Chromium Recycling from Argon-oxygen Decarburization Dust in Hot Metal Pre-dephosphorization Process

The chromium recycling from the stainless steel dust of an argon-oxygen decarburization (AOD) furnace during a hot metal pretreatment process was investigated. Experiments at different temperatures or with different amounts of AOD dusts were carried out in a laboratory furnace equipped with MoSi2 heating elements and subsequently industrial experiments were conducted in a stainless steelmaking factory, in order to study the thermodynamic mechanism of C and Si reacted with Cr2O3 to get Cr from AOD dust. The results showed that the reaction between C and Cr2O3 occurred below 1572. 18 K. Although its reducing ability was weaker than that of Si, C enabled the Cr in Cr2O3 in the AOD dust to be recycled using the Si in the slag. By combining the AOD dust added in an earlier stage, the hot metal pretreatment slag added in a later stage could not only recycle Cr from AOD dust but also remove Si, S, and P. Higher hot metal temperatures resulted in higher Cr content and lower remained P concentration in the molten iron.