Thermodynamical Considerations on the Transfer of Si in Blast Furnace

Abstract

In the case that FeO content in the blast furnace type slag controls the oxygen potential of the slag-metal system, Si content of iron in the hearth of blast furnace is higher than the equilibrium Si content calculated.
Furthermore, the rate of the reduction of Si0₂ from molten slag by iron saturated with carbon is very slow, that is r_si≠^10-5mol/cm²·min. Consequently, it seems to be unable to explain that Si content in pig iron produced from the practical blast furnace can reach to 0.5-1.0% by only the slag-metal reaction.
It is proposed that the gas-molten metal reaction is predominant as the transfez of Si in the blast furnace.
From the thermodynamical calculations, it has been deduced that Psio has the order of 10^-2-10^-3 atm. in strongly reducing atmosphere of high temperature and low oxygen pressure such as the region adjacent to the tuyer zone in blast furnace and that SiO is sufficient source of Si.
It is considered that carbon content of iron plays an important role in themechanism of Si transfer.