1992 Volume 78 Issue 2 Pages 231-238
Dephosphorization of molten high chromium iron with CaO-based flux is investigated in a laboratory scale test and industrial AOD test.
By using CaO-CaF2-CaCl2-Fe2O3 flux of about 100 kg/t, dephosphorization of 70% is possible in the crucible test, if the molten iron with a chromium content of 16% has a carbon content of 6%. In the AOD test, dephosphorization of 50% is achieved at a carbon content of about 3.5% with CaO-CaF2-Fe2O3 flux.
The reason why the degree of dephosphorization decreased at low carbon content in the melt is considered to be mainly due to the decrease in phosphorus activity. It is considered that high viscosity slag by the increase in Cr2O3 content also retards the dephosphorization rate.
To get satisfactory dephosphorization, (T·Fe) content should be controlled to 24% with CaO content of 2030%. Phosphate capacities of the slags (CPO43-=(%PO43-)/(PP21/2·PO25/4)) are 10201021 at 1500°C.
It is seen that dephosphorization of molten high chromium iron resulted from higher oxygen potential in the slag than that in metal.
