Electric Furnace Research Articles

Evaluation of the Performance of Advanced Refractory Materials Intended for the Roof of an Electric Furnace for High-Level Waste Vitrification

Evaluation of the Performance of Advanced Refractory Materials Intended for the Roof of an Electric Furnace for High-Level Waste Vitrification

Experimental study on structural performance of 7A04-T6 high-strength aluminium alloy shear connections in and after fire

The present study addresses the structural behaviour and design of 7A04-T6 high-strength aluminium alloy double shear connections under elevated temperatures and post-fire conditions with air cooling. A total of thirty-three connection specimens, featuring different fastener types and geometric characteristics, including end distances and edge distances, were tested under varying temperature histories, ranging from 20 to 400 ℃. An electric furnace was employed to heat the connection specimens, while digital image correlation (DIC) technology was employed to record displacements of the specimens during testing. Three distinct failure modes were observed in the tested specimens, namely the bearing, shear-out, and net section tension failures. The experimental results obtained from this study were compared to the predictions generated by the current design methods outlined in the American specification (AA), European standard EN 1999–1-1 (EC9) and Chinese code GB 50429 (GB). The comparisons revealed that the design rules often exhibit conservatism in predicting the ultimate resistances of 7A04-T6 high-strength aluminium alloy shear connections under elevated temperatures and post-fire conditions. Notably, EC9 emerged as providing the most accurate predictions for both resistances and failure modes of the investigated shear connections.

A thermodynamic model for predicting activity of CaO–SiO2–Al2O3–MgO–TiO2–V2O3–FeO slags during electric furnace smelting process

A thermodynamic model for predicting activity of CaO–SiO2–Al2O3–MgO–TiO2–V2O3–FeO slags during electric furnace smelting process

Carbothermal Reduction of Oil Shale Residue (OSR) in DC Electric Furnace to Prepare Si–Al–Fe Alloy

Carbothermal Reduction of Oil Shale Residue (OSR) in DC Electric Furnace to Prepare Si–Al–Fe Alloy

In-situ observation of molten brazing filler metal permeating gap

Generally, brazing is completed when the brazing filler metal permeates the gap by uniform wetting. It is believed that the joining process is completed with the formation of joint defects ‘voids’ in the process of uniform wetting. However, previous studies have shown that what occurs when brazing is performed is non-uniform wetting. It is suggested that this non-uniform wetting is the cause of void generation. Wetting and spreading of brazing filler metal is tested on a metal plate, as described in JIS Z 3191. This is used to investigate the wetting of the brazing filler metal. However, this method does not cover the wetting of the molten brazing filler metal as it moves into the gap. Therefore, it is suggested that the JIS Z 3191 experiment is insufficient to evaluate the wetting of the molten brazing filler metal that penetrates into the gap. In this experiment, we created new specimen. It is called us ‘V-groove specimen’. Specimens were created with two base metals. They are pure copper and lead-free brass in which bismuth was used as an alternative element. In order to do in situ experiments, it was not possible to observe the inside of a conventional electric furnace. Therefore, we produced a furnace with a window for in-situ observation and experimented with it. As a result of experiments with V-groove specimens, it was found that there are two types of wetting of brazing filler metal. They are called ‘primary wetting’ and ‘secondary wetting’. The shape of the specimen was measured and evaluated for two types of wetting. The results showed that the primary wetting was measurable in shape and spread evenly. However, the shape of the secondary wetting could not be measured, and it was found to be non-uniformly spread.

