Patent US3663202A successfully refreshed from Google Patents.
US3663202A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for manufacture of pig iron or steel
Assignee: BK Giulini Chemie GmbH
•
Filing: 1969-11-25
•
Granted: 1972-05-16
•
Expires: 1989-11-25
Abstract
Abstract A two-stage method for the reduction of iron-oxide-containing raw materials wherein the iron oxide is reduced by means of solid carbonaceous material in a first stage carried out in a rotary kiln. The raw materials issue from the kiln in the form of a partially reduced sinter containing at least 5 percent free carbon. Reduction is completed in a second state carried out in a direct-fired smelting furnace, where a part of the free carbon in the sinter is burned by hot, oxygen-containing exhaust gases of the direct-fired smelting furnace to effect a temperature rise to smelt the sinter from the first stage.
Inventors
- 👤 Hermann Ruter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 13:01
CPC Classifications
C; C21; C21B; C21B13/00; C21B13/14; C21B11/00; C21B11/10; Y; Y02; Y02P; Y02P10/00; Y02P10/10; Y02P10/134
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
34 words
The method as claimed in claim 1, the step of producing including the passing of a mixture of said material with solid carbonaceous material through a rotary kiln operated at 900* to 1,100* C.
Claim 2
Dependent Claim
21 words
The method as claimed in claim 1, the zero-valent iron in the sinter amounting to 80-92 percent of the total iron.
Claim 3
Dependent Claim
20 words
The method as claimed in claim 1, the solid carbonaceous material in the sinter amounting to 8 to 12 percent.
Claim 4
Dependent Claim
21 words
The method as claimed in claim 1, said exhaust gas having an oxygen content of 5 to 10 percent by volume.
Claim 5
Dependent Claim
18 words
The method as claimed in claim 1, said exhaust gas having a temperature of at least 1,400* C.
Claim 6
Dependent Claim
45 words
The method as claimed in claim 2, the step of impinging including the steps of allowing said sinter issuing from said kiln to fall onto the hearth of a stationary smelting furnace and directing flames producing said exhaust gas at the sinter on the hearth.
Claim 7
Dependent Claim
26 words
The method as claimed in claim 2, the step of producing further including a contacting of said mixture while in the kiln with a reducing gas.
Claim 8
Dependent Claim
24 words
The method as claimed in claim 1, wherein said material in the sinter is in the particle size range of 0 to 2 millimeters.
Claim 9
Dependent Claim
14 words
The method as claimed in claim 1, wherein said iron-oxide-containing material is red mud.
References Cited (Backward Citations)
US1871848A
Cited
US2526658A
Cited
US2526659A
Cited
US2806779A
Cited
US3153588A
Cited
US3205065A
Cited
US3295958A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-16 | 1975-11-15 | 1976-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-16 | 1979-11-15 | 1980-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-16 | 1983-11-15 | 1984-05-16 | $7700.00 | Window Closed / Lapsed |