Process and apparatus for the manufacture of steel

A steelmaking method comprising providing a first enclosed, elongated melting and decarburization reactor and a second elongated, enclosed final refining reactor, providing a bath of liquid iron-carbon alloy in the first reactor, providing a foamy slag layer overlying the liquid iron-carbon alloy bath, introducing a preheated particulate iron-base charge containing carbon into the liquid iron-carbon alloy bath, injecting oxygen into the liquid iron-carbon alloy bath thereby decarburizing the bath and forming carbon monoxide and an liquid intermediate iron-carbon alloy having a carbon content higher than a desired final carbon content, injecting oxygen into the liquid iron-carbon alloy in the second reactor thereby decarburizing the alloy and forming carbon monoxide, substantially excluding other sources of oxygen from entry into the second reactor, collecting the carbon monoxide generated in the second reactor, introducing into the first reactor additional carbon monoxide from the second reactor, burning substantially all of the carbon monoxide in the foamy slag in the first reactor with oxygen injected into the foamy slag, continuing the reaction in the first reactor in a well-mixed mode and essentially autogeneously until the carbon content of the liquid iron-carbon alloy in the first reactor reaches a desired level for introduction of the liquid iron-carbon alloy into the second reactor, deslagging the liquid iron-carbon alloy in the first reactor, and introducing the deslagged liquid iron-carbon alloy into the second reactor.

A process for converting an iron-base charge material containing carbon to a desired final steel having a carbon content of about 0.01% to about 0.5% carbon, comprising providing a first, elongated reactor and a second, elongated reactor, providing a liquid iron-carbon bath in the first reactor, introducing particulate iron-containing material under the surface of the liquid metal bath in the first reactor, agitating the liquid metal bath in the first reactor to a well-mixed condition by injecting oxygen into the bath through a plurality of locations spaced apart along the length and width of the first reactor and evolving carbon oxides from the metal bath by the reaction of carbon and oxygen, continuing the introduction of particulate iron-containing material and oxygen injection in the first reactor to provide a steady state reaction condition with the metal bath containing an intermediate carbon level of about 0.5% to about 2%, transferring liquid intermediate iron-carbon alloy to the second reactor, injecting oxygen into the metal bath in the second reactor through a plurality of locations spaced apart along the length of the second reactor in a manner to provide an essentially plug-type flow with a carbon gradient along the length of the reactor from the carbon content of the intermediated iron carbon alloy at a liquid metal entry end to the desired final steel carbon content at a liquid metal exit end of the second reactor, autogeneously refining the liquid intermediate iron-carbon alloy to the desired final steel carbon content, collecting carbon monoxide gas evolved in the second reactor and burning it with oxygen in the first reactor.

A facility for the production of steel from an iron-based charge material containing carbon, comprising:

• a first refractory-lined melting and decarburization reactor;
• means to provide a liquid iron-carbon bath and a foamy slag layer in the first reactor;
• means to introduce particulate charge material as feed into the first reactor;
• means to inject oxygen into the liquid iron-carbon bath at a plurality of locations in the first reactor;
• means to inject post-combustion oxygen above the surface of the liquid iron-carbon bath at a plurality of locations in the first reactor;
• means to inject and burn carbon monoxide with oxygen above the liquid iron-carbon bath in the first reactor;
• means to collect carbon dioxide-rich off-gas produced by the burning of carbon monoxide gas in the first reactor, and to use the sensible heat in such off-gas to preheat the charge material feed;
• means to collect dust emitted from the liquid iron-carbon bath in the first reactor and to return the dust to the first reactor;
• a separate elongated, second, refractory-lined refining reactor adapted to receive liquid iron-carbon alloy produced in the first reactor;
• means to inject oxygen into the liquid iron-carbon alloy at spaced-apart positions along the length of the second reactor;
• means to collect and cool carbon monoxide gas generated in the second reactor and to transfer it to the first reactor to be burned with oxygen therein, and
• means to collect a final liquid steel product produced in the second reactor.

A process for producing steel from an iron-base charge material containing carbon comprising:

• a. providing a first reactor containing an iron-base molten metal bath;
• b. introducing carbon to the molten bath by feeding the carbon-containing charge material to the bath;
• c. introducing oxygen to the molten metal bath at a rate stoichiometrically related to the rate at which carbon is introduced so as to remove carbon from the bath at essentially the same rate at which carbon is introduced thereto;
• and
• d. feeding the resulting iron-carbon alloy to a separate second oxygen-refining reactor and in the second reactor refining the iron-carbon alloy to steel.