Interfacial Phenomena in Metal–Slag–Gas System during AOD Process

Abstract

Significance of interfacial phenomena and properties such as surface tension are essential in iron and steelmaking processes due to chemical reactions occurring on the interfaces including elements transfer through the phase boundaries. In this study, the influences of surface tensions of slag and metal and interfacial tension between slag and metal on the behavior of metal–slag–gas system were analysed based on the energy bound to system surfaces. Effects of reactions between slag and steel on the behavior of metal–slag–gas system during AOD process were evaluated by two cases: evaluation of top slag–steel melt system and single bubble rising in the metal bath.
Simulations for metal–top slag system show that there are no possibilities to form metal film around the gas bubbles when they penetrate through metal–slag interface. Behavior of system is also independent of intensity of reactions between slag and steel. According to the calculations during intensive metal–slag reactions metal droplets are disintegrated more easily into top slag layer. If there are no metal–slag reactions metal droplets are attached into the gas bubbles.
Calculations prove that, when reactive oxygen gas bubble forming oxides is injected into steel bath, slag film can be formed around the gas bubble if the intensity of reactions between the slag and the metal is high. During effective oxidation reactions at the vicinity of nozzles formed micro slag is attached with the rising gas bubble.