Phosphorus Equilibrium Between Liquid Iron and CaO-SiO2-MgO-Al2O3-FeO-P2O5 Slags: EAF Slags, the Effect of Alumina and New Correlation

Abstract

The increased use of electric arc furnace (EAF) steelmaking using up to 100% direct reduced iron (DRI) has prompted an interest in better control of phosphorus since iron ore and, consequently, DRI have higher phosphorus and silica compared to scrap. There is limited work reported on slag chemistries corresponding to that in the EAF when DRI is used. In the current research, phosphorus equilibria between molten Fe–P alloys and CaO-SiO2-Al2O3-P2O5-FeO-MgOsaturated slags were investigated. The results indicate that there is a significant decrease in the phosphorus partition coefficient (LP) as alumina in the slag increases. The observed effect of alumina on the phosphorus partition is probably caused by the decrease in the activities of iron oxide and calcium oxide. Finally, an equilibrium correlation for phosphorus partition as a function of slag composition and temperature has been developed. It includes the effect of alumina and silica and is suitable for both oxygen and electric steelmaking-type slags.

Visualization of Slag Data for Efficient Monitoring and Improvement of Steelmaking Slag Operation in Electric Arc Furnaces, with a Focus on MgO Saturation

“…Slag formers such as lime, dolomitic lime, or doloma are charged with steel scrap alternative ferrous raw materials such as DRI in order to dissolve the oxidation produ and residues of the steel scrap, including SiO2, Al2O3, Cr2O3, P2O5 (e.g., [6]), and TiO2. Fe is partially reduced in the slag layer by mixing with carbon-containing steel melt or injecting coal or carbon fines (e.g., [7]).…”

“…e.g., [6]), and TiO 2 . FeO is partially reduced in the slag layer by mixing with carbon-containing steel melt or by injecting coal or carbon fines (e.g., [7]).…”

Refining and Casting of Steel

“…The papers covered by this Special Issue are state-of-the-art in the fields of crucial multiphase interactions in the steel making furnaces: basic oxygen furnace (BOF) [1] and electric arc furnace (EAF) [2]. Next, the research focuses on the matters related to the secondary refining processes; fluid's turbulences with nearby metal-slag interface in the ladles [3], the evolution of inclusions for Ti-bearing steels treated by calcium [4], and an influence of aluminum on flux flow in the ladle during Ruhrstahl Heraeus (RH) degassing operations [5].…”

“…Assis et al [2] investigated phosphorus equilibria between molten Fe-P alloys and CaO-SiO 2 -Al 2 O 3 -P 2 O 5 -FeO-MgO saturated slags based on the trend of using up to 100% direct reduced iron (DRI) in the batch. The results indicate that there is a significant decrease in the phosphorus partition coefficient (LP) as alumina in the slag increases.…”

“…Finally, an equilibrium correlation for phosphorus partition as a function of slag composition and temperature has been developed. It includes the effect of alumina and silica and is suitable for both oxygen and electric steelmaking-type slags [2].…”