Comparison of Refining Characteristics in Hot Metal Treatment by Bottom Injection with Top Blowing Using Soda Ash

Abstract

Hot metal refining using the flux containing Na₂CO₃ was studied on a laboratory scale by comparison of bottom injection method with top blowing method using argon or oxygen gas as a flux carrier.
Excellent desulfurization performance could be obtained by the bottom injection method, particularly on using argon gas as a flux carrier. This was due to a increase in flux/metal interfacial reaction area which was estimated about 3 times as large as that of top blowing method. However, efficient phosphorous removal could not be achieved by the bottom injection method because the reaction of Na₂CO₃ with C took place instead of the reaction of Na₂CO₃ with P, especially in the region of low phosphorous content level. On the other hand, in the case of top blowing, dephosphorization reaction proceeded to the extreamly low phosphorous content level without remarkable decarburization reaction.