Electric arc furnace EAF

Direct Reduction. Direct reduction processes are distinguished from other ironmaking processes in that iron oxide is converted to metallic iron without melting. Because this product, called direct reduced iron (DRI), is soHd, it is most suitable for melting in an electric arc furnace (EAF) as a substitute for scrap (see Furnaces, electric). The briquetted form of DRI, hot briquetted iron (HBI) is used when the product is to be transported. Briquetting increases density and chemical stabiUty. The predominant direct reduction processes (MIDREX and HyL III) are based on natural gas as a fuel and reductant source. They are economically attractive in regions where natural gas is cheap and abundant, especially if iron ore is available nearby (see Iron BY DIRECT reduction). ... 

The electric arc furnace (EAF) (together with the basic oxygen vessel) is one of... 

For the most part, the zinc materials recovered from secondary materials such as slab zinc, alloys, dusts, and compounds are comparable in quality to primary products. Zinc in brass is the principal form of secondary recovery, although secondary slab zinc has risen substantially over the last few years because it has been the principal zinc product of electric arc furnace (EAF) dust recycling. Impure zinc oxide products and zinc-bearing slags are sometimes used as trace element additives in fertilizers and animal feeds. About 10% of the domestic requirement for zinc is satisfied by old scrap. 

Electric furnaces, 12 286-318 76 144, 145. See also Electric arc furnace (EAF) Fuel-fired furnaces applications for, 12 315-316 arc furnaces, 12 297-306 classification of, 12 286 economic aspects of, 12 313-314 health and safety factors related to, 12 314 induction furnaces, 12 307-313 in phosphorus manufacture, 19 8-11 resistance furnaces, 12 287-297 for secondary slags, 14 759-760 Electric furnace steelmaking processes,... 

The ionic liquid ChCl with urea was applied to the processing of electric arc furnace (EAF) dust by Abbott and coworkers [18]. It was found that the solubility of ZnO, Cu O, and PbO was good, zinc and lead can be selectively removed and subsequently electrowon from the liquid, whereas the insoluble iron and aluminosilicates can be recycled through the electric arc furnace. The process developed for treating EAF dust involves extraction of lead and zinc from matrix, isolation of lead, and recovery of zinc. The pilot plant built for 5-kg dust extraction batches is given in Fig. 5.1 [19]. 

Fig. 5.1 Schematic diagram of the cell for extracting lead and zinc from electric arc furnace (EAF) dust together with a photograph of the pilot plant built for 5-kg dust extraction batches (Reproduced from Ref [19], with kind permission of The Royal Society of Chemistry)...

The BOS process replaced the Bessemer and open hearth steelmaking processes during the 1960 s and caused some major changes in both the steel and lime industries [27.1, 27.2]. The process is currently used for 70% of the world s steel production, with most of the remainder being in electric arc furnaces (EAF). The main processes in iron and steelmaking are illustrated in Fig. 27.1. 

Cast steel is normally melted in electric arc furnaces (EAF) or in coreless induction furnaces (IF). Once melted, the liquid metal can be refined (i.e. removal of carbon, silicon, sulphur and or phosphorus) and deoxidised (i.e. reduction of metallic oxides), depending on the base material and the quality requirement of the finished product. Figure 2.3 gives process flow diagrams for the melting and metal treatment of cast steel in the different furnace types. 

Steel is melted in both electric arc furnaces (EAF) and induction furnaces (IF). The choice between furnace types is based on technical criteria (e.g. capacity, steel grade). Due to its refining ability, the EAF allows the melting of lower grade scrap. This is an advantage in terms of the recycling of metals, but requires an appropriate flue-gas capture and cleaning system, as will be presented below. 

Electric arc furnace (EAF) dusts have become a significant source of feed for the ISP. These contain up to 35% Zn and environmental legislation in developed coxmtries is discouraging the previous practice of dumping EAF dusts. In a number of countries the Waelz process to produce zinc oxides treats these dusts. In some cases these oxides are hot briquetted as a direct feed for the ISF. An alternative method of treating steel plant and other dusts is to inject them directly into the furnace through the tuyeres. 

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