Dc arc melting furnaces

Abstract

The advantages of dc arc melting furnaces over ac furnaces in the production of high-quality refractories and conducting and insulating materials are discussed.Currently, the Arcterm and Comterm research and production firms are developers and suppliers of dc and ac arc melting furnaces; when in service, the use of these facilities provides a high rate of profit and a short payback time.Studies that were carried out for many years at VNIIÉTO (All-Union Research Institute for Electrothermal Equipment, Moscow, Russia) jointly with leading organizations in Russia in the field of ferrous and nonferrous metallurgies, production of refractories, and other sectors of industry, and the expertise gained in the use of various metal treatment equipment have led to the conclusion that dc arc furnaces can be effectively used in a whole range of technological applications.Dc arc furnaces provide economies in energy, materials, and environmental costs; their use improves labor conditions and provides routes towards reprocessing of slag wastes and extracting valuable metals from them. The dc arc furnacebased technologies allow production of high-quality metals and alloys, reduction of the operating cycle, and expansion in the product range.Dc arc furnaces are used to make low-carbon and stainless (in particular, tungsten-containing) steels, gray iron, high-strength vanadium cast iron; aluminum and aluminumbased alloys; copper and copper-based alloys; silver, cobalt, nickel, manganese, and ferroalloys. Using the dc arc furnace technology, depletion melting of the slag of nonferrous and noble metals, refining and other processes, such as ore-reducing melting of calcium silicate and calcium carbide, reduction of silicon (for solar power engineering and semiconductor industry), organosilicon synthesis, manufacture of electrofused corundum, electrode product graphitization, waste processing and extraction of valuables components, production of phosphorus, silicon carbide, and electrode mix can be carried out.In the wide range of technological processes that are realized using dc furnaces, in this paper we consider in some detail those concerned with the steel-making in dc arc furnaces, with a 30-year-long history in industrial service. AC ARC FURNACES (AAF) AS AN ALTERNATIVE TO DC ARC FURNACES (DAF)A promising trend in electric steel production -viewed from the standpoint of an energy and materials-efficient economy and marginal environmental impact -is the use of dc steel-melting furnaces or retrofitting of the existing ac arc furnaces to enable their powering with direct current.At present, the DAF design has made use of the best that was achieved in the years-long history of the AAF development, in particular, refractory materials for the lining, systems of charging materials to the furnace, metal processing technologies, etc. DAF can operate with a complete discharge of molten metal ("unbogged," in a specialists jargon), or with a partial discharge ("bogged down"). In steel-making, DAF can operate in an oxygen-blown regime. This ...

Modelling magnetohydrodynamic processes in DC arc steelmaking furnace with bottom electrodes

“…The molten metal movement in CFX is described by the Navier-Stokes equation (1) and continuity equation (2). 13 To describe the turbulent movement of the liquid, the standard k2e turbulence model (3)(4)(5) of CFX software was taken, with settings debugged in the following works. 10,11 The k2e turbulence model constants C m 50?09, C e1 51?44, C e2 51?92, s k 51?0 and s e 51?3 were chosen.…”

“…2 Compared with alternating current furnaces, they have a number of advantages: reduced emission of dust and gaseous pollutants (up to 50%), reduced electric energy consumption by 5-15%, reduced furnace loss of alloying components by 15-20%, etc. 3 The recent tendency in the development of this furnace type is the increase in heat size. 4 However, the increased liquid metal volume leads to a slowing down of chemical reactions and heterogeneity of the chemical composition in the bath.…”

Modelling of electrovortex and heat flows in dc arc furnaces with bottom electrode

“…The time with liquid steel present ranges from 15 to 60% of the total operation period depending on the steel type and the quality of starting raw material. [1][2][3][4] In this type of dc arc furnace, the vortex flow of liquid metal is the result of spatial unevenness of the current with the absence of an outer magnetic field. The current in the liquid creates a magnetic field, which causes vortex movement of the liquid.…”

“…Direct current arc furnaces with a bottom electrode have become more popular in recent years, as such furnaces are more profitable and environmentally friendly than ac arc furnaces. [1][2][3][4][5] A typical example by Danieli Corporation is given in Fig. 1.…”

3D Numerical Analysis of the Arc Plasma Behavior in a Submerged DC Electric Arc Furnace for the Production of Fused MgO

“…Studies in the field of metallurgy, production of refractories, and other industrial sectors have been carried out for many years. The expertise gained in the use of a variety of metal treatment equipment leads to the conclusion that DC electric arc furnaces (EAF) can be effectively used in many technological applications [1] . A twin-electrode DC submerged electric arc furnace (SAF) was designed for MgO-crystal production.…”