Electric arc furnace Research Papers (original) (raw)

In this paper is analyzing the current operating conditions of one electric arc furnace (EAF) in order to evaluate the best option to solve the energy consumption problem. Experimental results show that EAFs represent a substantial source of electric disturbances, such as voltage fluctuations, flicker, harmonics, and unbalance between phases. Improvement of the energetic performances of an EAF imposes a careful technical and economical analysis. The possible compensation solutions include passive filter, SVC (static var compensator) and STATCOM (static synchronous compensator).Finally, the guideline for compensator selection and performance estimation is obtained.

- by
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- Engineering, Harmonic Analysis, Flicker, Electric arc furnace

The present study aims to investigate the opportunity to largely substitute natural aggregates of traditional concrete with Black/Oxidizing Electric Arc Furnace (EAF) slag. Compressive and tensile strength, elastic modulus and durability characteristics (accelerated aging, freezing and thawing, wetting and drying) of concrete containing EAF slag as aggregate according to Fuller's ideal grading curve were experimentally investigated. This study aims to improve the scarce database of mechanical and durability tests on this type of concrete and give some insights to improve durability properties of concrete made with EAF slag, not only using modern agents and additives, but also working on the actual grading curve of aggregates used, closely connected to the overall durability for any kind of concrete. Concrete made with EAF slag as aggregate showed good strength characteristics since, in normal environmental conditions, strength properties of the conglomerate containing EAF slag are totally comparable (or even better) than those observed for traditional concrete. Conversely, the typical chemical and physical properties of EAF slag, such as the high content in calcium and magnesium oxides inclined to hydration, may be a limit for the durability of the resulting concrete: on one hand the durability can be strongly improved even in critical freezing/thawing environmental conditions by a small amount of air-entraining agent, on the other hand, this conglomerate still remains rather vulnerable to repeated cycles of wetting and drying.

- by Stelios Antiohos and +1
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- Civil Engineering, Building, Durability, Electric arc furnace

The main frequency is an important parameter of an electrical power system. The frequency can change over a small range due to generation-load mismatches. Some power system protection and control applications, e.g., frequency relay for load shedding, load-frequency controller, require accurate and fast estimation of the frequency. Most digital algorithms for measuring frequency have acceptable accuracy if voltage waveforms are not distorted. However, due to nonlinear devices, e.g., semiconductor rectifiers, electric arc furnaces, the voltage waveforms can include higher harmonics. The paper presents a new method of measurement of power system frequency, based on digital filtering and Prony's estimation method. Simulation results confirm, that the proposed method is more accurate than others, e.g., than the method based on the measurement of angular velocity of the rotating voltage phasor.

- by T. Lobos
- •
- Power Systems, Power System, Control Systems, Power System Protection

The computer simulation that is presented here is the response of an industrial challenge about how the electric arc furnace, where the smelting process of magnesium oxide (MgO) is taking place, should be charged for avoiding shell overheating. If solid MgO is charged at a very high rate, the processing time becomes very long; on the other hand, if the feed rate is too slow, external shell made of steel reaches temperatures above its melting point.

- by Carlos Esparza
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- Materials Engineering, Computer Simulation, Electric arc furnace, Thermal Analysis

Energy consumption and production capacity are two major concerns in the steel making industries which are using electric arc furnace (EAF). To improve the performance of EAF, a new initiative technique has been introduced in which sponge iron particles are preheated before entering the furnace. A heat exchanger is used to transfer waste energy from EAF flue gas to a neutral gas like nitrogen, which in turn preheats the sponge iron particles in the fixed bed. The method has several desirable advantages including electric energy saving, increasing the productivity and reduction in electrode and refractory consumption. In order to estimate the extent of energy saving and productivity increase, the preheating process was simulated in the bed. The thermal characteristics of the fixed bed were predicted by a numerical solution of differential equations for granular sponge iron and heating gas. The temperature of sponge iron particles and heating gas were also predicted in different layers of the bed and at different times. Based on the simulation results it is found that the energy consumption in the EAF can be reduced up to 14% and productivity can be increased up to 13%.

Stable smelter operation is critical for successful production of base metals from particulate ore. This work studies the operation of an industrial direct current electric arc furnace that operates as a smelter
in a large-scale metallurgical process. Specifically, unexpected loss of the plasma arc is an important unresolved problem with a significant impact on the production efficiency of the process. Moreover, given that electric arc furnaces are highly energy intensive units, even minimal improvements to the overall production efficiency represent meaningful reductions in the environmental footprint of the process over the lifetime of operation. A predictive inferential sensor is proposed to avoid high risk operating regimes and reduce the overall environmental footprint of the process. The alarm identifies high risk situations and instructs operators to take corrective actions to avoid the loss of arc. Large amounts of historical industrial process data have been collected, pre-processed and leveraged in a cross-validated supervised learning framework that trains the inferential sensor model. New data, previously unseen by the model, are drawn from the historical database and used to test the ability of the model to generalize. This work showcases our progress to date including the training, validation and testing of competing inferential sensor models and their ability to predict arc loss on industrial data.

