The present paper deals with a kinetic study of decarburization of liquid Fe-Ca lloy in CO-CO
2 atmospheres at 1 600°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 0.05%C, the rate of decarburization is influenced by the gas flow rate.
It is shown that at carbon content higher than 0.1-0.15%, the decarburization controlled by gaseous diffusion.
In the concentration range below 0.05%C, the rate of decarburization no longer depends on the gas flow rate, if it is higher than 1 300cc/min. The views on the mechanism of decarburization under this condition are summarized as follows;
(1) The decarburization by blowing gas of the ratio pco, /pco below 1/4 is controlled by chemical reaction.
The rcactions conceived here are;C+CO
2k
1→k
1′2CO
3, CO
2k
2→k
2′CO+O, C+Ok
3→k
3′The results can be explained reasonably well by postulating appropriate values for k
2, k
3′, k
1′/
k3′.
(2) At higher gas ratio (Pco
2/Pco≥1/4), the rate-determining factor changes gradually.It is shown that at pco
2, /pco≥7/3, the decarburization is controlled by the mass transfer of carbon in liquid iron, themass transfer coefficient being 0.036cm/sec.
抄録全体を表示