MgO-saturated slag is a prerequisite in both EAF and BOF steelmaking. MgO saturation limit, depends mainly on FeO content, basicity, and temperature, and varies from 8% to 12%, depending on each steel plant’s operational parameters. If that content is lower, slag has lower viscosity and can dissolve MgO from the bricks of the working lining, resulting in decrease of the expected bricks’ lifetime. Partial replacement of lime addition (e.g., 20%) with calcined magnesium oxide (10-40mm), can keep the slag’s MgO content at the required high levels.
Magnesium oxide is the best source of MgO since it is much more reactive than other MgO recycled refractories. It has more than double MgO content than the dolomitic lime and reduces the raw material requirements along with the slag volume.
With the addition of MgO, the slag chemistry is properly controlled, simultaneously achieving:
- less fettling consumption.
- less gunning consumption.
- more work lining brick life.
- less electric consumption.
- productivity increase.