Erwee, Markus WouterPistorius, Petrus Christiaan2012-10-052012-10-052012-07Erwee, MW & Pistorius, PC 2012, 'Nitrogen in SL/RN direct reduced iron : origin and effect on nitrogen control in EAF steelmaking', Ironmaking and Steelmaking, vol. 39, no. 5, pp. 336-314.0301-9233 (print)1743-2812 (online)10.1179/1743281211Y.0000000076http://hdl.handle.net/2263/20077In the steel plant considered here, direct reduced iron (DRI), produced by the coal based Stelco-Lurgi/Republic –National (SL/RN) process, makes up 50% or more of the total iron charge. The SL/RN DRI samples from a kiln cooler had high nitrogen contents (50-250 ppm, depending on particle size), contributing to elevated nitrogen levels in liquid steel produced in the electric arc furnaces. The proposed mechanism of nitriding of SL/RN DRI involves gaseous nitrogen (present within the rotary cooler) diffusing into the solid bed and is supported by a simple diffusion model. A strong correlation was found between the melt-in carbon content of the liquid steel and the final tap nitrogen content, with melt-in carbon of 0.3% C or higher resulting in nitrogen levels below 50 ppm at tap, even when charging DRI material that is high in nitrogen.en© 2012 Institute of Materials, Minerals and MiningRotary kilnDirect reduced ironNitrogen controlElectric steelmakingStelco–Lurgi/Republic–National (SL/RN)Steel -- MetallurgySteel -- Nitrogen contentSteel foundriesPostprint Article