- by Lee Rippon
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- Metallurgical Engineering, Chemical Engineering, Machine Learning, Fault Detection

As a result of optimisation of high current circuit for the furnace 7.75 MVA, its substitute values of phase reactances have been considerably decreased and its asymmetry has been minimised. Decrease in the voltage drop of the high current circuit influenced advantageously a change in furnace electrical parameters and forced increase in its electric resistance. It influenced positively increase in power factor cos φ and increased the furnace active power. In spite of an improvement in properties of the high current circuit, in the early stage after furnace modernisation, a deterioration of technical and economic indices of ferrosilicon FeSi75 melting process was experienced and an expected improvement in energy consumption rate was not achieved. It was found that it was connected with the influence of the change in electric parameters of the high current circuit on decrease in the depth of immersion of electrodes which influenced negatively temperature conditions of the process.

- by Arif Ertaş
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- Engineering, Harmonic Analysis, Iron, Electric arc furnace

Electric arc furnace dust (EAFD) is a hazardous industrial waste generated in the collection of particulate material during steelmaking process via electric arc furnace. Important elements to the industry such as, Fe and Zn are the main ones in EAFD. Due to their presence, it becomes very important to know how these elements are combined before studying new technologies for its processing. The aim of this work was to carry out a chemical, physical, structural and morphological characterization of the EAFD. The investigation was carried out by using granulometry analysis, chemical analysis, scanning electron microscopy (SEM), energy dispersive spectroscopy via SEM (EDS), X-ray mapping analysis via SEM, X-ray diffraction (XRD) and Mössbauer spectroscopy. By XRD the following phases were detected: ZnFe 2 O 4 , Fe 3 O 4 , MgFe 2 O 4 , FeCr 2 O 4 , Ca 0.15 Fe 2.85 O 4 , MgO, Mn 3 O 4 , SiO 2 and ZnO. On the other hand, the phases detected by Mössbauer spectroscopy were: ZnFe 2 O 4 , Fe 3 O 4 , Ca 0.15 Fe 2.85 O 4 and FeCr 2 O 4 . Magnesium ferrite (MgFe 2 O 4 ), observed in the XRD pattern as overlapped peaks, was not identified in the Mössbauer spectroscopy analysis.

- by F. Brehm and +1
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- Engineering, Metallurgy, Mössbauer Spectroscopy, Brazil

The Voltage flicker, a phenomenon of annoying light intensity fluctuation, caused by rapid change in industrial and domestic load such as Electric Arc Furnaces (EAF), rolling mills, welding equipments and pumps operating periodically has been a major concern for supply utilities, electricity regulatory agencies and customers. Static Voltage Compensators (SVC's) and Static Synchronous Compensators (STATCOM) have been able to solve the voltage flicker problem by rapidly controlling the reactive power. But, the control of active power along with reactive power control helps to mitigate the voltage flicker problem more effectively. In this paper, voltage flicker mitigation of EAF with STATCOM along with Battery Energy Storage System (BESS) is presented and performance results of the system using PSCAD/EMTDC software are analyzed.

- by Vasudeo Virulkar
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- Power Quality, Reactive Power, Electric arc furnace, Energy Storage

Based on the electrical parameters of a 20 MVA ferrosilicon furnace, a methodology of identification of characteristic ferrosilicon smelting states described as carbon excess and carbon deficiency in the reaction zones ('over-coked', 'under-coked') has been presented. Relations between the electrical parameters and assessments made by furnace operators regarding characteristic furnace states related to amounts of carbon in the reaction zones have been demonstrated. The results show that the reactive power measurements as well as the k, c3 (Andreae’s, Westly’s) parameters, provide the same information on the furnace state and have a close relation with resistivity of the current-conducting zones. Similar information on the level of carbon balance in the reaction zones is obtained from the harmonic analysis of phase voltages and currents or measurements of higher harmonic components using high-pass filters.

- by Bolesław Machulec
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- Electric arc furnace, Ferroalloys, Ferrosilicon

Recycling end of life products, such as waste tires and waste plastics in iron-and steelmaking permits their use as energy and material resources. The current paper discusses the combustion efficiencies of blends of metallurgical coke (MC) with plastics for electric arc furnace (EAF) steelmaking. Laboratory tests involved the combustion in a drop tube furnace (DTF) at 1473 K of MC premixed with different proportions of plastics, polypropylene (PP), and high-density polyethylene (HDPE) (10-30%) under a 20% O 2 and 80% N 2 gas mixture. In the tested conditions, coke-plastic blends indicated higher combustion efficiencies compared to coke. The gas-phase reactions appear to be influenced by the amount of volatile matter present in the carbonaceous matrix and its subsequent effect on the structural transformation of the particles because of the release of volatiles. The surface area of the coke-polymeric mixtures before and after combustion was found to be higher than the surface area of coke alone. The residual chars collected after the reaction in the DTF were characterized as a function of pore volumes and surface area of the particles. A previous study has demonstrated the possibility of partially replacing conventional coke in EAF steelmaking with end of life rubber tires. The present paper studies the potential replacement of MC with waste materials, such as PP and HDPE, as auxiliary fuels in EAF steelmaking. A comparison to previously reported combustion efficiencies for rubber blends is also provided.

- by Rita Khanna
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- Engineering, Energy, Structural Transformation, Electric arc furnace

Supersonic coherent gas jets are now used widely in electric arc furnace steelmaking and many other industrial applications to increase the gas-liquid mixing, reaction rates, and energy efficiency of the process. However, there has been limited research on the basic physics of supersonic coherent jets. In the present study, computational fluid dynamics (CFD) simulation of the supersonic jet with and without a shrouding flame at room ambient temperature was carried out and validated against experimental data. The numerical results show that the potential core length of the supersonic oxygen and nitrogen jet with shrouding flame is more than four times and three times longer, respectively, than that without flame shrouding, which is in good agreement with the experimental data. The spreading rate of the supersonic jet decreased dramatically with the use of the shrouding flame compared with a conventional supersonic jet. The present CFD model was used to investigate the characteristics of the supersonic coherent oxygen jet at steelmaking conditions of around 1700 K (1427°C). The potential core length of the supersonic coherent oxygen jet at steelmaking conditions was 1.4 times longer than that at room ambient temperature.

