1970 Volume 56 Issue 8 Pages 998-1013
In order to pursue a possibility of application of metallic gas bubble to the cleaning of iron and steel melt, a study was made of the deoxidation characteristics of Ar-Ca gas bubble floating up in iron melt. The results of this study will also give some fundamental information on the behavior of complex deoxidizider containing calcium. The results obtained are as follows;
1) At 1550°C, e (Ca) O=-535, e (O) Ca=-1330 for interaction parameter, log KCa=log aCa·aO=-9.82 for equilibrium constant KCa of a reaction [Ca] + [O] =CaO, and log [%Ca] [%O] /PCa (atm) =-3.86 for the equilibrium relation between the melt and Ca vapour pressure.
2) [O] decreased with increase of the amount of Ca added in a form of straight line in the range of high oxygen content ( [O] >150 ppm) and in a form exponential line in the range of the low content ( [O] <100 ppm). It could be interpreted that the reaction Ca-O was controled by the supply of calcium from the bubble to reaction place in the former and by the supply of oxygen from the bulk of the melt to the place in the latter.
3) The melt deoxidzed with Ar-Ca gas bubble was free from the product CaO, probably owing to removal of it with the bubble, and it was easy to attain to high efficiency of calcium utilization by increasing of floating distance of the bubble.