EAF Process Research Articles

Energy optimization of the electric arc furnace for operations at a fixed electrical power level

This paper presents an optimal control problem (OCP) that finds the optimal voltage and impedance setpoints that improve the electrical efficiency of an EAF for operations at a fixed power level. In the optimization framework, an electric arc model and an EAF process model are embedded into a dynamic optimization framework that aims at minimizing the radiation losses of the process. A numerical case study shows a reduction of 5% of the electrical power consumption of the process and an increment of 2% in the energy efficiency. It is demonstrated that the electrical power consumption of the process can be reduced under a mono profile setting of the EAF.

Recovery of zinc from zinc oxide dust containing multiple metal elements by carbothermal reduction

A carbothermal reduction process simulating EAF process is used to handle the zinc oxide dust, and the zinc in the dust can be extracted and recovered efficiently. The crude zinc and lead-tin alloy were obtained finally. The effects of temperature, holding time, and reductant dosage on zinc volatilization rate were investigated, and the ?Pelletizing - Calcination- Carbothermic reduction? experiment was conducted. The results found the optimal reduction condition was as follows: the temperature of 1300?, reductant dosage of 14.04%, and holding time of 120 min. After the calcination at 900? for 120 min, the removal rates of fluorine, chlorine, and sulfur in the dust were 98.18%, 96.38% and 28.58% respectively, and the volatilization rate of zinc was 99.83% in the reduction process. The zinc content of the crude zinc was 68.48%.

Effect of Carbon Materials on the Slag Foaming in EAF Process

Effect of Carbon Materials on the Slag Foaming in EAF Process

Circular Economy in EAF Process: How to Make It Sustainable with Zero Waste Project in Ferriere Nord

Circular Economy in EAF Process: How to Make It Sustainable with Zero Waste Project in Ferriere Nord

전기로 공정에서 슬래그 중 산화철의 환원 회수에 관한 연구

전기로 공정에서 슬래그 중 산화철의 환원 회수에 관한 연구

Updated Resource Depletion Characterization Factors for Life Cycle Assessment-Case Studies on Iron and Steel Production in China

In this study, the CML model for resource depletion was updated based on the current status of the mineral resources and the characteristics of relevant statistics in China; and the characterization factors of resource depletion were determined for the majority of natural minerals which are most used in materials industry. Besides, case studies on iron and steel production (BF-BOF and EAF process) were carried out to demonstrate the valid of the modified and localized resource depletion model. The results show that in terms of category, the development of Chinese steel industry is mainly based on the depletion of the natural iron ore and fluorite. The results also show that for BF-BOF process, abiotic resource depletion potential (ADP) in 2012 is 5.26 times of that in 2004; and for the EAF process, ADP in 2012 is 23.6 times of that in 2004. Therefore, the information of ADP needs to be updated at intervals of time.

Graph Model for Carbon Dioxide Emissions from Metallurgical Plants

Mathematical models are presented for estimating carbon dioxide emissions from metallurgical processes. The article also presents a new mathematical model in graph form to calculate transit and net emissions of carbon dioxide based on the estimates obtained for the individual processes. The graph model is used to compare the blast-furnace–converter process with the blast-furnace–EAF process.

Influence of direct reduced iron on the energy balance of the electric arc furnace in steel industry

A model of the EAF energy efficiency was developed based on a closed mass and energy balance of the EAF melting process. This model was applied to industrial EAFs in steel industry charged with scrap or with mixes of scrap and DRI. Complex mass and energy conversion in the EAF was simplified with the introduction of mass and energy conversion efficiencies for the conversion of oxygen and the energy conversion of electrical energy in the electric arcs, chemical energy from the oxidation reactions in the melt and energy from the combustion of burner gas. It turned out that close agreement with observed process parameters from 16 EAFs is obtained by slight variations of the efficiency values. Especially the sensitivity of the steel temperature from the energy conversion efficiency of the electric arc energy indicates the importance of efficient foaming slag operation in EAF steel making. Characteristics and process parameters of DRI charged EAFs are discussed. Model results for a series of case studies illustrate the correlations between DRI chemical composition, DRI portion, oxygen consumption, etc. with electrical energy demand in order to indentify cost-effective EAF process conditions.