Electric arc furnaces (EAF) have the capabilities required for furnaces used for metallurgical research. An electric arc furnace was designed and constructed to melt approximately 5kg of steel/cast iron scraps, using locally produced Soderberg electrodes. Tests carried out showed that it required about 60 minutes to heat up the furnace to the melting temperature of cast iron (1150C -1400C). It took about 95 minutes to melt the first charge of 2kg resulting in a melting rate of 21.05g/minute. The average electrode consumption rate was 0.0467cm/minute. A transformer efficiency of about 83% was also achieved.

- by DAVID OLAWALE
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- Iron, Cast Iron, Electric arc furnace

En su más de un siglo de existencia, los hornos eléctricos de arco han evolucionado radicalmente, tanto en los aspectos tecnológicos como en la función que cumplen y los tipos de acero que producen. Desarrollados para producir aceros especiales, con requerimientos de altas temperaturas para la fusión de ferroaleaciones, penetraron luego en la década del ’60 en las miniacerías, acompañando a las máquinas de colada continua de palanquillas, para la producción de barras de refuerzo de hormigón y alambrones de aceros al carbono. En las décadas del ‘80 y el ’90 se produce un nuevo salto, acompañando la introducción de las máquinas de colada continua de planchones delgados, para la fabricación de productos planos de aceros al carbono
y de alta aleación. Paralelamente a la ampliación de su campo de aplicación, se los fue dotando de tecnologías que permitieron acercar
sus tiempos de proceso a los de las acerías al oxígeno. La escoria espumosa y los paneles refrigerados hicieron posible el uso de ultra alta potencia. Se incorporó la energía química, inicialmente mediante lanzas y actualmente mediante inyectores. Los métodos de control se fueron
haciendo cada vez más sofisticados. Con la incorporación de la metalurgia de cuchara, la función del horno se centró en la fusión de la carga, siendo el eje de la productividad de las acerías. Actualmente
los hornos eléctricos de arco son poderosas máquinas de reciclar acero, que hacen la tercera parte de la producción mundial, con una menor emisión de gases de efecto invernadero con respecto a la ruta basada en altos hornos y acería al oxígeno. Pero es inherente al proceso una significativa pérdida de energía, principalmente a través de los gases de escape. En la Figura 1 se presenta un balance de energía típico de un horno eléctrico moderno [1]. Se observa que cerca de un tercio de la
energía ingresada se pierde en los gases de escape, en forma de calor sensible y energía química. Una distribución similar ocurre en las acerías al oxígeno. En este campo, el tema está más avanzado y hay una cantidad importante de acerías, sobre todo en Europa y Japón, que recuperan el calor de los gases para generar vapor. En la actualidad, el esfuerzo en los hornos eléctricos, desde el punto de vista energético, se centra en disminuir el consumo total de energía más que en recuperar la energía perdida. Es mejor usar 1 kWh menos que recuperar 1 kWh [2]. Sin embargo, esto tiene un límite. En la medida que los hornos se modernizan, se acercan a ese límite. Esto hace que se empiece a poner la mirada en la posibilidad de recuperar la energía. Este problema no es sencillo de resolver, dado que la liberación de calor a los gases de escape es muy variable a lo largo de la colada (Figura 2). Se ha introducido la recuperación del calor de los gases para el precalentamiento de la chatarra en los procesos con carga continua (Consteel) y en los procesos con cubas por sobre la bóveda (finger
shaft furnace) [1]. Se están proponiendo soluciones para la recuperación de la energía de los gases en la generación de vapor, mediante diversos esquemas que comienzan a aplicarse industrialmente en hornos eléctricos. En este trabajo se detallan los diversos esquemas propuestos para resolver el problema.

- by Jorge Madias
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- Steel Making, Energy Recovery Systems, Steel, Electric arc furnace

