The Slag Foaming Practice in EAF and Its Influence on the Steelmaking Shop Productivity

Abstract

IMEXSA steel has a four electric arc furnaces (EAF) steelmaking shop which was originally designed to melt a DRI/scrap ratio of 80/20 for producing steel slab, but logistical and economical circumstances led to a change in this ratio to 98.2/1.8. This decision brought about increases on specific consumptions of energy, electrodes, refractories and a loss of metallic yield among other items. In order to improve melting performance a study involving industrial measurements and thermodynamic-kinetic aspects of slag foaming was carried out. Implementation of a slag foaming practice gave very encouraging results in the main process variables; energy consumption decreased from 730 to 640 kWh/t of steel while electrode consumption decreased from 2.25 kg/t of steel to 1.81 kg/t of steel. With regard to iron oxidation, iron oxide contents in slag decreased from previous 36-40 wt% values to 23-25 wt% increasing substantially metallic yield. Overall process performance was improved and consequences of this program can be directly seen during seconday refining process of steel in LF.