REVAN™
There is an old saying in steel making “Take care of the slag and it will take care of the metal”. Slags are an important part of making quality steel. They remove unwanted oxides, sulfides, nitrides and phosphides. They provide a cover to protect refined steel from reoxidation and nitrogen and hydrogen pickup. Slags are also the basis for effective calcium treatment to improve castability and yields for continuous casters. However, slag compositions must be closely controlled or else they will cause additional problems and become liabilities. Improper slag compositions can lead to harmful reversion of S, P, Si, and various oxide inclusions. If the slag liquidus is above the casting or teeming temperatures, they may require excess energy to flux and stabilize to a more liquid phase. In addition, there is the possibility of removing desired elements in the steel such as Al, Si, Ti, Mn, V, Nb, Cr, etc.
Synthetic slags are a valuable and necessary tool for today’s steelmakers. By understanding melt dynamics and engineering synthetic slags to shift ladle slags into the beneficial region of the CaO – Al2O3 – SiO2 systems, steelmakers derive the benefits of material and energy savings, fluid slags throughout the steelmaking process, good sulfur and inclusion removal, improved castability and overall yields, an increased refractory life. Steelmaking processes that do not generate Al2O3 can also utilize synthetic slags to generate the same benefits.