Ladle-Furnace-Slag Reprocessing at Evraz Nizhnii Tagil Iron and Steel Works OJSC
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LADLE-FURNACE-SLAG REPROCESSING AT EVRAZ NIZHNII TAGIL IRON AND STEEL WORKS OJSC V. V. Temnikov,1 O. O. Sheshukov,2 M. A. Mikheenkov,3 and A. A. Metelkin4
UDC 658.567.1
Ladle furnaces at Evraz Nizhnii Tagil Iron and Steel Works OJSC produce over 90,000 metric tons of slag per year. As this slag cools, it turns into a fine-grained powder; if the powder cannot be sold, it is temporarily stored until it can be disposed of [1]. We have considered producing easily used flux sinter from the slag generated during ladle processing of steel (hereinafter, ladle-furnace slag or LFS). Since LFS still contains a large number of metallic inclusions, it cannot be included in sinter fed into a hammer mill via the enclosed lime feed trough. LFS was therefore added to the iron flux charge along with the steel smelting fluxes in a duplex and mono process (steel converter slag (SCS) and vanadiumbearing converter slag (VCS)); the fluxes are then crushed in a jaw crusher. A successful test of the use of LFS in sinter was performed, the charge was free of raw limestone, coke consumption was lower, sinter machinery production capacity was higher, and the weight/sample ratio of the sintered product was improved. Since SCS and VCS contain up to 3.0% V2O5, this provided an opportunity to increase vanadium use during the blast-furnace sintering process by more than 100 metric tons of vanadium per month. Key words: Ladle-processing slag, iron flux, steel converter slag, vanadium-bearing converter slag, commercial-grade vanadium.
Economical use of mineral raw materials throughout the mining and production process is an extremely important economic and environmental goal. Development of high-efficiency resource-conserving technologies requires economically sound extraction of primary and byproduct elements as well as recovery and reprocessing of manmade raw materials such as metallurgical slag. Metallurgical slag is a major byproduct of ferrous metals production, making up approximately 70–85% of all cast-iron and steel smelting waste [2]. Slag has an iron content of 25–30%, with some in bead form (11–15%). Slag recycling is a requisite for waste-free operations, since it enables recycling of old tailings, prevents generation of new tailings and the resultant need to use additional agricultural land, eliminates the inevitable dust generated by tailings, and prevents air and water pollution. Extensive use of ladle processing with high-calcium (maximum CaO 60%) refining slag has caused severe environmental problems in the areas of slag storage and reprocessing. After metallurgical use, removal from the ladle, and hardening, ladle slag undergoes what is known as “silicate decomposition” [3]. 1 2
Nizhnii Tagil Iron and Steel Works, Nizhnii Tagil, Russia; e-mail: [email protected].
Russian President B. N. Yeltsin Ural Federal University Federal State Independent Educational Organization, Ekaterinburg, Russia; e-mail: [email protected]. 3 Metallurgy Institute, Ural Department, Russian Academy of Sciences, Ekaterinburg, Russia; e-mail
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