A Study on Preheating Temperature and Oxidation Characteristics of Steel Scrap in EAF Operation

An eco-friendly, new type of electric arc furnace(EAF) that utilizes its off gas to preheat the iron scrap, the primary raw material of the furnace, has been recently developed. Scrap preheating furnaces consume up to 30% less energy than conventional EAFs. This study investigated how the off-gas dust collection rate and the type of scrap used in the recently developed EAF affect the preheating temperature of the scrap and its oxidation rate. A 1/6 linear scale model of the ecological and economical arc furnace(ECOARC) owned by Dongkuk Steel was constructed and tested. Steel scrap was charged into the preheating shaft of the EAF and preheated using its off-gas. The scrap preheating temperature depended on the off-gas dust collection rate and type of scrap used. It increased in the order of turnings, lightweight scrap, shredded scrap and heavy scrap. The scrap oxidation rate also depended on the type of scrap used and increased in the same order as the scrap preheating temperature. At the preheating temperature of the turnings, the oxidation rate of the scrap was almost of turnings fed to the newly developed EAF, the ratio of carbon to oxygen within it can be controlled.