a) Calculate the time required to float  deoxidation product through a  2 meters steel bath height from the following data:

Density of liquid steel and  and  viscosity of liquid steel

      

Size of deoxidation product = 10micron 50 micron and 100 micron

Repeat the calculation when de oxidation product is silica and its density is
Interpret the result and get a feel about the importance of size of de oxidation products on velocity.

b)  Aluminum, titanium and zirconium are the strongest deoxidizers compared with manganese. Deoxidation with either aluminium or zirconium or titanium shows a minimum solubility of oxygen in steel. Determine the expression to calculate the value of Al in weight percent at minimum oxygen content  in Fe-Al-O system

Given:    and

Let us consider the following reaction;

(1)

                                                                                  
Assume activity of alumina, , since it is pure,

(2)

                                                
Substitute  and  and expression for  and  in equation 2. Differentiate the expression 2 with respect  to get



For the minima  and  we get



The readers may substitute the values of the interaction parameters to get a feel of the value of Al and to understand the role of interaction parameters in calculations.