ARAVIND GOLI

The removal phosphrous should be done after the removal silicon only

The one most important removal material during the processes of steel making otherwise it forms a iron phosphide its brittle in nature.

In Ellingham diagrame Fe and p are clos to each other.These lines widely can separated by adding storng basic flux i.e LIME

For effctive removal p ,we have to employ “high basicity”.Basicity incresed by adding lime

Soda ash is 100 times superior to lime but in practise we don’t prefer bcoz of its high corrosive action

Phosphorous oxidation is Highly exothermic reaction

The low temparatures are best suitable for removal phosphorous bcoz at higher temparatures the Reversion of phosporoustakes place.

Dephosphorising index(DP):it’s the ratio of phophorous content in the slag to phophorous content in the metal.

Its higher for high basicity slag and higher for oxidising of slag.

Dp propotional to basicity & Iron oxide(Feo) and inversely propotional to the TEMPARATURE

De phophosrization done under oxidising conditions only

If silicon is less den sulphur content high vice versa in pig iron

If less temp in the blast f/c the silicon reduction decresed,it leads to more viscous slag

Cac2,Cao,Na2o…etc,these are elements mix in pig iron to remove the sulphur

The maximum level of sulphur is 0.020%

Sulphur we have to maintain as low as possible 10ppm(0.001%)

If the temparature of the blast furnace is high,leads to high silicon content in the pig iron since at high temparature silica reduction is incresed

De-siliconized by

Laddle de-siliconizing by oxygen lancingin a transffer laddle

In active mixer by maintaing a suitable basic salg

In acid bessmer proccesse by partial blowing

We can remove the silicon by adding flux

Now a days removal of silicon takes place by “Tarpedo laddle”

Hot metal is taken in tarpedo laddle,scarpadded to it the reactions takes place during the processes and forms slag its skimmed off….