Melting and refining with the basic lined EAF

The alkaline MgO based lining of this EAF makes it possible to refine the metal in the furnace itself Therefore it is possible to charge the fixmace with virtually any combination of scrap and foundry returns. The basic lining practice is used when the purchased scrap contains higher phosphoras and/or sulphur levels than desirable. 

Dephosphorisation of ihe melt is performed by periodic additions of lime during meltdown. Upon the injection of oxygen in the bath, phosphorous oxide is formed and trapped in the slag, together with other metallic oxides and impurities. The lime keeps the slag very basic, which stabilises the phosphorous oxide. At the same time carbon is burnt out. After sufficient reaction time, the oxygen injection is stopped and the slag is fully removed. 

After refining the metal composition is controlled and adjusted if necessary. Finally the metal is deoxidised by the addition of aluminium or other agents in the metal bath prior to tapping, to prevent the formation of CO bubbles during solidification. Further metal treatment, using an AOD or VODC converter (see Section 2.4.9 and 2.4.10) may be applied if the final alloy composition requires it. 

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