Method for the reduction of a slag having a high degree of chromium in an electric arc furnace

US8043401B2 · kind B2 · utility

Assignee

• SMS SIEMAG AG · DE

Inventors

• Johann Reichel · Mülheim an der Ruhr, DE
• Lutz Rose · Goldkronach, DE

Key dates

• Filing date: Jan 10, 2008
• Grant date: Oct 25, 2011
• Expiry date: Jan 10, 2028

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P10/20
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

During the production of stainless steel, a slag is formed during the melting of the solid material in the electric arc furnace, the slag having a high degree of metal oxides, particularly chromium oxide. The chromium concentration often reaches values of more than 30%. Currently, such slags cannot be reduced to a desired degree due to their composition. In order to minimize the resulting high loss of recyclable material, the invention provides to charge the electric arc furnace with pellets, or briquettes (8), which are made of a defined mixture of an iron carrier as the ballast material, carbon, or carbon and silicon, as the reducing agent, and a binder, wherein they react beneath the slag layer (7) in the steel melt (6) with the metal oxides of the slag (7), particularly with the chromium oxide present, in a floating, chemical, and reducing manner. The reaction gases (12) produced in the process, which are mainly made of carbon monoxide, advantageously support a foaming of the slag (7).