is CO2-neutral, as a partial replacement of fossil carbon. In this paper, the effect of adding 5, 10, 15, 30, and 45 wt.% biomass pellets on the reactivity, the physicomechanical, and electrical properties of biocoke was established to assess the possibility of using it as a fuel and reducing agent for a blast furnace (BF) or as a carbon source in a submerged arc furnace (SAF). Biocoke was obtained under laboratory conditions at final coking temperatures of 950 or 1100 °C. Research results indicate that for BF purposes, 5 wt.% biomass additives are the maximum as the reactivity increases and the strength after reaction with CO2 decreases. On the other hand, biocoke’s physicomechanical and electrical properties, obtained at a carbonization temperature of 950 °C, can be considered a promising option for the SAF.Item Structurally Dependent Electrochemical Properties of Ultrafine Superparamagnetic ‘Core/Shell’ γ-Fe2O3/Defective α-Fe2O3 Composites in Hybrid Supercapacitors(MDPI, Switzerland, 2021) Bazaluk, Oleg; Hrubiak, Andrii; Moklyak, Volodymyr; Moklyak, Maria; Kieush, Lina; Rachiy, Bogdan; Gasyuk, Ivan; Yavorskyi, Yurii; Koveria, Andrii; Lozynskyi, Vasyl; Fedorov, SerhiiENG: The paper presents a method for obtaining electrochemically active ultrafine composites of iron oxides, superparamagnetic ‘core/shell’ γ-Fe2O3/defective α-Fe2O3, which involved modifying sol-gel citrate synthesis, hydrothermal treatment of the formed sol, and subsequent annealing of materials in the air. The synthesized materials’ phase composition, magnetic microstructure, and structural, morphological characteristics have been determined via X-ray analysis, Mossbauer spectroscopy, scanning electron microscopy (SEM), and adsorption porometry. The mechanisms of phase stability were analyzed, and the model was suggested as FeOOH → γ-Fe2O3 → α-Fe2O3. It was found that the presence of chelating agents in hydrothermal synthesis encapsulated the nucleus of the new phase in the reactor and interfered with the direct processes of recrystallization of the structure with the subsequent formation of the α-Fe2O3 crystalline phase. Additionally, the conductive properties of the synthesized materials were determined by impedance spectroscopy. The electrochemical activity of the synthesized materials was evaluated by the method of cyclic voltammetry using a three-electrode cell in a 3.5 M aqueous solution of KOH. For the ultrafine superparamagnetic ‘core/shell’ γ-Fe2O3/defective α-Fe2O composite with defective hematite structure and the presence of ultra-dispersed maghemite with particles in the superparamagnetic state was fixed increased electrochemical activity, and specific discharge capacity of the material is 177 F/g with a Coulomb efficiency of 85%. The prototypes of hybrid supercapacitor with work electrodes based on ultrafine composites superparamagnetic ‘core/shell’ γ-Fe2O3/defective α-Fe2O3 have a specific discharge capacity of 124 F/g with a Coulomb efficiency of 93% for current 10 mA. View Full-Text.Item Modification of the Electrode Pitch Operational Properties(Lviv Polytechnic National University, Lviv, Ukraine, 2021) Starovoyt, Anatoly; Malyi, Evgeniy; Chemerinskii, Michael; Timoshenko, AnatolyENG: In this work, the influence of the carbon modifier type and its amount on the processes of carbonization of the electrode pitch and carbon masses for carbon production was investigated experimentally. The paper presents the processes that occur during the carbonization of the electrode pitch and the change in its properties during the modification process. It is shown that the most promising additive is a medium-boiling polymer mixture, which contributes to the carbonization of pitch and improves the physico-chemical properties.Item Production of Iron Ore Pellets by Utilization of Sunflower Husks(Technical University of Košice, Slovakia, 2021) Kieush, Lina; Boyko, Maksym; Koveria, Andrii; Yaholnyk, Maksym; Poliakova, NataliaENG: Steel production is the most dynamic industry and one of the key sectors for developing the global economy. The growing iron ore production increases its beneficiation and granulating for subsequent iron and steel production use. As a result, CO2 emissions and harmful substances increase, negatively affecting society and the environment. In this regard, it is important to study the use of biomass for the production of iron ore pellets. Lignocellulosic biomass is a renewable and sustainable source of heat and energy that can mitigate climate change. The influences of alternative fuel use on technological indicators of the process and quality of iron ore pellets have been analyzed. The efficiency of using 40.4-60.7 vol.% of sunflower husks on the combined machine “straight grate - rotary kiln - annular cooler” to partially replace natural gas in iron ore pellets production under industrial conditions has been studied. It was found that the combustion of sunflower husks generates enough heat (19.31 MJ kg−1) to obtain iron ore pellets with good strength. After evaluating the parameters of the combined machine and the quality of the resulting pellets, it was determined that it would be rational to replace up to 48.3 vol.% of natural gas with crushed sunflower husks.Item Nanostructured Mesoporous ℽ-Fe2O3: a Novel Photocatalyst for Degradation of Organic Pollutants(Vasyl Stefanyk Precarpathian National University, Ivano-Frankivsk, Ukraine, 2021) Hrubiak, A. B.; Khyzhun, O. Yu.; Ostafiychuk, B. K.; Moklyak, V, V.; Yavorskyi, Yu. V.; Lisovsky, R. P.; Keush, Lina G.; Onyskiv, B. B.ENG: The modified sol-gel synthesis technique was used to created of nanostructured maghemite (γ-Fe2O3). It has been shown that the molar concentration of the original precursors during synthesis affects on the average particle sizes, specific surface area, pore size distributions, optical and conductivity properties. The XPS metod allowed to establish features of electronic structure of the synthesized materials. Optimal conditions for the synthesis of nanostructured maghemite with mesoporous structure were selected. The mechanism of electrical conductivity formation for synthesized mesoporous materials was established. The width of the band gap is determined and its dependence on the molar concentration of precursors is established. The positive correlation between the specific surface area of γ-Fe2O3 samples and photocatalytic activity was installed - the photocatalytic activity of synthesized γ-Fe2O3 increase with growth of specific surface area of γ-Fe2O3 samples.