How is steel refined in a basic oxygen steel-making furnace?

• A. Through oxidation process, steel is refined
• B. By reducing with carbon monoxide
• C. By adding nitrogen to alloy
• D. By annealing at high temperature

Answer: (A)

In a basic oxygen furnace, refinement happens mainly through oxidation. Oxygen is blown into the molten iron, and it reacts with carbon and other impurities to form oxides. These oxides join with slag and are removed, lowering the carbon content and cleansing silicon, manganese, phosphorus, and sulfur to produce the desired steel composition. This decarburization by oxidation is what defines the BOF process. The other ideas don’t fit because reducing with carbon monoxide is a feature of blast furnace operations, adding nitrogen isn’t the refining mechanism used in this furnace, and annealing is a separate heat-treatment step after refining.