Energy Savings in the Melting Process of an Electric Arc Furnace

2000 ◽  
Vol 33 (13) ◽  
pp. 561-566
Author(s):  
Luís Gomes ◽  
Anikó Costa ◽  
Dirk Tilsner ◽  
Carlos Soares ◽  
Carmen Morgado
Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1069
Author(s):  
Marcus Sommerfeld ◽  
Claudia Vonderstein ◽  
Christian Dertmann ◽  
Jakub Klimko ◽  
Dušan Oráč ◽  
...  

Due to the increasing demand for battery raw materials such as cobalt, nickel, manganese, and lithium, the extraction of these metals not only from primary, but also from secondary sources like spent lithium-ion batteries (LIBs) is becoming increasingly important. One possible approach for an optimized recovery of valuable metals from spent LIBs is a combined pyro- and hydrometallurgical process. According to the pyrometallurgical process route, in this paper, a suitable slag design for the generation of slag enriched by lithium and mixed cobalt, nickel, and copper alloy as intermediate products in a laboratory electric arc furnace was investigated. Smelting experiments were carried out using pyrolyzed pelletized black mass, copper(II) oxide, and different quartz additions as a flux to investigate the influence on lithium-slagging. With the proposed smelting operation, lithium could be enriched with a maximum yield of 82.4% in the slag, whereas the yield for cobalt, nickel, and copper in the metal alloy was 81.6%, 93.3%, and 90.7% respectively. The slag obtained from the melting process is investigated by chemical and mineralogical characterization techniques. Hydrometallurgical treatment to recover lithium is carried out with the slag and presented in part 2.


Author(s):  
Eugenio G. M. Brusa ◽  
Nicola Bosso ◽  
Nicolò Zampieri ◽  
Stefano Morsut ◽  
Maurizio Picciotto

Prediction of structural dynamics of the Electric Arc Furnace (EAF) is rather difficult, because of a number of phenomena occurring during the scrap melting process. Three large electrodes, corresponding to each phase of a AC circuit, are lowered by the main mast towards the scrap to activate the melting process, induced by the electric arc. Electric current fed to each electrode produces a strong magnetic field and applies an electromechanical force on the other electrodes. Arc voltage looks irregular upon time, even because of the scrap motion within the vessel and temperature growth. The vertical position of the mast is controlled by an hydraulic actuator. Nevertheless, a heavy vibration of the structures affects the regularity of the melting process. A fully coupled model of the whole system is herein proposed, through a multi-physics approach. A first analytical approach, describing the electric circuit of the whole system, is implemented into a Multi Body Dynamics (MBD) model of the EAF, while a reduced Finite Element Method (FEM) model of the flexible structures is used for a preliminary optimization of the design parameters. Electromechanical forces due to the mutual induction among the electrodes are computed and the dynamic response of the system is investigated. Proposed model allows a first refinement of the EAF design, although a complete experimental validation on the real machine has to be performed, in spite of problems due the extremely difficult accessibility of structures during the melting process.


Author(s):  
S. Timoshenko ◽  
E. Nemtsev ◽  
M. Gubinski

Possibility of a wide choice of original charge and variation of oxidation potential in melting process makes the electric arc furnace (EAF) a general-purpose unit in foundries. Energy-intensive classical technology with insufficient specific power of the transformer, irregular operation with forced downtime predetermine a low energy efficiency of foundry class furnaces [1,2]. Flat and shallow bath of the EAF enhances the problem.


Author(s):  
Eugenio G. M. Brusa

Prediction of dynamic behavior of electrodes of the Electric Arc Furnace (EAF) fed by AC current is rather difficult because of several phenomena superposed, particularly during the first step of melting process, i.e. the so-called perforation, and in case of melting of metallic scrap. Unexpected ruptures of electrodes are often observed as a consequence of vibration. Dynamic excitation is applied by the vertical position control of the mast supporting the electrodes and by the Lorentz’s forces generated by the magnetic flux provided by each electric phase. Moreover, the irregular distribution of stiffness along the electrode, being due to the sensitivity of material properties upon temperature, affects quite a lot the dynamic response of the structure. To identify the origin of the observed ruptures and to suitably predict the dynamic behavior of the whole system a modeling activity was performed. A numerical model of the EAF structures was built, by resorting to an integrated approach based on the Finite Element Method and on the Multi Body Dynamics, then it was preliminarily validated on an existing plant. It demonstrated that stiffening effect upon the graphite electrode induced by temperature distribution makes dangerous the action of the vertical position control, when it is applied too fast and excites the flexural modes of the electrode. Numerical model allowed refining the design of the electrode and improving the safety factor as well as finding some design requirement to suitably limit the operation of the position control system.


2020 ◽  
Vol 170 ◽  
pp. 02012
Author(s):  
Sandeep Ohol ◽  
Mathew VK ◽  
Savita Shinde ◽  
G. Balachandran

The current study deals with optimizing the melting process used in electric arc furnace by heat balance equations. Heat balance is a very important aspect in an arc furnace in which the energy input consists of electrical energy [65%], chemical energy [25%] and exothermic reaction heat [10%]. This energy is optimized with the charge mix, charge quantity, fluxes, fuel used, and O2 used in the burners. The present model considers all these aspects and gives heat distribution in the process. The model spreadsheet gives a reasonable prediction in terms of metal yield, composition, and energy consumption. The model also predicts the amount of iron oxidized in the process. The mass and heat balance model is a useful tool for process analysis and improves the process efficiency of electric arc furnace steelmaking.


Author(s):  
Eugenio G. M. Brusa ◽  
Stefano Morsut

Vibration of electrodes in Electric Arc Furnace (EAF) fed by AC current for steel melting is usually fairly large. It might be dangerous for the EAF operation and often reduces the efficiency of melting process. Vibration amplitude depends on the vertical position control operated to keep the arc length constant as much as possible and to the electromechanical actions due to the mutual magnetic induction among the three electric phases. Since designer of the EAF system needs a clear correlation between each design parameter and the dynamics observed a first modeling activity was performed. A mechatronic approach was implemented, by including the electromechanical coupling into the structural analysis performed to predict the system dynamics. A Multi Body Dynamics (MBD) code was used in cooperation with the Finite Element Method (FEM). A preliminary experimental validation on a real plant was tentatively performed.


Author(s):  
J. R. Porter ◽  
J. I. Goldstein ◽  
D. B. Williams

Alloy scrap metal is increasingly being used in electric arc furnace (EAF) steelmaking and the alloying elements are also found in the resulting dust. A comprehensive characterization program of EAF dust has been undertaken in collaboration with the steel industry and AISI. Samples have been collected from the furnaces of 28 steel companies representing the broad spectrum of industry practice. The program aims to develop an understanding of the mechanisms of formation so that procedures to recover residual elements or recycle the dust can be established. The multi-phase, multi-component dust particles are amenable to individual particle analysis using modern analytical electron microscopy (AEM) methods.Particles are ultrasonically dispersed and subsequently supported on carbon coated formvar films on berylium grids for microscopy. The specimens require careful treatment to prevent agglomeration during preparation which occurs as a result of the combined effects of the fine particle size and particle magnetism. A number of approaches to inhibit agglomeration are currently being evaluated including dispersal in easily sublimable organic solids and size fractioning by centrifugation.


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