Ar-CO-CO_2 ガスによる溶鉄の脱炭速度について

概要

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The decarburization rates of liquid iron have been measured in the vavious Ar-CO-CO_2 mixtures by using the levitation technique. The concentrations of carbon and oxygen change mostly along the carbon-oxygen line in equilibrium with Ar-CO-CO_2 mixture under the condition that the oxide film is not formed on the surface of liquid iron. The reaction finishes at a concentration determined by P_<CO_2>/P_<CO>. The rate has been analyzed by assuming that the mass transfers between the two phases determine the overall reaction rate. The following rate equation has been obtained under the condition of n_C・n_O=constant ;[numerical formula] At the high concentration of carbon the decarburization rate is regarded to be controlled by the mass transfer in the gas boundary layer. The rate is gradually reduced, because the resistance of the mass transfer in the metal boundary layer increases and the driving force of the reaction decreases as the concentration of carbon becomes lower. The iron droplet exploded due to the formation of the oxide film on the surface at the high partial pressure of CO_2. For a short period at the beginning, the rapid reaction occurs to reduce both the concentrations toward the equilibrium line of P_<CO>+P_<CO_2> in Ar-CO-CO_2 mixture. The reaction can be satisfactorily explained by the mechanism that C-O degassing and decarburization take place at the same time during this stage.
社団法人日本鉄鋼協会の論文
1978-07-01