Distributions of Chromium and Sulphur between Carbon-saturated Ferrochrome and CaO-MgO-Al₂O₃-SiO₂ Slag

Abstract

Experiments have been made to measure the chromium and sulphur distributions between carbon-saturated Cr-Fe-C alloy and CaO-MgO-Al₂O₃-SiO₂ slag at 1 550 and 1 598 °C. The reduction of SiO₂ proceeds very slowly, so that its equilibrium is not attained within the present duration of run. However, the following reactions are so fast that the local equilibria corresponding to the progress of the SiO₂ reduction are attained.
[Cr]+1/2(SiO₂)=(CrO)+1/2[Si]
[S]+(MO)+1/2[Si]=(MS)+1/2(SiO₂)
Based on the above reactions, the chromium and sulphur distributions between metal and slag have been analyzed with respect to temperature, slag composition and optical basicity (Λ). The main equations obtained are as follows :
log(%Cr)[%Si]^1/2/[%Cr]=-3.59(N_CaO+0.5N_MgO-0.1N_Al2O323-N_SiO2)4260/T-0.02
log[%S][%Si]^1/2/(%S)=-3.69(N_CaO+0.6N_MgO-0.3N_Al2O3-N_SiO2)-29840/T+14.62
log[%S][%Si]^1/2/(%S)=14.9Λ-31270/T+24.96
The validity of these equations have been discussed in comparison with the data reported by the other investigators.