From Iron Ore to Crude Steel: Mass Flows Associated with Lump, Pellet, Sinter and Scrap Iron Inputs

This paper presents mass accounting models that trace the flow of major individual elements from iron ore through to iron lumps, pellets or sinter, the transformation of these intermediate products into pig iron (PI) or direct reduced iron (DRI), and the transformation of PI and DRI into crude steel in a basic oxygen furnace (BOF) or electric arc furnace (EAF) with the addition of scrap iron or steel or varying purity. Account is taken of non-iron oxides (gangue), addition of fluxes, the production of slag, and iron losses in slag. Simple relationships are developed giving the flux requirements for and slag production from a BF for various iron inputs, and relationships are developed giving flux requirements, the production of slag, and iron yield as a function of the proportions of PI, DRI and scrap inputs to a BOF or EAF. The mass and flow analysis presented here, and the energy flow analysis presented in a companion paper, provides a foundation for tracking the impact on energy use and iron losses of alternative pathways that might be used in the future as part of a broad-based effort to reduce energy use and associated greenhouse gas emissions.