PHOSPHOROUS BEHAVIOR IN ELECTRIC ARC FURNACE STEELMAKING WITH THE MELTING OF HIGH PHOSPHOROUS CONTENT DIRECT REDUCED IRON

Traditionally, scrap has been the raw materials feed to the electric arc furnace, but increasingly direct reduced iron (DRI), pre reduced pellets and hot briquetted iron (HBI) are being focused as potential alternative charge materials for the electric arc furnace. The partial substitution of scrap by these charge materials directly affecting on the quality of steel and process consumptions in electric arc furnace. Whereas DRI/HBI products have low contents of copper, nickel, nitrogen, sulfur, etc., they can contain large amounts of phosphorus. Depending upon the quality of ore used to produce the DRI/HBI; these products can contain five to ten times as much phosphorus as scrap. Most commercially available DRI/HBI materials commonly contain between 0.03 to 0.09 % phosphorus as compared with 0.015 to 0.02 % for scrap. The goals of this research are to contribute to a more complete understanding of the behavior of Phosphorus with melting of direct reduced iron (DRI and HBI) having phosphorous content 0.061 wt %, and thermodynamics of phosphorus transfer in metal - slag (or DRI/HBI gangue) systems. The experiments have been conducted at EZZ Flat Steel Company in Egypt, with annual production 1.2 mln. The thermodynamic and statistical analysis showed that, the dephosphorization reactions sufficiently far from equilibrium, and the continuous feeding of metalized materials (DRI and HBI) hinders the phosphorous removal process and decreases the distribution of phosphorous between slag and metal. For optimum dephosphorization with using the metalized materials having high phosphorus content 0.061 wt %, the slag should have 25-30 % FeO, 4% MgO, slag basicity preferable being between 2.5-3 and temperature - 1625-1635 degrees C