Waste control by waste: Extraction of valuable metals from mixed metallurgical dust by boiling furnace roasting

Electric arc furnace dust (EAFD) is a hazardous waste by-product generated during the process of electric furnace steelmaking, which is rich in valuable metal elements. In order to solve the problem of environmental pollution and resource utilization of EAFD, we propose a new process for medium-temperature suspension roasting EAFD and coke dry quenching dust to extract valuable metals. The thermodynamic properties and migration behavior of valuable elements involved in the reaction were analyzed using thermodynamic simulation software FactSage8.1 and thermogravimetric mass spectrometry. The mechanism and kinetic equation of the dezincification process were investigated using the Kissinger method and Coats-Redfern model. The impact of various parameters on the process efficacy and ash fusion characteristics of the material were investigated through boiling furnace experiments. The results demonstrate that elevating the reaction temperature and decreasing the zinc partial pressure is more favorable for reducing and separating zinc. The corresponding kinetic equations for the decomposition of ZnFe2O4 and reduction of ZnO are denoted as dα/dT = 1.69 × 1012exp (−3.37 × 104/T) and dα/dT = 6.76 × 106 exp (−2.08 × 104/T) × (1 − α) [−ln(1 − α)]3/4, respectively. The optimum reaction temperature was 1050 °C, the C/O ratio was 0.8, the reaction time was 40 min, and the ventilation rate was 3500 mL/min. Under these conditions, the material had no liquid phase agglomeration, and the removal rates of zinc and lead were 93.38 % and 98.14 %, respectively. The crude zinc dust with a zinc grade of 87.57 % and the alloy slag with an iron grade of 52.38 % was obtained. The new process utilizes the excellent heat transfer characteristics and fluidization conditions of the boiling furnace to efficiently realize the high-grade recovery of valuable metals in the EAFD, which provides new insights for the clean treatment of zinc-containing waste.

Effect of annealing treatment of indium tin oxide thin films on film properties and transparent antenna properties

There is a growing demand for transparent thin film antennas to serve as access points for wireless communication that can be installed at any location without compromising visibility, while retaining the versatility of existing antennas. Although studies exist on indium tin oxide (ITO)-based transparent antennas, studies on the effect of thin-film process parameters on antenna properties are rare. In this study, we deposited ITO, which resonates at 3.3 GHz, using the facing target sputtering method with different thicknesses ranging from 400 to 2000 nm, from a typical thin film to a relatively thick film. ITO thin films deposited at room temperature were annealed in air at 200, 300, and 400°C in an electric furnace. The optically transparent monopole antennas were fabricated using air-annealed ITO films. The effects of the annealing temperature on the film and antenna properties were investigated. A high radiation efficiency of 70.8% was achieved while maintaining a transmittance of more than 70% for a 2000 nm ITO film annealed at 400°C. The results indicate that tailoring appropriate conductive film properties for desired transmittance is crucial to realize the expected antenna performance.

Magnetic biochar catalyst from reed straw and electric furnace dust for biodiesel production and life cycle assessment

A novel magnetic carbon-based catalyst was prepared from solid waste (reed straw and electric furnace dust) by coprecipitation and high temperature pyrolysis with excellent application potential. Single factor and response surface experiments were used to optimise the catalyst preparation process (mass ratio of reed straw/electric furnace dust of 5:1 at 500 °C in 4 h) and biodiesel production, respectively, with results of 99.89 wt% biodiesel yield in the first cycle (93.61 wt% after 11 cycles) obtained at 74.15 oC in 4.16 h with a 14.06:1 molar ratio of methanol/oil and 7.75 wt% catalyst. The life cycle assessment of magnetic carbon-based catalysts for biodiesel production suggested that the soybean oil extraction stage had the greatest impact on the environment, mainly from the use of soybeans and electricity. Solid waste as raw material to prepare catalysts for biomass energy conversion was proven to be a good strategy for energy conservation and emission reduction. This study provides guidance sustainable biomass energy conversion with low cost, low energy consumption, and minimal negative environmental impact.

Modeling and development of technology for smelting a complex alloy (ligature) Fe-Si-Mn-Al from manganese-containing briquettes and high-ash coals