Los electrodos de grafito artificial son un estándar en la producción de acero en hornos eléctricos. El grafito artificial posee una alta conductividad eléctrica y elevada resistencia al choque térmico que lo hacen imprescindible para este uso. El consumo medio ha sido cuantificado, para un gran número de acerías eléctricas del grupo ArcelorMittal, en 1,43 kg/t [1]. La producción de acero crudo en acerías eléctricas fue en el año 2010 de 406 Mt. Podría estimarse el consumo de electrodos para hornos eléctricos en el orden de las 600.000 t/año; a esto se le debería sumar el consumo en los hornos cuchara. Entre los principales fabricantes están GrafTech International, SGL Group, Showa Denko Carbon, Tokai Carbon, HEG Ltd., Superior Graphite, UK CG, Beijing Fangda Carbon Tech, Chengdu Ronguang Carbon, Fangda Carbon New
Material, Fushun Carbon, Guangshan Shida Carbon, Hefei Carbon, GES (China), Jilin Carbon Import & Export. Es un mercado competitivo en costos, calidad y servicio, con estrategias diferenciadas y en el que ha habido en la última década un proceso importante de fusiones y adquisiciones. Una parte de las empresas mencionadas tiene sitios de producción en varios países. Se trata de una industria madura, que utiliza en general sistemas de producción modernos, con importante
grado de automatización, capaces de
formular electrodos con un alto grado de
repetitividad.
En el Cuadro 1 se presentan algunas fechas
importantes en el desarrollo y aplicación
de los electrodos de grafito [2].
Las materias primas para la producción
de los electrodos son el coque de petróleo,
preferentemente del tipo denominado
aguja y la brea de alquitrán de hulla.
Estos materiales se mezclan y procesan
a alta temperatura en varios pasos, hasta
obtener el grafito sintético. Es un producto
con un alto valor agregado energético.
En los párrafos siguientes se presentan
detalles sobre las materias primas utilizadas,
el proceso de fabricación, el diseño
de los electrodos y su aplicación, desde
el punto de vista de algunas de las novedades
tecnológicas que se han introducido
en las últimas décadas.
Cabe mencionar que los avances en las
materias primas, el proceso de fabricación
y la performance en uso son lentos.
El proceso de producción de los electrodos
es largo, de hasta dos meses; a esto
debe sumarse el tiempo de prueba en la
acería para saber si una cierta formulación
presenta ventajas, donde un gran
número de variables puede influir sobre
los resultados [4].

- by Jorge Madias
- •
- Steel Making, Graphite, Steel, Ironmaking and Steelmaking

There is an important variation in scrap quality and alternative iron sources depending on country and region. Besides, a variery of furnace designs are available. This paper intends to look at the influence of metallics type and EAF design on specific consumption of energy, oxygen and other inputs, as well as on some productivity indicators, based on a survey of published figures of EAFs around the world. The results obtained are analyzed in detail. The data base was selected from publications in technical journals and presentations in conferences, since 2010 to February 2017. All furnaces included are intended for production of rolled products: EAFs for steel castings, forgings and powder are not included, as well as furnaces producing exclusively stainless and tool steels. Also excluded are furnaces with heat capacity lower than 30 t.
The universe surveyed includes 190 furnacess. Twin shell furnaces are contabilized as one furnace (including the CONARC furnaces). All steelmaking regions are included (figure 1). Charge types include from 100% scrap to 40% pig iron, 60% hot metal, 100% DRI/HBI and 100% hot DRI. Products include merchant long products, SBQ, flat products (coil and plate) and seamless pipes.

- by Jorge Madias and +1
- •
- Energy, Metallurgy, Benchmarking, Steel Making

The popularity of Organic Rankine Cycle technology in waste heat recovery applications has experienced a fast growth in the last decade. One of the main fields of application is the Iron&Steel industry, and in particular waste heat recovery from Electric Arc Furnace. The very characteristics of the exhaust heat (non-continuous availability, thermal power fluctuations and amount of power) makes ORC the most suitable technology to produce electric power from the EAF sources. The experience of a Turboden ORC plant installed at Feralpi-Riesa steel plant in Germany-first EAF waste recovery system based on ORC-will be presented. To conclude the paper, achievement of Riesa plant and new investments on waste heat recovery plants from EAF around the world will be exposed.

- by Filippo Vescovo
- •
- Energy efficiency, Steel Making, Electric arc furnace, Organic rankine cycle

After almost half a century of experience in using DRI/HBI in electric arc furnaces (EAFs), and taking into account the decrease of natural gas cost in the USA, it is interesting to revisit some trends and controversial issues around this alternative iron source. This paper reviews aspects like the evolution of iron ore quality and its influence on EAF operation; DRI stockpiling and transport, regarding the risk for self-combustion; optimum charge design; cold DRI/HBI charging (fifth hole, bucket, transporter); hot charging (ways and results); carbon content, metallization and silica in DRI/HBI, and its influence on EAF operation and performance; oxygen / carbon balance; chemical energy and DRI/HBI charge.

- by Jorge Madias and +1
- •
- Metallurgy, Steel Making, Steel, Electric arc furnace

La industria del acero latinoamericana continúa su esfuerzo de
modernización de sus instalaciones, incluso en el complicado
marco de la situación mundial generada por la sobrecapacidad de
China y los subsidios del gobierno de ese país a las exportaciones
de acero. Una parte del esfuerzo de modernización se refleja en la construcción de plantas nuevas, que responden a diversas
necesidades. La industria siderúrgica latinoamericana continúa avanzando a pesar de la difícil situación que atraviesa con la crisis mundial de sobrecapacidad de acero, y las agresivas y subsidiadas exportaciones chinas. En los últimos cinco años se han incorporado nuevas plantas y otras están cerca de incorporarse. En el CUADRO 1 se presenta un listado de las mismas con sus principales características, y en la FIGURA 1 su localización. Se han incluido además de las plantas nuevas, instalaciones incorporadas en plantas existentes, siempre que significaran la introducción de una ruta de procesos nueva (por ejemplo, una acería eléctrica en una planta integrada basada en alto horno) y/o de una línea de productos diferentes (productos planos en una planta de largos o la inversa). No se incluyen inversiones en plantas existentes que no tuvieran esas características; tampoco proyectos cuya construcción no estén en una etapa avanzada. No se puede dejar de mencionar que en paralelo con este proceso, hubo diversos cierres totales y parciales de plantas. Muchos de los proyectos concretados en 2013-2017 fueron formulados en la etapa de crecimiento previa a la crisis de 2009, congelados durante ese momento y concretados cuando comenzó la recuperación. En cambio, los cierres de plantas corresponden especialmente a las especificidades de la crisis que afecta a Brasil. Algunos de estos cierres podrían ser transitorios. Para cada planta, se desarrollan los aspectos principales: el equipamiento y sus características, los productos y algunos aspectos técnicos que han sido presentados en publicaciones o congresos.

