A Strategy for Partial Replacement of Lime by Limestone and Its Impact on Basic Oxygen Furnace Steelmaking

Abstract

Production of steel in a sustainable manner is gaining importance day by day. Optimizing fluxes in basic oxygen furnace (BOF) steelmaking, such as partial replacement of lime with limestone, can be a step toward this. The heat available in BOF can decompose the limestone which partially avoids the need for calcination in lime kiln. However, the size, quantity, and time of limestone addition in BOF are important parameters as they influence the decomposition behavior of limestone. The associated problems of slopping, presence of uncalcined limestone, fines generation, etc. are also influenced by these parameters. In the present study, laboratory experiments are conducted by changing the size, temperature, and time of exposure which help in understanding high‐temperature behavior of limestone. With these inputs, along with theoretical calculations, a trial is conducted in a 160 t BOF by limestone addition and replacing equivalent amount of lime. The study focusses on the benefits of limestone addition in BOF along with other aspects, that is, impact on blow profiles, slag condition, lining wear, etc. Characterization of slags help in explaining the improvement observed during this trial. The article presents the findings of laboratory studies and limestone addition trials and uniquely highlights its overall impact on BOF steelmaking.