The data obtained on 220-T ultra-high power electric arc furnace (EAF) were analysed in order to study the impact of DRI quality on the steelmaking process parameters and consumption of lime, coke, oxygen, natural gas, electrical energy and electrodes. In addition, the effects of charging methods and proportions of DRI in an EAF were studied. It was found that by increasing the proportion of non-high quality reduced pellets and/or HBI to 45% of the metallic charge, the steel yield decreased to 85.32% and increased to 87.57% when between 75 and 100% continuous feeding of high quality reduced pellets. This resulted in saving 21 min in tap-to-tap time and 7% of the electrode consumption. Charging high proportion of non-high quality DRI from 45% to 100% in EAF, leads to a loss of 4 tons/heat in liquid steel, and an increase in lime consumption from 4 to 6 kg/ton liquid steel.

Slag and the corresponding hot metal samples were collected just before tapping from electric arc furnace of Ezz Flat Steel Company (EFS) and analyzed. The temperature of hot metal was measured before tapping.The analyses of slag and hot metal together with the metal temperature were used to estimate the activity coefficient and activity of total ferrous oxides in slag, also investigate carbon and oxygen activity coefficient in steel according to the statistical theory of regular ionic solutions.The oxides capacity of the slag was also assessed. The variation of carbon and oxygen activity in hot metal with the concentration was also treated.The ratio of activity to concentration of total ferrous oxides is constant and equal to 0.0179. The activity coefficients of oxygen and carbon in steel are 0.810 and 1.0704, respectively.The oxides capacity of the slag increases with increasing carbon concentration in the bath and with increasing DRI proportion in the charge.