Electric arc furnace having slag door and post combustion process

A method of operating an electric arc furnace comprising the steps of:

• melting scrap in a melting vessel by placing scrap through a shaft opening of a scrap receiving shaft positioned on the roof of the melting vessel;
• generating an electric arc to the scrap through at least one electrode extending through the roof of the vessel to form a molten metal bath;
• extending an oxygen lance through a slag discharge opening and into the melting vessel into a slag free area formed by an arcuate configured water-cooled panel positioned above the slag door and injecting oxygen into the molten metal bath to create a reaction where carbon monoxide is generated;
• exhausting gas produced from the oxygen injecting step from the melting vessel;
• measuring the carbon monoxide concentration in the exhausted gas;
• and
• injecting post combustion oxygen into the melting vessel in an amount sufficient to provide post combustion based on the measured concentration of the carbon monoxide in the exhausted gas.

An electric arc furnace comprising:

• a melting vessel having a top opening;
• a roof positioned over the top opening and including a shaft opening for permitting charging of metal into the melting vessel;
• at least one electrode extending through the roof into melting vessel for generating an electric arc and forming a molten metal bath;
• a slag door portion defining a slag discharge opening through which slag is discharged from the melting vessel;
• at least one oxygen lance that is extended through the slag door portion into the melting vessel for injecting oxygen into the molten metal bath to create a reaction where carbon monoxide gas is generated;
• means for exhausting gas from the melting vessel;
• means for measuring the carbon monoxide gas concentration of the exhausted gas;
• means for injecting post combustion oxygen into the melting vessel in an amount sufficient to provide post combustion based on the measured concentration of the carbon monoxide exhausted gas, a post combustion chamber for receiving the exhausted gas, and further comprising means for injecting post combustion oxygen into the post combustion chamber, wherein the amount of post combustion oxygen injected into the post combustion chamber is determinative of the post combustion oxygen injected into the melting vessel;
• and
• a plurality of water-cooled oxygen injectors through which post combustion oxygen is injected, wherein each of said water-cooled oxygen injectors comprise a substantially rectangular configured housing having an oxygen chamber, means for passing oxygen into said oxygen chamber, a plurality of oxygen orifices through which oxygen passes outward from said oxygen chamber, and a water cooling chamber surrounding said oxygen chamber and defined by the oxygen chamber and the substantially rectangular housing.