대만(臺灣)의 EAF 더스트(전기로(電氣爐) 제강소진(製鋼紹塵))의 처리(處理)에 관하여

대만의 제강생산량은 21,290천톤이고, 전기로제강량은 제강생산량의 약 반, 즉 11,200천톤이다. 그리고 이 전기로 제강시 발생되는 더스트량은 160천톤(2009년도)이다. Walcz 프로세스(탄소강 EAF 더스트)에서 약 70천톤, RHF/SAF 프로세스(스테인레스강 EAF 더스트)에서 약 60천톤을 처리하고 있다. 그리고 약 90천톤/년의 조산화아연(ZnO)이 생산되고 있는 것으로 추정된다. 현재 새로운 EAF 더스트 리싸이클링법이 개발되고 있고, 조산화아연의 품위향상이 앞으로 과제이다. Taiwan's annual steel production reached 21.29 million tons. EAF accounted for about half of this total, or 11.2 million tons in 2008. The other 10.09 million tons came from blast furnace and converter process methods. The annual EAF carbon steel production is about 9.76 million tons, and the quantity of dust generated from the EAF process is 160 thousand tons, or about 16kg of dust per ton of steel was produced. In 2009, there is Walez process for carbon steel EAF dust recycling, and the capacity is about 70,000 tons per year; and there is RHF/SAF process for stainless steel EAF dust, the capacity is 60,000 tons per year which is enough to treat stainless steel EAF dust in Taiwan. There are many new treatment facilities processes will be that introduced to recycle the EAF dust in the near future, these processes will perform smoothly and successfully in Taiwan. The estimation of recycled crude ZnO is about 90,000 tons each year. The recycling and upgrading crude zinc oxide will be the next important issue in Taiwn zinc and steel industry.

Monitoring of radionuclides in carbon steel blooms produced by EAF process

Because natural and artificial isotopes in steel might originate from steel scrap or from the residue of the material that was used in the technological process, thus monitoring especially artificial radionuclides 60Co, 137Cs and 192Ir deserve special attention. The analysis by g-spectrometry has been applied to determine the presence of natural isotopes 40K, 226Ra, 232Th and 238U as well as of the artificial isotope 60Co, 137Cs and 192Ir and their activity in the produced steel round blooms in the Steel Mill of CMC Sisak d.o.o. At the same time the content of radionuclides in the other materials (ferroalloys, bauxite, fluorite, lime, coke, graphite electrodes, refractory blocks) used in the same steel making process was investigated. The measured values regarding the presence of individual isotopes and their activity in steel were as follows: 40K all values were less than 1.6 Bqkg-1; 232Th all activities values were less than 0.02 Bqkg-1; 226Ra all activities values were less than 0.01 Bqkg-1; 238U all activities values were less than 1.10 Bqkg-1; 60Co all activities values were less than 0.02 Bqkg-1; 192Ir all activities values were less than 0.02 Bqkg-1 and 137Cs all activities values were less than 0.30 Bqkg-1.

Process and practice of reducing the Cr loss during EAF with De-P hot metal charging for melting stainless steel

Based on practice, the main factors affecting the process of EAF with De-P HM charging have been theoretically analyzed, such as using oxygen, the material charging and making slag. Based on the process features of EAF with De-P HM charging, EAF productivity increase was achieved with application of the integrated control theory on EAF process in Baosteel Stainless Steel Branch.

AUMENTO DAS PLANTAS CONSTEEL® NO MUNDO: FLEXIBILIDADE PARA A CARGA CONTÍNUA DE GUSA LÍQUIDO E SUCATA NO FORNO ELÉTRICO A ARCO AGORA NA SIDERURGIA BRASILEIRA

This paper describes the latest big Consteel® applications around the world and the perspectives of utilization of this recognized technology on the recovery of the growth of the Brazilian Steel Industry, with particular attention to the utilization of hot metal as main part of the charging mix. The Consteel® EAF process represents the extension of the advantages of continuous charge feeding and melting process – typical of EAFs charged with 100% DRI – to the charging of scrap. This with the additional benefit of an “environmentally friendly” preheating of the charge help the reducing energy requirements of the process. Moreover the possibility of injecting oxygen for 100% of the power-on time makes the Consteel® process the best option for taking most of the advantages coming from hot metal charging in an EAF. Process details and technological peculiarities of this particular type of operation are described

Process and Practice of EAF with De-P Hot Metal Charging for Melting Stainless Steel

The article introduce the process of Electric Arc Furnace with Dephosphorized hot metal charging for melting stainless steel in Baosteel stainless steel Branch. Based on the practice of production, The main factors affecting the process of EAF with De-P HM charging are theoretically analyzed, such as using oxygen, the material charging and making slag. The optimization of hot metal charging can advance the use of chemical and physical energy, reduce the consumption of power. The optimization of using oxygen can increase the use of chemical energy. The optimization of material charging can reduce the oxidation of Cr. Making foamy slag can advance the transformer capacity and the use of power. Based on the character of the process EAF with De-P HM charging for Melting Stainless Steel, EAF productivity increased were reached with application of integrated control theory on EAF process in Baosteel stainless steel branch.

