Effect of Stirring Energy and Rate of Oxygen Supply on the Rate of Hot Metal Dephosphorization

• Published in: ISIJ International Vol. 35; no. 11; pp. 1374 - 1380
• Main Authors: Mukawa, Susumu, Mizukami, Yoshimasa
• Format: Journal Article
• Language: English
• Published: Tokyo The Iron and Steel Institute of Japan 01.01.1995; Iron and Steel Institute of Japan
• Subjects: Applied sciences; dephosphorization of hot metal; desiliconization of hot metal; Exact sciences and technology; hot metal pretreatment; Iron and steel making; mass-transfer coefficient; Metals. Metallurgy; Other methods of steel making and pure ironmaking; Production of metals; rate determining step; rate of dephosphorization; reaction kinetics; Mass transfer coefficient; Inert gas stirring; Reaction kinetics; Steelmaking; Silicon; Experimental study; Dephosphorization; Molten metal treatment
• ISSN: 0915-1559; 1347-5460
• DOI: 10.2355/isijinternational.35.1374

Study was made on desiliconization and dephosphorization reaction kinetics at various size equipments. Coupled reaction model was employed to analyse rate determining step of desiliconization and dephosphorization reaction. In the case of desiliconization reaction, mass transfer process in hot metal phase determines the reaction rate. On the other hand, dephosphorization rate is controlled by mass transfer process both in hot metal and slag phase. Mass-transfer coefficient in hot metal phase km proportionally increased with 0.7 power of parameter ε/dC2, independently on the equipment size, where, ε, dC is stirring energy of hot metal and the diameter of the vessel, respectively. Apparent rate constant of dephosphorization kP'=ln([%P]i/[%P]f)/tf increased with increase in stirring energy ε' and rate of oxygen supply VO2 under the optimum relationship between ε' and VO2 which was predicted by model calculations, where [%P]i and [%P]f is initial and final phosphorus content and tf, refining time. This optimum relationship was expressed as the empirical relation, ε'=1.51VO22+3.31 VO2 under the condition of this study.