Blast furnace and method of operating the same

Claim 2

Method of reducing iron ores to form metallic iron comprising: a. preparing and introducing a charge of iron oxide-providing material, fluxing agents and coke into the top of a blast furnace having a tertiary zone, a secondary zone and a primary zone wherein combustion occurs; b. passing said charge downwardly through said furnace and through said tertiary zone that comprises a preheating and reducing area of constantly increasing temperature but of less than about 1000*C; c. introducing a controlled flow of a heated gaseous reducing agent into said zone to combine with reducing gases from the secondary and primary zones and to pass up through said zone and into intimate contact with said charge to effect a reduction of the major portion of the iron oxide of the charge and to form carbon oxide and a first mixture of metallic iron, iron oxide, slag, coke and residual charge; d. passing said first mixture downwardly through said furnace to said secondary zone comprising a bosh area, having a temperature of about 1000*C at the top, and having, in the lower portion thereof and adjacent to a primary zone, a consumable carbon grate constantly formed from Coke in said first mixture; e. passing hot combustion gases from said primary zone upwardly into said secondary zone to form molten metal and slag; f. introducing into said secondary zone a heated gaseous reducing agent which combines with the hot combustion gases to reduce their temperature and to assist in reducing additional iron oxide with the formation of carbon oxide; g. passing said molten materials downwardly through said carbon grate into a primary zone that comprises a hearth area in which combustion occurs and which is maintained at a still higher temperature than said secondary zone, injecting a mixture of air and oxygen as an oxidizing gas into said primary zone and bringing said gas into intimate contact with coke from the charge, the adiabatic flame temperature in said zone being at least about 1860*C, forming carbon oxide by combustion and passing said hot combustion gases upwardly through the blast furnace; and h. withdrawing said molten metallic iron and said molten slag from the base of the furnace.

Claim 3

Method of operating a blast furnace to form metallic iron comprising: a. charging into the top of said blast furnace a burden comprising iron ore, sinter, pellets or other material with a metallic content, limestone or other fluxes and coke; b. passing said burden downwardly through a preliminary preheating and reducing zone in said furnace of constantly increasing temperature; c. constantly controlling the temperature of the zone by selectively introducing adjacent the lower end of said zone a flow of a heated gaseous carbonaceous reducing agent and blending said agent with the stream of heated gas moving up through said zone, bringing said now blended stream into intimate contact with said burden and reacting said gaseous agent and said burden to preheat and reduce the major portion of said iron ore to form metallic iron and a gaseous product and a first solids mixture of metallic iron, coke, slag and residual charge without causing a solution loss and without premature melting of the burden materials; d. passing said first mixture further downwardly through a second zone in said furnace that comprises a bosh area, having in the lower portion thereof and adjacent said primary zone a consumable carbon grate constantly formed from coke in said first mixture; e. passing hot combustion gases from said primary zone upwardly into said secondary zone to form molten metal and slag; f. introducing into said secondary zone a heated carbonaceous reducing agent which combines with the hot combustion gases to reduce their temperature and to assist in reducing additional iron oxide; g. passing said molten materials downwardly through said carbon grate into a primary zone that comprises a hearth area in which combustion occurs and which is maintained at a still higher temperature than said secondary zone, injecting a mixture of air and oxygen as an oxidizing gas into said primary zone and bringing said gas into intimate contact with coke from the charge, the adiabatic flame temperature in said zone being at least about 1860*C, forming carbon oxide by combustion and passing said hot combustion gases upwardly through the blast furnace; h. separately recovering molten metallic iron and molten slag; and withdrawing exhaust gases containing CO2 and H2O from the top of said furnace.

Claim 4

Method of operating a blast furnace to form metallic iron comprising: a. charging into the top of said blast furnace a burden comprising iron ore, sinter, pellets or other material with a metallic content, limestone or other fluxes and coke; b. passing said burden downwardly through a preliminary preheating and reducing zone in said furnace of constantly increasing temperature; c. constantly controlling the temperature of the zone by selectively introducing adjacent the lower end of said zone a flow of a heated gaseous carbonaceous reducing agent and blending said agent with the stream of heated gas moving up through said zone, bringing said now blended stream into intimate contact with said burden and reacting said gaseous agent and said burden to preheat and reduce the major portion of said iron ore to form metallic iron and a gaseous product and a first solids mixture of metallic iron, coke, slag and residual charge without causing a solution loss and without premature melting of the burden materials; d. passing said first mixture further downwardly through a second zone in said furnace that comprises a bosh area, having in the lower portion thereof and adjacent said primary zone a consumable carbon grate constantly formed from coke in said first mixture; e. passing hot combustion gases from said primary zone upwardly into said secondary zone to form molten metal and slag; f. introducing into said secondary zone a heated carbonaceous reducing agent which combines with the hot combustion gases to reduce their temperature and to assist in reducing additional iron oxide; g. passing said molten materials downwardly through said carbon grate into a primary zone that comprises a hearth area in which combustion occurs and which is maintained at a still higher temperature than said secondary zone, injecting a mixture of air and oxygen as an oxidizing gas into said primary zone and bringing said gas into intimate contact with coke from the charge, the adiabatic flame temperature in said zone being at least about 1860*C, forming carbon oxide by combustion and passing said hot combustion gases upwardly through the blast furnace; h. separately recovering molten metallic iron and molten slag; and withdrawing exhaust gases containing CO2 and H2O from the top of said furnace.

Claim 5

A method as set forth in claim 2 wherein the temperature in said preliminary reducing and preheating zone is controlled to avoid solution loss and premature melting and does not exceed 1000*C., the temperature in said bosh area is at least 1000*C., and there is developed in said primary zone an adiabatic flame temperature of at least 1860*C.

Claim 6

A method as set forth in claim 2 wherein there are developed adiabatic flame temperatures of at least 1860*C. in said primary zone.

Claim 7

A method as set forth in claim 2 wherein said oxidizing gas in Oxygen-enriched air containing at least about 25 percent added oxygen.

Claim 8

A method as set forth in claim 2 wherein said gaseous reducing agent consists essentially of an admixture of CO and H2.

Claim 9

A method as set forth in claim 2 wherein a portion of said gases withdrawn from the top of said furnace are reacted with a carbonaceous reducing agent to re-form carbon monoxide and hydrogen and said re-formed gases are recycled to said zones as said gaseous reducing agent.

Claim 12

The system as in claim 8 wherein separate means are provided for each of said secondary and said tertiary sets of tuyeres for introducing gaseous reducing agents thereinto separately.

Claim 13

A system as in claim 8 wherein said secondary set of tuyeres is disposed adjacent the top of said bosh zone and below the mantel.

Claim 14

A system as in claim 8 wherein said converter has a plurality of gas tuyeres and includes means to conduct said top gases to said gas converter and through each gas converter tuyere.

Claim 15

A system as in claim 8 including means to conduct gases from said gas converter to each tuyere of said secondary and said tertiary sets of tuyeres.

Claim 16

A system as set forth in claim 8, including means for supplying CO and other basic oxygen steel furnace gas constituents to said gas converter.

Claim 17

A system as set forth in claim 8 wherein said last mentioned means comprises a basic oxygen steel furnace.

Claim 18

A system as set forth in claim 8 wherein said gas converter comprises a blast furnace-like device.