Interfacial Reactions between Slag and Melt in the New World of High Manganese Steels

Abstract

At Department of Ferrous Metallurgy of the RWTH Aachen University in Germany steels in the system Fe-Mn-C(-Al) are investigated and produced in the framework of the SFB 761 "steel-ab initio". A new world of steel grades leads to special challenges regarding the production and recycling at the end-of-life cycle of product. In order to recycle high manganese steel alloys the EAF has to be chosen preferentially. A good slag practice is necessary avoiding loss of manganese content during melting in the EAF. This paper investigates on the reaction kinetics at the interface of slag and steel containing Mn (17-22 wt.-%) and up to 3 wt.-% Al. The effect of changes in the composition of slag and steel on the interfacial reaction kinetics is studied. The thermodynamic software FactSage TM is utilized to calculate the composition of slag and steel at equilibrium.

Effect of Mn Content on the Reaction between Fe-xMn (x = 5, 10, 15, and 20 Mass pct) Steel and CaO-SiO2-Al2O3-MgO Slag

“…So, all these results give strong evidence that the content of dissolved oxygen in this study is in equilibrium with Mn content in molten steel, although other metal elements, such as Si and Al, also participate in the reactions. That is, the dissolved oxygen content is controlled by Reaction (9).…”

“…The MnO content in slag is much higher than that in equilibrium with conventional steel because of the reaction between [Mn] in steel and SiO 2 in slag. Peymandar [9] studied the reaction between CaO-SiO 2 -Al 2 O 3 -MgO slag (initial slag basicity = 1.3, Al 2 O 3 =15 mass pct) and high-Mn steel, with a focus on reaction kinetics. Deng [10] studied the reaction between Al-killed manganese steel and CaO-SiO 2 -Al 2 O 3 -MgO ladle slag.…”