- by Jorge Madias
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- Steel Making, Steel, Blast Furnace, Ironmaking and Steelmaking

In this chapter, electric steelmaking is introduced with a short review: share, raw materials, operation, typical equipment, off-gas treatment, emissions. Electric-based steelmaking enjoys a much comfortable position than integrated classical blast furnace – oxygen steelmaking facilities, regarding greenhouse emissions. This is compared both for regions and for the world. For instance, the mostly EAF-based NAFTA countries, is nowadays the region where the production of steel generates lower specific emissions. This said (and detailed), the chapter continues with a discussion of the CO 2 emissions of the electric arc furnaces. A reference is be made to the use of alternative raw materials, as DRI/HBI, pig iron and hot metal. In relation with the EAF design, factors to be analyzed are the effects of different furnace designs on emissions: conventional, twin shell, conveyor scrap preheating and shaft scrap preheating are considered. The use of chemical energy is reviewed, as well as the effect of an external factor: how electric energy is generated .

- by Jorge Madias
- •
- Metallurgy, Steel Making, Steel, CO2 emissions

This paper reviews aspects of DRI/HBI use and production,
like the evolution of iron ore quality and its influence on EAF
operation; DRI stockpiling and transport, regarding the risk
for self-combustion; optimum charge design; cold DRI/HBI
charging (fifth hole, bucket, transporter); hot charging (ways
and results); carbon content, metallization and silica in DRI/
HBI, and its influence on EAF operation and performance;
oxygen/carbon balance; chemical energy and DRI/HBI charge.

- by Sara Hornby and +1
- •
- Electric arc furnace

Studies of the electrical, thermal, and mechanical stresses on power cables have received much attention in recent years. However, there is a research gap in studying the electromagnetic forces of the power cables of electric arc furnaces (EAFs). The challenges of studying the EAF's power cable are highlighted because of the special cyclic operations, inrush currents, current harmonics, and short circuit faults of the EAF. The electromagnetic forces are influenced by the magnitude current and behavior of the current passing through the cable. The main purpose of this paper is to respond to a research gap about studying the electromagnetic forces of EAF's power cables under different normal and abnormal conditions. The proposed study is implemented in the COMSOL Multiphysics environment. Test results of applying the proposed method to an actual test system highlight the advantages of the proposed study. Simulation results imply that current harmonics, particularly the 7th harmonic order, intensify the electromagnetic forces. Test results emphasize the impacts of short circuit currents on the induced electromagnetic force. Furthermore, test results show that although cable clips limit the cable movement, internal von Mises cable stress increase due to the deployment of cable clips.

- by Hamed Hashemi-dezaki and +1
- •
- Electrical Engineering, Finite element method, Electromechanical Engineering, Comsol Multiphysics Simulation

In the electric arc furnace (EAF) steel production processes, scrap steel is principally used as a raw material instead of iron ore. In the steelmaking process with EAF, scrap is first melted in the furnace and then the desired chemical composition of the steel can be obtained in a special furnace such as ladle furnace (LF). This kind of furnace process is used for the secondary refining of alloy steel. L F furnace offers strong heating fluxes and enables precise temperature control, thereby allowing for the addition of desired amounts of various alloying elements. It also provides outstanding desulfurization at high-temperature treatment by reducing molten steel fluxes and removing deoxidation products. Elemental analysis with mass balance modeling is important to know the precise amount of required alloys for the L F input with respect to scrap composition. In present study, chemical reactions with mass conservation law in EAF and L F were modeled altogether as a whole system and chemical compositions of the final steel alloy output can be obtained precisely according to different scrap compositions, alloying elements ratios, and other input amounts. Besides, it was found that the mass efficiency for iron element in the system is 95. 93%. These efficiencies are calculated for all input elements as 8. 45% for C , 30. 31% for Si, 46. 36% for Mn, 30. 64% for P, 41. 96% for S , and 69. 79% for Cr, etc. These efficiencies provide valuable ideas about the amount of the input materials that are vanished or combusted for 100 kg of each of the input materials in the E A F and L F system.

- by İsmail Ekmekçi
- •
- Materials Engineering, Raw materials, Iron, High Temperature

The characterization and the agitation leaching of electric arc furnace dust (EAFD) by diluted sulphuric acid have been studied in Part I, as a separate article. The aim of the present research work (Part II) is the development of a purification process of the leach liquor for the recovery of high-purity zinc by electrowinning. The proposed hydrometallurgical process consists of the following four (4) unit operations:

- by Petros Tsakiridis
- •
- Engineering, Electrochemistry, Metallurgy, Scanning Electron Microscopy