Investigation of the possibility of obtaining a complex master alloy used in the deoxidation of steel, smelted from substandard manganese-containing materials, briquettes, and high-ash coals in ore-thermal electric furnaces. Thermodynamic modeling was carried out using the HSC Chemistry software package to determine the optimal process parameters using a second-order rotatable plan (Box-Hunter plan). Thermodynamic modeling improves the understanding of physical and chemical processes, allows making predictions about the behavior of the system under various conditions, optimizing processes and saving time and resources necessary for experiments. Electric smelting of the briquette was carried out with coal and quartzite (to adjust the chemical composition and neutralize residual carbon) in an ore-thermal electric furnace with a power of up to 150 kV*A. The influence of temperature on the equilibrium distribution of silicon, manganese, and aluminum in the «briquette-coal-quartzite» system, the degree of transition of silicon and manganese into a complex ligature and the content of these metals in the alloy are determined by the method of thermodynamic modeling. As a result of experiments on ore-thermal electric smelting of a briquette with high-ash coal, a complex ligature was obtained with an average content of 45.92–53.11% silicon, 27.72–34.81% manganese and 5.60–6.91% aluminum.

Rancang Bangun Mesin Extruder Plastik

This research explores the potential of a plastic extruder machine as a solution to address plastic waste by utilizing high temperatures to melt and form plastic blocks. The machine aims to determine the optimal temperature for the production of plastic pellets. Despite initially producing plastic liquid, the machine is expected to effectively reduce plastic waste.
 The machine specifications involve an electric motor, gearbox, melting furnace, intake, melting spiral, output, pulley, and V-belt. Analysis of electric motor planning determines the required power. Gearbox planning involves gearbox ratio and required torque. Planning for pulleys and V-belts is conducted to transmit power from the motor to the machine's drive system. Planning for shafts and bearings was also carried out.
 The plastic extruder machine holds promise as a significant solution for plastic waste recycling. The manufacturing cost of the machine is found to be Rp17,349,350 and can be further reduced with a more optimal design. Recommendations for future research include enhancing detailed analysis and utilizing a richer set of references.

Electromagnetic processing of molten copper alloys in the induction furnace with cold crucible

Electromagnetic processing of molten copper is provided in a special kind of electrical furnace called an induction furnace with a cold crucible (IFCC), making it possible to successfully remove impurities from the workpiece. In order to analyze the process in a sufficient way not only electromagnetic, thermal and flow but also metallurgical and mass transfer phenomena in the coupled formulation should be taken into consideration. The paper points to an analysis of the kinetic process of lead evaporation from molten copper. It was shown that mass transport in the gas phase determines the rate of the analyzed evaporation process. The possibility of removal of lead from molten copper is analyzed and described.

An Interpretable Time Series Forecasting Model for Predicting NOx Emission Concentration in Ferroalloy Electric Arc Furnace Plants

Considering the pivotal role of ferroalloys in the steel industry and the escalating global emphasis on sustainability (e.g., zero emissions and carbon neutrality), the demand for ferroalloys is anticipated to increase. However, the electric arc furnace (EAF) of ferroalloy plants generates substantial amounts of nitrogen oxides (NOx) because of the high-temperature combustion processes. Despite the substantial contributions of many studies on NOx prediction from various industrial facilities, there is a lack of studies considering the environmental condition of the EAF in ferroalloy plants. Therefore, this study presents a deep learning model for predicting NOx emissions from ferroalloy plants and further can provide guidelines for predicting NOx in industrial sites equipped with electric furnaces. In this study, we collected various historical data from the manufacturing execution system of electric furnaces and exhaust gas systems to develop a prediction model. Additionally, an interpretable artificial intelligence method was employed to track the effects of each variable on the NOx emissions. The proposed prediction model can provide decision support to reduce NOx emissions. Furthermore, the interpretation of the model contributes to a better understanding of the factors influencing NOx emissions and the development of effective strategies for emission reduction in ferroalloys EAF plants.

