The forming of foaming slag in electric arc furnace by injection of coke breeze and rearrangement of melting procedure

Foaming practices are widely used in electric arc furnace operations for: - shielding electrode, - longer electrode life, - faster melting time. Besides above, foaming practice is also able to increase furnace yield because by carbon injection into slag of electric arc furnace, (FeO) content in slag descends and thus improves the quality of melting steel. The experiments of foaming slag were carried out in PT. Krakatau Steel - Slab Steel Plant 130 tonne electric arc furnace using the experimental melting procedures involving alternate DRI charging plan, coke breeze injection control, lime or dolomite addition control and slag height control. The results of heats in each of experimental melting procedures, namely: - existing melting procedures, - experimental melting procedure one, two, three and four. Were statistically analysed by using the MINITAB statistical package. The analysis showed that the new melting procedures resulted in : - a decrease in effective melting time, - a significant decrease (28% to 32%) in (FeO) content in slag, - a particularly notable decrease (16% to 28%) in gunning material consumption per ton liquid steel, - a decrease in electrode consumption per ton liquid steel (7%).