In this study, energy and conservation analyses are applied to the production of steel process in the electric arc furnace. The scrap pre-heating system, stack gas and cooling water leaving the furnace are investigated, and the obtained... more

h i g h l i g h t s The workability of the concrete reduces as the EAFS replacement level increases. The use of EAFS reduced the setting time of GGBS-PFA ternary blended concrete. Incorporation of EAFS tends to enhance the mechanical strength of concrete. Incorporation of EAFS reduced the magnitude of drying shrinkage of concrete. EAFS can be partial or fully utilize in the production of concrete. a b s t r a c t The manufacturing of concrete composites have released high volume of carbon dioxide (CO 2) gaseous to the environment in the world. Therefore, finding an alternative materials to replace the raw material used in the production of concrete composites have become a current agenda. The industrial waste materials mainly from local coal-fuelled power plant, granite quarrying process, and iron and steel manufacturing industry were utilized in the high-performance concrete production. The waste materials incorporated included ground granulated blast-furnace slag (GGBS), pulverized fly ash (PFA), granite quarry dust (GQD) and electric arc furnace slag (EAFS) were used to partially or completely replace the usage of a synthetic and natural constituent materials in the concrete production which included ordinary Portland cement (OPC), natural river sand (NRS), and natural granite rock (NGR). The study was aimed to establish the feasibility of using EAFS as partial or complete replacement of NGR as the coarse aggregate of concrete with other industrial waste materials in the binder and fine aggregate phase. In addition, the method of optimization on the OPC-GGBS-PFA as a ternary blended binder system was also established. Meanwhile, the optimum combination of chemical admixture dosage was also determined in this study. The concrete composition with the established optimum ternary blended binder system, chemical admixture combination and NRS-GQD composition as a fine aggregate were examined with various NGR replacement level with EAFS ranging from 0% to 100% at the increment of 20%. The properties of the concrete mixes were examined by setting time test on the fresh concrete, mechanical strength tests and drying shrinkage assessment on the hardened concrete. The results showed that the inclusion of the aforementioned waste tends to improve the mechanical strength properties of the concrete, while, reducing the magnitude of length change in terms of drying shrinkage. With such, a concrete with compressive strength of 80 MPa able to be produced with the used of waste material from the industry up to 80% of the total volume.

Quienes estuvieron siempre conmigo, dándome los recursos y las herramientas necesarias para cumplir esta meta que distaba mucho a realizarse. Ustedes me brindaron y me ofrecieron el apoyo necesario para verla realizada aun cuando yo ya... more

- by Alberto Mora
- •
- Engineering, Metallurgy, Mössbauer Spectroscopy, Brazil

Electric arc.f'urmwe control may be improved considerably using a dmtl impedance/ current control strategy, a derivative regulator, a temperature weighting adaptive controller and estimates of the molten steel temperature and carbon... more

- by Frank Boland
- •
- Engineering, Mathematical Sciences, Automatica, Electric arc furnace

A critical review was conducted on existing literature concerning life cycle assessment (LCA) and its application to the minerals and metals sector. This extensive literature search uncovers many of the issues that require immediate attention from the scientifi c community involved with LCA. The methodological drawbacks, mainly problems with inconsistencies in LCA results for the same situation under different assumptions and issues related to data quality, are considered to be the current shortcomings of LCA. In the minerals and metals sector, it is important to increase the objectivity of LCA by way of estimating and reporting those uncertainties; for example, whether land use has to be considered in detail or at a rough level. In regard to abiotic resource characterisation, the weight and time scales to be considered become a very critical issue of judgement. How the temporal and spatial dimensions should be incorporated into LCA is one of the biggest challenges ahead for those who are concerned. Addressing these issues will enable LCA to be used as a policy tool in environmental decision making. There has been enormous unresolved debate with respect to land use impacts, abiotic resource depletion, allocation procedure openloop recycling and spatial and temporal dimensions. An example case has been presented for Australian iron ore using SimaPro software based on

During the years 2001 -2002, a comprehensive study regarding of the CO 2 emission related to the steel production for the integrated steel making production route was carried out. The study was financed by SSAB and carried out by a research group with members from SSAB, MEFOS and LTU. The aim was to study the emissions from the existing system and how these could be influenced by process changes and by process modifications. The calculations were made using a global spreadsheet model for calculating the CO 2 emissions, developed from an existing Energy-and Process Integration model of the same system. The calculated cases included the existing BF/BOF route as well as integration of other processes e.g. an electric arc furnace, COREX, DR processes and new future smelting reduction process (Sidcomet). All new existing alternative ore based process technologies would increase the specific CO 2 emission from the system. A technology transfer to scrap based metallurgy would significantly decrease the emission level, but is not feasible for SSAB due to the future product mix and the structure of scrap availability. In a 5-20 year perspective the existing steel making process route with the use of magnetite ore for pellet production has the lowest specific CO 2 emission. In a long-term perspective (20 -50 years) alternative process routes, e.g., based on H 2 and DRI could be of interest. Studies on such changes are, however, big projects and should be carried out as joint European and/or international efforts.

- by Carl-erik Grip
- •
- Mechanical Engineering, Technology transfer, Green Energy, Process Integration

- by David Olawale PhD, PMP
- •
- Iron, Cast Iron, Electric arc furnace

Metallurgical and Mining Industry. A method for simultaneous solution of equations of material balance of the process and mathematical description of the equilibrium with the definition of active ingredients of slag as the phase with itinerant electrons is developed. To find solutions in the method of iterations there tested steepest descent algorithms and random search steps. The proposed approach provides a preliminary assessment of the results of the process steps with the process model, which will allow the staff of electric arc furnace to make right decisions. The use of modern computer technology to support management decision-making process eliminates the computational constraints and performs the 9 Metallurgical and Mining Industry No.6 — 2016 Automatization calculation of process parameters with the help of developed model.

