THE SLAG FOAMING PRACTICE IN EAF AND ITS INFLUENCE ON THE STEELMAKINGSHOP PRODUCTIVITY

IMEXSA steel has a four electric are furnaces (EAF) steelmaking shop w hich was originally designed to melt a DRI/scrap ratio of 80/20 for pr oducing steel slabs, but logistical and economical circumstances led t o a change in this ratio to 98.2/1.8. This decision brought about incr eases on specific consumptions of energy, electrodes, refractories and a loss of metallic yield among other items. In order to improve melti ng performance a study involving industrial measurements and thermodyn amic-kinetic aspects of slag foaming was carried out. Implementation o f a slag foaming practice gave very encouraging results in the main pr ocess variables; energy consumption decreased from 730 to 640kWh/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 content s in slag decreased from previous 36-40wt% values to 23-25wt% increasi ng substantially metallic yield. Overall process performance was impro ved and consequences of this program can be directly seen during secon dary refining process of steel in LF.