Numerical Simulation of the Hydrogen-Based Directly Reduced Iron Melting Process

In the context of carbon reduction and emission reduction, the new process of electric arc furnace (EAF) steelmaking based on direct hydrogen reduction is an important potential method for the green and sustainable development of the steel industry. Within an electric furnace for the hydrogen-based direct reduction of iron, after hydrogen-based directly reduced iron (HDRI) is produced through a shaft furnace, HDRI is melted or smelted in an EAF to form final products such as high-purity iron or high-end special steel. As smelting proceeds in the electric furnace, it is easy for pieces of HDRI to bond to each other and become larger pieces; they may even form an “iceberg”, and this phenomenon may then worsen the smelting working conditions. Therefore, the melting of HDRI is the key to affecting the smelting cycle and energy consumption of EAFs. In this study, based on the basic characteristics of HDRI, we established an HDRI melting model using COMSOL Multiphysics 6.0 and studied the HDRI melting process, utilizing pellets with a radius of 8 mm. The results of our simulation show that the HDRI melting process can be divided into three different stages: generating a solidified steel layer, melting the solidified steel layer, and melting HDRI bodies. Moreover, multiple HDRI processes are prone to bonding in the melting process. Increasing the spacing between pieces of HDRI and increasing the preheating temperature used on the HDRI can effectively reduce the aforementioned bonding phenomenon. When the melting pool temperature is 1873 K, increasing the spacing of HDRI to 10 mm and increasing the initial HDRI temperature to 973 K was shown to effectively reduce or eliminate the bonding phenomenon among pieces of HDRI. In addition, with the increase in the melting pool temperature, the time required for melting within the three stages of the HDRI melting process shortened, and the melting speed was accelerated. With the increase in the temperature used to preheat the HDRI, the duration of the solidified steel layer’s existence was also shortened, but this had no significant impact on the time required for the complete melting of HDRI. This study provides a theoretical basis for the optimization of the HDRI process within EAFs.

Synergistic Activation of Electric Furnace Ferronickel Slag by Mechanical Grinding and Chemical Activators to Prepare Cementitious Composites.

The use of electric furnace ferronickel slag (FNS) as a supplementary cementitious material is the current focus of research. This study investigates the effect of mechanical grinding and chemical additives on the activity excition of FNS, as well as the associated synergistic mechanisms. This study shows that the addition of triethanolamine (TEA) increases the fine-grained content in FNS powder, which facilitates the depolymerization of FNS and the early hydration of aluminum tricalcium. Furthermore, the addition of Ca(OH)2 raises the alkalinity of the cementitious system, which promotes the availability of Ca2+ ions and accelerates the hydration process, resulting in the generation of additional hydration products. The enhancement of late hydration of C3S by TEA and its combination with the secondary hydration of Ca2+ at high alkalinity are the pivotal factors to improve the strength of cementitious composite. A mixture of FNS and 0.03% TEA is subjected to grinding for 90 min, using the obtained micropowder which replaces 20% of the cement, and subsequently, after being excited with 3% Ca(OH)2, the FNS micropowder reaches the quality standards of S95 slag powder. It is worth remarking that the micropowder prepared by mixing FNS with 3% Ca(OH)2 and 0.03% TEA and grinding it for 81 min also meets the S95 standard for slag powder. The larger dosage of FNS in cement is supported by the observed synergy between TEA and Ca(OH)2. This research will provide valuable insights for the expanded application of FNS in construction materials.

A Pharmaceutical Study of Rasasindoora in Perspective of Different Time Pattern

In the system of Ayurveda, there are two basic categories of medicinal formulations-Kashtaushadhi (pure herbal) and Rasaushadhi (herbo-mineral). The standardization of Rasaushadhies through modern parameter gives an easy acceptance and can remove the negative propaganda about medicine containing Parada (mercury). Rasasindoora is widely prepared and clinically practiced by Ayurvedic fraternity. Aims and Objectives: The current study is planned to established the best pharmaceutical method of Rasasindoora in perspective of time and cost. Materials and Method: 250gm Kajjali was taken in every bach for the preparation of Rasasindoora by using EMF (electric muffle furnace) with the thought it gives desired and standard yield. In this study 3 batches of Rasasindoora were prepared in 16 hours, 11 hours and 8 hours. Result: Rasasindoora yield from Batch I, Batch II and Batch III are 50.84%, 51.76% and 50.48%. Conclusion: The average yield is 51.02% and yield from batch III (8hrs) is 50.48%, there is no major difference in % yield in all three batches. Thus, the best adopted method for the preparation of Rasasindoora is batch III (8hrs) due to lesser consumption of electricity, coal and time.

