Reducing the use of Fossil Carbon and Fuels to Defossilize the Electric Steelmaking Route: Evaluation of the Effects of Alternative C-Bearing Materials and Hydrogen in the Electric Arc Furnace

Electric steelmaking is pivotal for the transition toward carbon-lean processes. Replacing fossil carbon and fuels with alternative non-fossil materials can contribute to enhancing the sustainability of this route. The investigations reported in this paper explore the use of alternative carbon sources for slag foaming in the Electric Arc Furnace (EAF) and the utilization of hydrogen in related burners. The effects of using alternative carbon sources are investigated via industrial trials and complementary simulations employing a flowsheet model of the entire electric route. The investigations demonstrate that, although alternative carbon materials can generally lead to fossil CO2 reduction of up to 15% without negatively affecting the product or most process aspects, high ratios of certain materials, such as 30% tires, can compromise operational safety and result in poor slag foaming. Concerning hydrogen use in burners, preliminary simulations show that CO2 reduction of up to 48% can be achieved in off-gases before post-combustion, accompanied by water vapor increases of up to 31%. Simulations also estimate an increase in hydrogen content in tapped metal of up to twice the reference value; however, this increase can be mitigated by standard vacuum degassing procedures.