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US3853538A Expired / Lapsed US ⏱️ 0.0 years remaining

Use of reducing gas by coal gasification for direct iron ore reduction

Assignee: United States Steel Corp
•
Filing: 1973-07-20
•
Granted: 1974-12-10
•
Expires: 1993-07-20
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Abstract

Abstract A method employing reducing gas in an ore reducing furnace, which reducing gas is obtained from the gasification of coal is disclosed in which part of the unused reducing components from the reducing furnace is recirculated, and its CO2 content reduced, and in which the composition of the original gas coming from the coal gasification process is enriched while mixing it with the recycled gas. A portion of the recycled gas containing a very small concentration of oxidizing components can be introduced into the gasifier to control the gasification temperature, or all or a portion may be introduced at a point intermediate between the gasifier and desulphurizer to bring the gas to a suitable temperature for desulphurization, or a portion can be introduced to a cooling zone in the shaft furnace to cool the reduced ore; in all cases, the recycled gas enriches the coal gas and helps to bring it to a suitable temperature for ore reduction.

Inventors

  • 👤 E Nemeth

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-01 08:45
CPC Classifications
C; C21; C21B; C21B13/00; C21B13/0073; C21B13/02; C21B13/029; C21B2100/00; C21B2100/20; C21B2100/28; C21B2100/282; C21B2100/40; C21B2100/42; C21B2100/60; C21B2100/64; Y; Y02; Y02P; Y02P10/00; Y02P10/10; Y02P10/122; Y02P10/134; Y02P10/20

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 97 words
PROCESS FOR REDUCING IRON ORE COMPRISING: A. GASIFYING SOLID FOSSIL FUEL AT A TEMPERATURE OF AT LEAST 2,000*F TO OBTAIN A REDUCING GAS CONTAINING AT LEAST ABOUT 80 PERCENT HYDROGEN AND CARBON MONOXIDE, AND A MOLTEN SLAGE. B. MIXING AND REDUCING GAS WITH A CO2-LEAN TAIL GAS FROM A REDUCING FURNACE IN A VOLUME RATIO OF FROM 40:60 TO 60:40 TO REDUCE THE TEMPERATURE OF THE MIXTURE TO LESS THAN 2,000*F, C. REMOVING SULFUR COMPOUNDS FROM THE MIXTURE THUS OBTAINED, D. PASSING THE DESULFURIZED MIXTURE THUS OBTAINED INTO A REDUCING FURNACE FOR THE REDUCTION OF IRON OXIDE,
Claim 2
Dependent Claim 97 words
PROCESS FOR REDUCING IRON ORE COMPRISING: A. GASIFYING SOLID FOSSIL FUEL AT A TEMPERATURE OF AT LEAST 2,000*F TO OBTAIN A REDUCING GAS CONTAINING AT LEAST ABOUT 80 PERCENT HYDROGEN AND CARBON MONOXIDE, AND A MOLTEN SLAGE. B. MIXING AND REDUCING GAS WITH A CO2-LEAN TAIL GAS FROM A REDUCING FURNACE IN A VOLUME RATIO OF FROM 40:60 TO 60:40 TO REDUCE THE TEMPERATURE OF THE MIXTURE TO LESS THAN 2,000*F, C. REMOVING SULFUR COMPOUNDS FROM THE MIXTURE THUS OBTAINED, D. PASSING THE DESULFURIZED MIXTURE THUS OBTAINED INTO A REDUCING FURNACE FOR THE REDUCTION OF IRON OXIDE,
Claim 3
Dependent Claim 20 words
Process of claim 1 in which the reducing gas - tail gas mixture is desulfurized by calcined dolomite or limestone.
Claim 4
Dependent Claim 23 words
Process of claim 1 in which a portion of the CO2-lean recycle gas is passed to the cooling zone of the reducing furnace.
Claim 5
Dependent Claim 27 words
Process of claim 1 in which at least a portion of the CO2-lean tail gas is mixed with the reducing gas in the solid fossil fuel gasifier.
Claim 6
Dependent Claim 12 words
Process of claim 1 in which the solid fossil fuel is coal.
Claim 7
Dependent Claim 20 words
Process of claim 1 in which over 90 percent of the gas delivered to the reducing furnace is reducing gas.
Claim 8
Dependent Claim 23 words
Process of claim 1 in which the mixture of reducing gas and recycled CO2-lean tail gas has a temperature of at least 1,200*.

References Cited (Backward Citations)

US1256623A Cited
US2740706A Cited
US2755179A Cited
US3562780A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1977-12-09 1978-06-10 1978-12-10 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1981-12-09 1982-06-10 1982-12-10 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1985-12-09 1986-06-10 1986-12-10 $7700.00 Window Closed / Lapsed

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