Reducing dephosphorization of silicomanganese ferroalloys by CaO-based slag

The reducing dephosphorization of silicomanganese ferroalloys by CaO-based slags is investigated in the present paper. Experiments are carried out in an induction furnace in air atmosphere to simulate the practical production condition. It is found that dephosphorization took place very quickly by using CaO-CaF 2 slag. In addition, decarburization and desulfurization also happened with the dephosphorization process. There is almost no dephosphorization when the silicon content in silicomanganese ferroalloy melt is less than 10 wt.%, while the dephosphorization ratio increases significantly as the silicon content is larger than 10 wt.%. When CaF 2 in the slag is partly replaced by Al 2 O 3 , the dephosphorization ratio decreases sharply, and there is almost no dephosphorization for CaO-Al 2 O 3 slag even when silicon content in the ferroalloy melt is 22 wt.%.