- by Viktor Gogunsky and +2
- •
- Modeling and Simulation, Electric arc furnace

This paper introduces a new method for calculating the voltage flicker characteristics. A voltage waveform envelope, which captures the main flicker characteristics, is obtained by calculating rms values instantaneously using a moving window approach. The S-transform (ST) is then used to extract the voltage flicker components for each frequency. The multiresolution characteristic of the ST provides timing data which presents a “Magnitude-Time” and “Frequency-Time” contour for tracking flicker. The effects of signal sampling rate, voltage harmonics, and frequency variation on the calculation results are considered. The results show that the proposed method can identify the frequency and magnitude of flicker components in a short time and with very good precision. This method is independent of calculating the fundamental frequency of the system, which has been used for flicker index calculation. Finally, the method is tested on a real voltage flicker signal sampled from the voltage signal of an electric arc furnace. The results are quite promising.

- by Navid Eghtedarpour
- •
- Harmonic Analysis, Power Quality, Fundamental Frequency, Wavelet Transform

The blast furnace process is still the predominant method for primary iron production. However, the disadvantages inherent to the process led to the development of alternative processes such as the mini blast furnace process, smelting reduction process, and direct reduction process. Many of these alternative processes are still under development. However, direct reduction processes have reached some level of commercial applicability and are considered to be the most developed alternative ironmaking route. It is coke-less and environmentally friendlier when compared to the blast furnace process. In addition, direct reduced iron has a well-defined chemical composition when compared with steel scrap and has efficient melting properties in the electric arc furnace. Consequently, there is a great increase in the demand for direct reduced iron in electric arc steel making. These attractive features have led to an increase in worldwide production of direct reduced iron, which is currently approaching 50 million tons. Thus, direct reduced iron is gaining more importance. Hence, this article summarizes the basic properties and features of direct reduced iron.

- by S. Komar Kawatra
- •
- Natural Gas, Iron, Electric arc furnace, Chemical Composition

Aluminium is extracted from the chief ore bauxite because of its abundance in nature, but the gas emissions produced by the process has made researchers and industrialists to look for alternatives. Since then the aluminium has been reprocessed and have been accessible in the secondary form with similar characteristics from its antecedent. A lot of recycling methods have been followed, this research work would give a detailed account of the properties of ADC – 12 aluminium ingots from different types of furnaces like Electric furnace, Oil furnace, Gas Furnace and Pit furnace, and compare the ADC – 12 aluminium ingot’s composition. The recycling efficiency of the furnaces, and Its costs were analysed and compared to each other to determine the best furnace that is appropriate for startup industries.

- by IAEME Publication
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- Recycling, Cost-Benefit Analysis, Energy efficiency, Electric arc furnace

There is an important variation in scrap quality and alternative iron sources depending on country and region. esides, a variety of furnace designs are available. This paper looks at the innuence of metallics type and AA design on specific consumption of energy, ooygen and other inputs, as well as on some productivity indicators, based on a survey of published figures of AAs around the world. The results obtained are analysed in detail.

- by Jorge Madias and +1
- •
- Energy Consumption, Steel Making, Steel, Scrap Metal

In the recycling industry, the recuperation of zinc from electric arc furnace dust by the Waelz process generates important quantities of slag. This slag presents good mechanical properties, and for the most siliceous slag, a high stability that would enable its use by total or partial substitution of certain granulates in civil engineering. Our study (within the framework of a European program, co-funded by the European Commission Ð DGXII) concerns the physico-chemical and mineralogical characterization and leaching behaviour of several types of Waelz slag. The leaching tests used are regulatory tests and speci®c characterization tests of leaching behaviour. They take into account the in¯uence of several main parameters of the valorization scenarios envisaged for the slag (e.g. pH, Redox potential, chemical nature of the leachant, type of contact Ð liquid/solid etc). The in¯uence of the chemical nature of the alkaline leachant (lime or NaOH) is particularly important in the case of release of lead (strongly leached by a lime solution), of zinc and of arsenic. The agreement between ANC test results and controlled pH test results can be noted. Leachability is largely controlled by pH in solution. Alkaline slags are more sensitive to the in¯uence of pH. The low buer capacity of the silica-rich slags implies that application or disposal of untreated slag in acid environments (pH 4±6) should avoided. To optimize integration of slags in materials, it will be necessary to orient research towards less alkaline binders than classical OP cements. A concrete with low limestone content where the alkalinity in the porewater would have a less corrosive eect on the vitreous phases of slags would seem more appropriate. #

- by Radu Barna
- •
- Environmental Engineering, Arsenic, Waste Management, European Commission

In this paper, the effects of transformer replacement on the electric arc furnace power system of an iron and steel plant have been investigated. The new operating strategy has been determined according to stable arc and maximum productivity requirements. Based on these new operating conditions, the sufficiency of the existing flicker compensation system in terms of the load balancing, power-factor correction, and flicker have been examined. All investigations made in this work are supported by real-time measurements.

