Ar-CO<SUB>2</SUB>混合ガスによる溶鉄の脱炭反応機構

Abstract

A study has been made on the kinetics of the decarburization of liquid iron in Ar -CO2 atmospheres at 1600°C. The study has been especially directed towards determining the rate -controlling steps at low carbon contents of the melt.In the concentration range above 0.02-0.05% C (depending upon the partial pressure of CO2), the rate of decarburization is influenced by the gas flow rate. On the other hand, in the concentration rangebelow 0-02-0-05% C (depending upon the partial pressure of CO2), the rate of decarburization no longer depends on the gas flow rate, if it is higher than 1300 cc/min.The aspects on the mechanism of decarburization under the latter condition are summarized as follows;(1) The decarburization by blowing gas of pCO2 below 0.1 is controlled by chemical reaction. The rcactions conceived here are;. The results can be explained reasonably by the model based on the simultaneous reactions except for the range where FeO is formed on the surface of melt. The rate constants obtained here are; K1′= (1-2.5)×10-6mol/cm2sec atm2, k2= (2-3)×10-5 mol/cm2 sec atm.(2) At pCO2≥0-1, the rate-determining factor changes gradually. It is shown that at pCO2, ≥0.2, the rate of decarburization is determined by the mass transfer of carbon in liquid iron, mass transfer coefficient kc being 0.036 cm/sec.