Production of Low-P Steel

Production of low phosphorus steel using the basic oxygen steelmaking process is typically achieved by maintaining a highly basic slag, which leads to increased flux consumption, significant slag volume, and challenges in slag recycling due to the presence of free lime. This process also poses environmental concerns related to mineral resource depletion, fossil fuel consumption, and CO2 emissions. Recent studies suggest that satisfactory dephosphorization can occur in the basic oxygen furnace (BOF) even with reduced slag basicity (from 3.3–3.6 to 2.7–2.8). The findings indicate that phosphorus partitioning deviates from the equilibrium, and post-stirring significantly helps in decreasing bath phosphorus levels. Additionally, the induction furnace, often used for structural grade steel production, typically employs acidic lining that is less effective for phosphorus removal; however, the adoption of basic lining has demonstrated potential for producing low phosphorus steel. The article revisits the strategies of phosphorus removal, emphasizing optimal slag composition and post-stirring techniques as effective methods for enhancing dephosphorization efficiency.