Advanced EAF oxygen usage at Vallourec-Mannesmann Saint-Saulve steelworks

Oxygen usage has played a crucial role in the ongoing EAF process improvement and has enabled furnace operators to optimize the chemical energy input, reaching unprecedented efficiencies and productivity. This article will present the fundamental principles governing the design of an optimized chemical energy system through scrap oxy-cutting and melting, decarburisation, post-combustion and slag foaming. It will be illustrated with industrial results obtained at the Vallourec Mannesmann Saint-Saulve site, where a PyreJetTM and ALARCTM PC system, using the newly designed DRAGON Panel, has been recently commissioned.

Pilot assessment of the airtight EAF process

Pilot assessment of the airtight EAF process

Pilot assessment of the airtight EAF process

Standard EAF operate with a large amount or air ingress (on the order of 30 000 Nm3 for 150 t of steel). This air is at ambient temperature thus, the nitrogen content and the non-reactive oxygen are only heated through the furnace and exit with the fumes at high temperature (1000°C). This brings about significant thermal losses. Reference and airtight trials were carried out with the 6-t EAF of Arcelor Research for assessing the gains related to airtight furnace operation.

Advanced EAF oxygen usage at Saint-Saulve steelworks

Tailored oxygen use has played a crucial role in EAF process improvement, enabling furnace operators to optimise chemical energy input, to achieve high efficiency and productivity. The fundamentals underlying an optimised chemical energy system, involving scrap oxycutting and melting, decarburisation, post-combustion and slag foaming, are described. This strategy is illustrated with industrial results obtained at the Vallourec and Mannesmann Saint-Saulve site, where a PyreJet and Alarc PC system, using the newly designed Dragon panel, has been recently commissioned.

Minimization methods for emissions generated from sinter strands: a review

The agglomeration of iron ores or fine-grained recycled high-grade iron materials is an essential part of the integrated iron and steelmaking process. The 15 European countries produce more than 100 Mt of sinter per year. However, environmental regulation is becoming more stringent, and therefore, sintering plants are under pressure to minimize their generated emissions, because they are the most polluting processes. Different possibilities have been suggested to solve this problem, e.g. using imported pellets or briquettes in blast furnace or to use EAF process. Such changes are very expensive and also delete the recycling route of the by-products, thereby creating an additional treatment or disposal problem. In this paper, different methods for minimizing emissions generated from sinter strands are reviewed.

EAF Process Monitoring at OneSteel's Sydney Steel Mill

Monitoring was conducted at OneSteel's Sydney Steel Mill electric arc furnace to study the effect of hot briquetted iron (HBI) upon furnace performance. Results from this study have been previously published by Trotter [1]. These studies were then continued for zero HBI operation to investigate the effects of a new, more reliable coke injection system into the slag and the change from two consumable oxygen pipes to a water‐cooled oxygen lance and the installation of a spray‐cooled roof. The investigations were comprised of an energy balance across the furnace, foaming slag investigations with regard to thermal efficiency and acoustic noise, effect of equipment modifications on the primary fume analysis, harmonic measurement for slag foam indicator, triboelectric system for measuring off‐gas dust loading. Each of these investigations is detailed in this report.

Foaming Behavior of CaO-SiO2-FeO-MgOsatd-X (X=Al2O3,MnO, P2O5, and CaF2) Slags at High Temperatures.

The foaming index was measured for CaO-SiO 2 -FeO-Al 2 O 3 and CaO-SiO 2 -FeO-MgO satd -X (X=Al 2 O 3 , MnO, P 2 O 5 , and CaF 2 ) slags to understand the foaming behavior. The foaming index of the CaO-SiO 2 -FeO-10Al 2 O 3 slags (C/S=0.93 and 1.2) decreases with increasing content of FeO up to 20 % and is almost constant for FeO content through 20 to 40 %. The viscosity of slags could be considered as the major contributor to foaming behavior. The addition of Al 2 O 3 into the silicate slags results in an increase of foaming index due to an increase of slag viscosity; this could be explained by the structural role of Al 2 O 3 in aluminosilicate slags. In the MgO-saturated and Al 2 O 3 -containing slags, FeO behaves as an acidic oxide, because slag melts would be more basic than MgO-saturated and non-Al 2 O 3 slags, where FeO behaves as a basic oxide, due to Al 2 O 3 enhances the dissolution of MgO into the slags. The addition of MnO into the MgO-saturated slags decreases foaming index, simply due to a decrease of slag viscosity. However, the addition of CaF 2 and P 2 O 5 into the slags results in the complex foaming behavior of slags; this is probably due to the Marangoni effect. The relationships between foaming index and the physical properties of slags can be obtained from the dimensional analysis as follows: Σ=214 μ/√ pO (for the CaO-based slags) Σ=999 μ/ √ O (for the MgO-saturated slags) The foam height is predicted as a function of decarburization rate from the molten iron and the contribution of slag foaming in EAF process was discussed as a function of decarburization rate.