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

Abstract

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 [formula omitted], 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 [formula omitted] increased with increase in stirring energy ε′ and rate of oxygen supply [formula omitted] under the optimum relationship between ε′ and [formula omitted] 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, [formula omitted] under the condition of this study. © 1995, The Iron and Steel Institute of Japan. All rights reserved.