Oxygen lance

Fig. 4. Sketch of a basic-oxygen steelmaking furnace, where an oxygen lance is iaserted through the mouth of the furnace (1).

Basic oxygen furnaces (BOFs) have largely replaced open hearth furnaces for steelmaking. A water-cooled oxygen lance is used to blow high-purity oxygen into the molten metal bath. This causes violent agitation and rapid oxidation of the carbon, impurities, and some of the iron. The reaction is exothermic, and an entire heat cycle requires only 30-50 min. The atmospheric emissions from the BOF process are listed in Table 30-16. 

The second term indicates that by increasing the melt temperature, e.g., by oxygen lancing, to 1850 °C, AG° for the reaction becomes more positive and the reverse reaction leading to retention of chromium in steel becomes favorable. Addition of a deoxidant, e.g., silicon as ferrosilicon, which forms an oxide stabler than Cr203, also leads to further recovery of chromium in steel ... 

The danger of burns from faulty connections on oxygen lances is eliminated... 

Because of these major advantages, it is expected that Jet Tappers will eventually replace the oxygen lance method of tapping entirely. 

OLP [Oxygene Lance Poudre] A steelmaking process in which powdered lime is blown into the furnace through the oxygen stream in order to combine with the phosphorus. Developed in the late 1950s by rinstitut des Recherches de la Siderurgie. See also LD/AC. 

The recuperative melter is amenable to supplemental oxy/fuel technique or the premixed oxygen enrichment technique (see Chapter 1). Oxygen lancing is typically not used. In the supplemental oxy/fuel technique, an air/fuel burner is simply replaced by an oxy/fuel burner. When premix is applied, oxygen injection into the air main typically occurs downstream of the recuperator to avoid problems associated with air leaks in the recuperator. Care should be taken in locating the oxygen diffuser as discussed in Chapter 10. 

As an indication of the flexibility of the EAF, it is used in some developing countries for the direct reduction of iron ore by carbon [27.18]. The furnace is charged with iron ore intimately mixed with ground carbon. Quicklime, calcined dolomite and fluorspar are added and an oxygen lance is used to oxidise the impurities much as in the BOS process. The slag is removed and the chemical... 

The OENR tests were done with an under-port oxygen lancing configuration (see Figure 9). The oxygen lances were placed under the exhaust port on the opposite side of the flame with an upward angle. 

Example D Recycling of Contaminated Scrap (Oxygen Lancing)... 

Oxygen lancing improves the combustion efficiency of air-fuel systems and reduces atmospheric emissions. This technology injects oxygen primarily to bum off feedstock contamination (e.g. oil, paint, organics, hydrocarbons). 

Fig. 2.37 Oxygen lances convert feedstock combustibles into energy.

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