On the floating-up Velocity and the Loagulability of the Primary

Products in Si-Deoxidation in a Static Iron Bath

Abstract

For the deoxidation of iron melt with silicon, a study has been made to investigate the floating-up velocity of the particles of the primary product in the static iron bath and the coagulation of them on the way of floating-up.
The results obtained are as follows;
1) The floating-up velocity of the particles of the primary product consisting of components SiO₂ and FeO obeys better a velocity equation υ= (3/2)(Δρg/18η) x² rather than Stokes' equation υ= (Δρg/18η) x², where x is radius of a particle.
2) The so called “local reaction heat effect” is possible to stimulate thegrowth of the primary products by coagulation in the early period of deoxidation. Therefore, when the amount of reactant or added silicon is large which would increase the heat effect, and the agitation is strong, the number of coarse particles will increase.
As a result, the separation of the primary product from the bath becomes more rapid with the increase of added silicon.
3) When the amount of added silicon is small, the coagulation of the products is poor in the early period of deoxidation because of the small heat effect. However, the separation of the products is as rapid as in the case of the large amount of added silicon, for there issome composition range favourable for the coagulation on the way of floating up in the bath.
4) The amount of added silicon does not essentially affect the floating-upremoval rate of the primary product in high silicon range.
5) When the concentration of the suspension of the inclusion particles in the bath is high, all the particles contribute almost equally to the coagulation on the way of floating up independently of radii.
6) In case that the primary deoxidation products are some oxide mixtures, the constitution of chemical composition of the particles has a considerable influence on the floating-up removal rate from the bath.