Silicon in hot metal from a blast furnace, the role of FeO

Silicon [Si] in hot metal is an impurity acting in the steel shop as an energy source that is released by oxidation during oxygen blowing in the converter. Preferred silicon concentration in hot steel is typically 0.4 wt-% (± 0.1 wt-%), helping predictable and low-cost processing. In practice, the Si concentration is difficult to control and may occasionally reach levels higher than 1 wt-%. The authors studied data from observations, samples and autopsies of a chilled blast furnace, a core drill and a furnace in operation. In addition, production data from a melting reduction pilot plant (HIsarna) and FactSage® calculations were used. The amount of FeO in the raceway, the area in which hot gas and powdered coal (PCI) are introduced in the blast furnace, in relation to [Si] in hot metal, is observed. The goal of this paper is to contribute to a better understanding about the mechanism of the dissolution of silicon in hot metal.