Dephosphorization model for a continuous DRI-EAF process

For many steelmaking processes, mathematical modeling is an effective inexpensive way to predict the effects of changes in operational variables will have on the process. Several basic oxygen furnace (BOF) models have been developed over the years. In BOF steelmaking, the input materials are added at the beginning of the process, the metal and slag are tapped at the end, and the liquid bath is nearly homogeneous. In contrast, electric arc furnace (EAF) steelmaking operates with a liquid heel from the previous heat; fluxes, oxygen and carbon are injected continuously; and slag is semi-continuously flushed out. Clearly the EAF process is fundamentally different from BOF steelmaking. So far there have been few reports of modeling the phosphorus reaction in the EAF. Although many EAFs operate with scrap and pig iron, direct reduced iron (DRI) is increasingly used as input thanks in part to the lower prices of natural gas following shale gas development. In this work, a kinetic model for dephosphorization in DRI-EAF steelmaking has been developed. The model calculates the changes (with time) of slag composition, phosphorus (P) level of the steel, and the bulk & interface phosphorus partitions. This model is a part of ongoing research, thus, the presented results are preliminary.