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US 6,383,251 B1Granted
Direct iron and steelmaking
OwnerWilliam Lyon Sherwoodinventor
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OwnerWilliam Lyon Sherwoodinventor
Estimating the term…
Solid state iron oxide reduction in a gas-solid reduction zone is combined with continuous melting of the hot solid reduced iron in a fuel-fired gas-solid-liquid melting zone within a rotary furnace by pneumatic transfer of the hot reduced iron by carrier gases through a transfer duct connected into an injection lance projecting into the melting zone and carrying a nozzle which directs a jet of hot reduced iron downwards into the metal bath, with a preferred embodiment of continually traversing the lance and thereby the jet of carrier gases and hot reduced iron longitudinally forwards and backwards enhancing heat transfer. The invention embraces a broad range of known solid-state reduction processes, classified either as: Group A. those employing gases within a gravity contact-supported or fluidized moving bed at substantial pressures of 1-5 atmospheres; or Group B. solid carbonaceous reductants in a rotary kiln or rotary hearth conducted at near ambient atmospheric pressure. A preferred embodiment applied to Group A reduction includes in situ reforming of a major portion of the hydrocarbons applied as reducing gases in the reduction zone, in combination with reforming a minor portion by partial oxidation with oxygen. The process provides for a high degree of in-process post-combustion with oxygen in the melting zone and various other preferred features to improve energy requirements, production rates, yields, costs and control of the liquid iron and steel product composition and quality in relation to the prior art.
A process for direct iron steelmaking which comprises heating and reducing iron oxides containing pieces in a gas-solid reduction zone within a reduction reactor yielding hot solid reduced iron pieces, and advancing said reduced iron pieces into a gas-solid-liquid melting zone containing a partially melted metal bath carried within the inner side walls of an elongate rotary furnace having at least a partial top cover of floating slag and fired by combustible and oxygen-containing gases generating a gas stream of hot furnace gases passing above the bath surface supplying heat for continually melting said hot reduced iron to yield liquid iron and steel, said gas stream exiting through an annular end opening of said furnace, including the following steps, in combination:
A process for direct iron and steelmaking which comprises heating and reducing iron oxides containing pieces in a gas-solid reduction zone within a reduction reactor yielding hot solid reduced iron pieces, and advancing said reduced iron pieces into a gas-solid-liquid melting zone containing a partially melted metal bath carried within the inner side walls of an elongate rotary furnace having at least a partial top cover of floating slag and fired by combustible and oxygen-containing gases generating a gas stream of hot furnace gases passing above the bath surface supplying heat for continually melting said hot reduced iron to yield liquid iron and steel, said gas stream exiting through an annular end opening of said furnace, including the following steps, in combination:
A process for direct iron and steelmaking which comprises heating and reducing iron oxides containing pieces in a gas-solid reduction zone within a reduction reactor yielding hot solid reduced iron pieces, and advancing said reduced iron pieces into a gas-solid-liquid melting zone containing a partially melted metal bath carried within the inner side walls of an elongate rotary furnace having at least a partial top cover of floating slag and fired by combustible and oxygen-containing gases generating a gas stream of hot furnace gases passing above the bath surface supplying heat for continually melting said hot reduced iron to yield liquid iron and steel, said gas stream exiting through an annular end opening of said furnace, including the following steps, in combination:
A process for direct iron and steelmaking which comprises heating and reducing iron oxides containing pieces in a gas-solid reduction zone within a reduction reactor yielding hot solid reduced iron pieces, and advancing said reduced iron pieces into a gas-solid-liquid melting zone containing a partially melted metal bath carried within the inner side walls of an elongate rotary furnace having at least a partial top cover of floating slag and fired by combustible and oxygen-containing gases generating a gas stream of hot furnace gases passing above the bath surface supplying heat for continually melting said hot reduced iron to yield liquid iron and steel, said gas stream exiting through an annular end opening of said furnace, including the following steps, in combination:
A process according to claimed 1, 2, 3, 4 or 5 including introducing pieces of materials selected from the group comprising fluxes, alloys and carburizing agents into said transfer duct which are also propelled by said carrier gases and injected into said partially melted metal bath along with said hot reduced iron pieces.
Dependencies are inferred from the claim text.