Foamy slag practice to enhance the energy efficiency of electric arc furnace: An industrial scale validation

Abstract

The aim of the present work is to demonstrate the importance of foamy slag practice during steelmaking in electric arc furnaces (EAF). Steel making practices with foamy slag in the EAF not only reduces the energy consumption but it also protects the refractory materials of furnace linings from the high energy intensity generated by electrodes. It also decreases the noise pollution in conjunction with reduced melting time during the process. Foamy slag practices in electric arc furnace operations persists since long in steel making industries but here authors tried to modify the aforesaid practice at the concern plant in most economical way without impairing the steel quality.In the present study a process-controlled feeding of fine metallurgical coke for optimized foaming has been developed and simultaneous increment in energy efficiency has been noticed by collecting and analyzing the process related data. To carry out the present study more than 140 heats have been taken into consideration, with and without foamy slag generation in electric arc furnace. Considerable reduction in the electrical energy consumption (i.e. from ∼510 kwh per tone to ∼450 to 460 kwh per tone) has been noticed along with the reduction in total melting time from ∼87 min to ∼76 min. Present work also confirms that optimized met coke injection in the range of 15–18 kg/tone certainly helps in increasing the foaminess of the slag. FeO content of the slag was also assessed and found in the range of 17–21 wt% having the basicity of 1.8–2.2, which is a good agreement in prospects of yield as well as quality of the steel.