In a basic oxygen furnace, what does the term "basic" refer to?

In the context of a basic oxygen furnace, the term "basic" primarily refers to the chemical nature of the refractory lining of the furnace. This lining is made from basic materials, such as lime (calcium oxide) and magnesia (magnesium oxide), which are designed to withstand the high temperatures and chemical reactions occurring during the steelmaking process. The basic nature of the lining helps to protect the furnace structure and provides a favorable environment for removing impurities from the molten iron by promoting the formation of slag.

The basic lining is essential for controlling the acidity of the slag compared to that found in acidic furnaces. This aspect of the furnace's design enhances the effectiveness of the refining process, allowing for better control over the composition of the final steel product.