Analyzing the Mechanical and Durability Characteristics of Steel Slag-Infused Asphalt Concrete in Roadway Construction

Steel slag is a solid byproduct of the steelmaking process, widely generated in the metallurgical industry. Due to its alkaline nature and excellent adhesive properties with asphalt, it represents a potential road construction material with outstanding road performance, making it well-suited for utilization in highway construction. This paper conducts a systematic analysis of the physical and chemical properties of steel slag, specifically South Steel Electric Furnace slag, and compares it with natural basalt and limestone aggregates. The aim is to establish a foundation for the application of steel slag in asphalt mixtures. Building upon this foundation, we carry out proportioning design for AC-13C and SMA-13 steel slag asphalt mixtures, followed by a comprehensive study of their high-temperature stability, low-temperature stability, water stability, and fatigue performance. Our research reveals variations in the chemical composition of different steel slags, with CaO, SiO2, and Fe2O3 being the primary components. The content of harmful elements varies depending on the steelmaking raw materials and additives used. Notably, the optimum asphalt-to-aggregate ratios for AC-13C and SMA-13 significantly surpass the specified requirements. The freeze–thaw splitting strength ratio and residual stability of steel slag AC-13C and SMA-13 asphalt mixtures exceed the specified requirements, with AC-13C demonstrating the highest water stability, boasting a freeze–thaw splitting strength ratio of 94.07%, and a residual stability of 93.8%. In terms of fatigue characteristics, SMA-13 exhibits a longer fatigue life than AC-13C, indicating superior fatigue performance for steel slag SMA-13. Steel slag enhances the abrasion resistance and rutting resistance of asphalt pavement surface layers, fully meeting the performance requirements for high-grade road surface layers.

FeS-assisted restructuring of zinc-bearing phases into sulfated compounds for efficient zinc extraction from hazardous electric furnace dust

Electric arc furnace dust (EAFD) is a hazardous solid waste generated as a byproduct in the steelmaking process, containing significant amounts of zinc and iron, making it a primary secondary source of zinc. The separation of zinc and iron in an environmentally-friendly and efficient manner poses a crucial technological challenge for the safe disposal and resource utilization of EAFD, facilitating the recovery of valuable zinc and the direct reuse of iron as raw materials for ironmaking. In this study, a novel method for restructuring zinc-bearing phases into sulfated compounds through low-temperature roasting by introducing FeS in EAFD were proposed. Simultaneously, the iron-containing phases undergo a transformation into Fe2O3. Subsequently, efficient separation of zinc and iron is achieved through a leaching process using dilute sulfuric acid. The conditions for the theoretical transformation of zinc-containing phases into ZnSO4 and iron-containing phases into Fe2O3 in EAFD were determined by thermodynamic calculations incorporating FeS. The temperature range for sulfation calcination was determined to be within 550–700 °C based on TG-DSC analysis and the evaluation of SO2 release during the decomposition of FeS. The optimal conditions for the roasting process were determined as an E/F ratio of 1:3, a temperature of 650 °C, and a duration of 3 h. In addition, the optimal conditions for the leaching process were determined as the addition of 1 mL of 1 M H2SO4 and a liquid–solid ratio of 25 mL/g. Under these conditions, the extractions of Zn and Fe reached 95.33 % and 0.17 %, respectively. The mechanism of phase reconstruction from zinc-containing phases to sulfate phases in EAFD was thoroughly analyzed, revealing that the Zn species in EAFD were transformed into Zn3O(SO4)2 through solid–solid and gas–solid reactions, while the majority of Fe species in EAFD and FeS were converted into Fe2O3. Effective separation of zinc and iron was achieved by dissolving Zn3O(SO4)2 in diluted sulfuric acid while retaining Fe2O3 in the residue. This study provides a fresh perspective on the recovery of zinc from zinc-containing solid waste resources, offering significant potential for the sustainable management and utilization of EAFD.