- by Mehmet Ermis
- •
- Engineering, Power System, Energy Conservation, Operations Strategy

Plastics are potentially suitable for the removal of vapour phase PCDD/Fs in emissions from the electric arc furnace (EAF) steelmaking process. Three different commercial plastics, i.e. polypropylene BE170MO (Borealis A/S, Denmark), polypropylene in the form of 5 mm spheres (The Precision Plastic Ball Co. Ltd., UK) and polyethylene LD605BA (ExxonMobil Chemical, Belgium), have been studied using a novel experimental apparatus for the removal of vapour phase PCDD/Fs. Polypropylene BE170MO was identified to be the most suitable product amongst the three plastics in terms of PCDD/F sorption and potential industrial application. The optimum temperature for PCDD/F sorption on polypropylene BE170MO was below 90°C for a removal efficiency of >99% at an average vapour phase PCDD/F concentration of 3.5 ng I-TEQ/ Nm 3 . At 130°C, 53% of the PCDD/Fs trapped on polypropylene BE170MO were desorbed.

- by Bruce Ewan
- •
- Multidisciplinary, Adsorption, Electricity, Steel

The paper discusses the evolution of electric steelmaking technology in South America, Central America and Caribbean countries, on the basis of raw material utilization, electric energy and alternative energy use, start-ups, retrofitting... more

- by Jorge Madias and +1
- •
- Energy Consumption, Electric arc furnace, EAF, DRI and HBI Production

Los productos largos para la construcción más usuales incluyen las barras de refuerzo de hormigón (cabillas o varillas en algunos países latinoamericanos), los alambrones para la producción de mallas
electrosoldadas y algunos otros usos, y los perfiles, ángulos, planchuelas, redondos y cuadrados pequeños para herrería.
Una tendencia generalizada en el mundo y en América Latina para las plantas que se concentran en este tipo de productos, ha sido la instalación de plantas cercanas a los mercados, basadas en acería eléctrica y laminadores combinados. Tratándose de productos de un valor agregado relativamente bajo, las plantas que los fabrican suelen concentrarse en tener costos operativos bajos y alta productividad. Sus equipamientos, prácticas operativas y gerenciamiento son diferentes
a los empleados en las plantas de productos largos especiales, destinados básicamente a la industria automotriz. En este trabajo se revisan algunas de las técnicas que se están aplicando en plantas nuevas y en modernizaciones de plantas existentes, tanto en los hornos
eléctricos como en las máquinas de colada continua y laminadores.

- by Jorge Madias
- •
- Electric arc furnace, Reinforcing bar, Billet casting, Ladle furnace

In this paper is analyzing the current operating conditions of one of electric arc furnace (EAF) in order to evaluate the best option to solve the energy consumption problem. Also we evaluate existing process' equipment performance and point to improvement opportunities. Recommendations for the best operating set-points to run its EAF efficiently are presented. For compensating the reactive energy and increasing the power factor are presented three solutions. By the proposed automation solutions of the auxiliary installations is obtained a substantial reduction of the energy consumption and the defects of mechanical nature. The SVC compensation solution of the reactive energy is the best one, but has also the highest costs.

- by Marcel Topor
- •
- Energy Consumption, Reactive Power, Electric arc furnace, Operant Conditioning

Cada varios años se realiza en un país diferente la Conferencia
Internacional de Ciencia y Tecnología de Acería. En esta oportunidad tuvo lugar en Dresde, Alemania. Participaron especialistas de los grupos
siderúrgicos globales así como de universidades y centros de investigación independientes. Las presentaciones reflejaron los avances en el conocimiento para la mejora de la calidad de los aceros existentes y la elaboración de nuevos tipos de aceros, entre ellos los automotrices. Además, se presentaron desarrollos para mejorar la eficiencia energética de los procesos y la reciclabilidad de los subproductos, así como los esfuerzos chinos e indios para la adaptación de tecnologías
occidentales.

- by Jorge Madias
- •
- Electric arc furnace, Continuous Casting, Ladle Refining, BOF Steelmaking

This paper presents a study of power quality problems created by a UHP electric arc furnace (EAF) operation at power system. We are analyzing an electric arc furnace of 100 t capacity used for steel melting, and the related steel treatment installation. The measurements have been made using the CA8334 three-phase power quality analyser. Experimental results show that the EAF are a substantial source of electric disturbances, such as voltage fluctuations, flicker, harmonics, and unbalance between phases. Improvement of the energetic performances of an electric arc furnace imposes a careful technical and economical analysis, for choosing the possible solutions for balancing the load on phases, improving the wave forms (current and voltage) and improving the power factor.

- by Sorin Deaconu
- •
- Power Quality, Power System, Economic analysis, Electric arc furnace

This paper presents a neural network tree regression system with dynamic optimization of input variable transformations and post-training optimization. The decision tree consists of MLP neural networks, which optimize the split points and at the leaf level predict final outputs. The system is designed for regression problems of big and complex datasets. It was applied to the problem of steel temperature prediction in the electric arc furnace in order to decrease the process duration at one of the steelworks.

- by Marcin Blachnik
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- Metallurgy, Electric arc furnace, Data Mining applications

El aumento de la producción de acero por la vía hornos eléctricos de arco, la tendencia a revestir las chapas de acero con cinc para prevenir su corrosión, aumentando así la proporción de chatarra galvanizada a disponer en el futuro, más las exigencias ambientales crecientes, son
factores que permiten prever que el reciclado de los polvos de hornos eléctricos de arco seguirá creciendo, más allá de la coyuntura actual.
Las alternativas disponibles son variadas pero tienen un costo. La colaboración entre las industrias del cinc y del acero, los desarrolladores de tecnología y los proveedores de equipamiento pueden aliviar la carga y aportar soluciones sustentables con beneficio para las empresas y la
comunidad.

- by Jorge Madias
- •
- Recycling, Waste recycling, Steel Making, Steel