日本金属学会誌

J. Japan Inst. Metals, Vol. 55, No. 8 (1991),
pp. 860-866

Mass Transfer in Gas Phase for Decarburization of Liquid Iron by CO2-CO Gas Mixtures

Nagayasu Bessho1, Shoji Taniguchi2 and Atsushi Kikuch2

1Research Student, Tohoku University, Sendai. Present address: Kawasaki Steel Corporation, Chiba
2Department of Metallurgy, Faculty of Engineering, Tohoku University, Sendai

Abstract:

The rates of decarburization of liquid iron by CO2-CO gas mixtures were measured to discuss the mass-transfer characteristics in the gas phase for a system of reaction between an impinging jet of gas and liquid iron stirred inductively in a crucible under various conditions (concentration of carbon in liquid iron ≥q0.2 mass%, gas flow rate=(0.83~4.17)× 10-5 m3 NTP•s-1, mol fraction of CO2=0.1~1.0, diameter of nozzle=(0.66~1.32)× 10-2 m, temperature=1773~1973 K, and frequency of furnace = 9.0, 480.0 kHz.).
Results obtained are as follows:
(1) The decarburization rates under the above experimental conditions depend upon factors such as the gas flow rate, the concentration of CO2 in gas phase and the nozzle diameter which affect the gas-phase mass transfer. While the rates are affected hardly by the temperature which affects the chemical reaction, and also are independent of the concentration of carbon in liquid iron and the frequency of furnace which affect the mass-transfer rate in liquid. From these, it is shown that the decarburization is controlled by the mass transfer in the gas phase.
(2) Sherwood numbers Sh(=kGd/DAB) obtained from observed values of rates and a rate equation of the gas-phase mass transfer are correlated by an equation,


(Received 1991/2/27)

Keywords:

decarburization rate, liquid iron, crucible, mass transfer in gas phase, mass-transfer coefficient, Shewood number


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