Optimizing capacitance performance: Solar pyrolysis of lignocellulosic biomass for homogeneous porosity in carbon production

This work compares the effect of using a solar reactor against a conventional electrical furnace to obtain carbon materials by pyrolysis of a lignocellulosic precursor. The solar reactor is directly irradiated and includes modifications to improve the control of the process and the reproducibility of solar experiments. A bagasse of agave creole was selected as the lignocellulosic precursor or biomass to obtain carbon materials at temperatures of 700 °C. Comparing carbons produced by conventional and solar pyrolysis, higher crystallinity and lower hydrophilicity are evident in the former. Moreover, conventional pyrolysis tends to promote a more homogeneous porous structure in comparison to solar pyrolysis. However, within the spectrum of solar carbons produced, the morphology of biomass plays a crucial role in influencing the chemical composition and porosity properties. Specifically, the use of fibers instead of powders to produce carbons through solar pyrolysis results in a more homogeneous porosity, attributed to an enhanced volumetric absorption of solar radiation. This modification leads to a significant improvement in capacitance, increasing from 125 F/g to 175 F/g at 5 mV/s in aqueous electrolytes. The carbons from the solar furnace are reproducible, underlying the potential of the proposed process towards a sustainable alternative. To achieve a theoretical reference, the pyrolysis process was mimic trough Reactive Molecular Dynamics calculations modeling the initial structural conditions of agave biomass with its corresponding lignocellulosic components and considering analogous thermal conditions. The resulting carbon structures at the end of the simulations showed structural properties that are consistent with those observed in the pair distribution functions obtained from XRD and the pore size distribution from physisorption analyses. This combined experimental–theoretical approach offers the potential to elucidate porous carbon structures derived from pyrolysis processes powered by solar radiation . This method can help in the design and identification of lignocellulosic structures in biomass, with the resulting carbon materials suitable for energy storage applications.

Energy-Technology Indicators of a Multi-Drum Electric Furnace for Firing Vermiculite Concentrates

The design and working process of a new electric drum furnace for heat treatment of vermiculite concentrates and conglomerates, as well as other bulk porous materials based on a silicate binder, are considered. The electric drum furnace is devoid of the disadvantages inherent in its predecessors – furnaces with a movable hearth platform: there are no oscillating elements, dynamic effects do not occur, and there is also no resonant mode of operation, since the working drums perform rotational motion with a constant angular velocity. Using the example of a six-drum furnace, the volumes of processed material located in the firing spaces are calculated, and the second and hourly productivity of the furnace (10 m3/h or 0.0029 m3/s) are determined. The temperature of the heating elements (1167 K) was calculated, the electric power of the furnace (95.2 kW) and the specific energy intensity of the firing process of vermiculite concentrate, with a dimension of 4 mm (0.004 m) from the raw materials of the Kovdorsky deposit – 44.2 MJ/m3, which makes the furnaces of the new design competitively capable, were determined.

Estimation and modeling of the biomass and carbon storage in the stump and root of Populus deltoides

Carbon storage in plant biomass is the simplest and most economically viable way to reduce atmospheric carbon dioxide carbon dioxide concentration. The objective of this study was to estimate and model the biomass and carbon storage of the stump and root in Populus deltoides trees in afforestation, Guilan Province of Iran. For this purpose, 93 trees with 25 years old were selected from different diameter classes and after cutting and removing the sections, an excavator was used to unearth the stumps and roots of the trees from the soil. In order to estimate the biomass and carbon storage of tree stumps and roots, samples of these components were isolated and weighed, and after drying in the oven, the dry weight of the samples was measured. The carbon content of stumps and roots of the trees were calculated after burning the dried samples in an electric furnace. The results showed that the biomass of stumps and roots was 7.99 and 65.5 kg per tree, respectively, and the carbon content of stumps and roots was estimated to be 3.92 and 32.32 kg per tree, respectively. The results of allometric equations showed that the models for estimating biomass and carbon storage of stumps and roots using the tree stump diameter variable had a high coefficient of determination, but the model using the stump height had no acceptable coefficient of determination. The evaluation results of different models also showed that the power model was more accurate than other models. In general, the results showed that the carbon stored in stumps and roots was 1.568 and 12.928 tons per hectare, respectively.