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Why does basic oxygen steelmaking use pure oxygen rather than air?
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iron processing
Iron ore is one of the most abundant elements on Earth, and one of its primary uses is in the production of steel. When combined with carbon, iron changes character completely and becomes the alloy steel.
The basic oxygen process utilizes pure oxygen rather than air for several critical technical and commercial reasons:
- Increased Efficiency and Speed: Using pure oxygen at high flow rates enables the rapid oxidation of elements such as carbon, silicon, and phosphorus. This allows for significantly faster production times, with a full charge often refined in approximately 20 minutes.12
- Elimination of Nitrogen Cooling: Air is composed largely of nitrogen, which acts as a heat sink. By using pure oxygen, this cooling effect is removed, allowing the excess heat generated by the exothermic refining reactions to be used to melt a larger proportion of scrap metal added to the charge.3
- Improved Steel Quality: Nitrogen can be absorbed by liquid steel, where it significantly decreases the metal's ductility. Using pure oxygen instead of air results in steel with a lower nitrogen content, leading to a higher-quality final product.24