THE EFFECT OF STIRRING ENERGY AND THE RATE OF OXYGEN-SUPPLY ON THE RATE OF HOT METAL DEPHOSPHORIZATION

Study was made on the desiliconization and dephosphorization reaction kinetics at various size equipments. Coupled reaction model was employ ed to analyse the rate determining step of desiliconization and dephos phorization reaction. By model calculations, the rate determining step of desiliconization reaction is the mass transfer process in the hot metal and mass transfer both in hot metal and slag for dephosphorizati on reaction. The mass transfer coefficient in hot metal k(m) proportio nally increased with 0.7 power of parameter epsilon/d(c)2, independent ly on the equipment size, where, epsilon, d(c) is the stirring energy of hot metal and the diameter of vessel, respectively. Apparent rate c onstant of dephosphorization kp' = ln ([%P]i/[%P])/t(f) increased from 0.10min-1 to 0.33min-1, when stirring energy epsilon' and the rate of oxygen supply VO2 was increased under the optimum relationship betwee n epsilon' and VO2 which is predicted by the model calculations, where [%P]i and [%P]f is initial and final phosphorus content and t(f), ref ining time. This optimum relationship was expressed as the empirical e quation, epsilon' = 1.51 VO2(2) + 3.31VO2 under the condition of this study.