Carbon Powder Mixed Injection with a Shrouding Supersonic Oxygen Jet in Electric Arc Furnace Steelmaking

The method of carbon powder mixed injection with a shrouding supersonic oxygen jet was proposed to increase the utilization efficiency of carbon powder and improve the foaming slag operation during the electric arc furnace (EAF) steelmaking process by delivering the carbon powder more deeply into the molten bath. In this study, the fluid flow characteristics of the carbon powder mixed injection with a shrouding supersonic oxygen jet were studied and analyzed using numerical simulations, which were first validated by a cold test experiment. Compared with the conventional carbon powder injection without a shrouding jet, the shrouding supersonic oxygen jet can protect the central gas-powder jet against the entrainment of the surrounding atmosphere, increase the velocity of carbon powder and make the carbon powder cluster together in a longer distance. Furthermore, the industrial application research was carried out in a 50-ton commercial Consteel EAF, and the relative metallurgical effects were also studied. Compared with EAF steelmaking using conventional carbon powder injection without a shrouding jet, the powder consumption, tap-to-tap time, FeO content in the final molten slag and phosphorus content of the final molten steel were reduced by 19.3 kWh/ton, 4 min/heat, 2.6 pct and 1.2 × 10⁻³ pct, respectively, after using the method of carbon powder mixed injection with a shrouding supersonic oxygen jet.