Ladle-Furnace-Slag Reprocessing at Evraz Nizhnii Tagil Iron and Steel Works OJSC

Abstract

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.