US4425659A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Metal oxide reduction furnace
Assignee: ABB Norden Holding AB
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Filing: 1981-08-18
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Granted: 1984-01-10
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Expires: 2001-08-18
Abstract
Abstract A metal oxide reduction furnace has a shaft holding a verticle column of coke. An electric arc on the side of the lower portion of the column burns a cavity in the coke column and the arc is surrounded by the side wall and inner closed end of the cavity so that high temperatures are obtained. A stream of the metal oxide in particulated form mixed with a reducing agent is projected into the cavity to react endothermically within the cavity and lower the high temperature while reducing the oxide to its metal.
Inventors
- 👤 Sven-Einar Stenkvist
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 15:42
CPC Classifications
C; C21; C21B; C21B5/00; C21B5/001; C21B5/002; C21B13/00; C21B13/12; Y; Y02; Y02P; Y02P10/00; Y02P10/10; Y02P10/134
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
220 words
A metal oxide reduction furnace having a hearth, a shaft extending upwardly from the hearth and adapted to contain a coke column above the hearth, contact means for connecting electric power to the coke column, an electric arcing electrode extending transversely through a side of the shaft and adapted to be connected with the power so as to form an arc with a side of the coke column and burn a cavity therein, said furnace being adapted to operate as a DC arc furnace and in which said contact means is an anode vertically offset from the arcing electrode so as to be controlled by the coke column and the arcing electrode is a cathode, the shaft's said side having a hole through which the arcing electrode extends and the hole forming an annular space around the electrode, feeding means for feeding into the cavity in particulate form the metal oxide to be reduced together with a reducing agent, said feeding means being an annular nozzle pointing through the annular space towards the arcing electrode's tip and surrounding the arcing electrode and adapted to be fed with the metal oxide and reducing agent carried by a pressurized gas flow so as to form an annular flow surrounding the arcing electrode's tip and the arc it forms with the coke column.
Claim 2
Dependent Claim
220 words
A metal oxide reduction furnace having a hearth, a shaft extending upwardly from the hearth and adapted to contain a coke column above the hearth, contact means for connecting electric power to the coke column, an electric arcing electrode extending transversely through a side of the shaft and adapted to be connected with the power so as to form an arc with a side of the coke column and burn a cavity therein, said furnace being adapted to operate as a DC arc furnace and in which said contact means is an anode vertically offset from the arcing electrode so as to be controlled by the coke column and the arcing electrode is a cathode, the shaft's said side having a hole through which the arcing electrode extends and the hole forming an annular space around the electrode, feeding means for feeding into the cavity in particulate form the metal oxide to be reduced together with a reducing agent, said feeding means being an annular nozzle pointing through the annular space towards the arcing electrode's tip and surrounding the arcing electrode and adapted to be fed with the metal oxide and reducing agent carried by a pressurized gas flow so as to form an annular flow surrounding the arcing electrode's tip and the arc it forms with the coke column.
Claim 3
Dependent Claim
26 words
The furnace of claim 1 in which the shaft and hearth form a pressure-containment and the shaft's top has a gas outlet above the coke column.
Claim 4
Dependent Claim
50 words
The furnace of claim 1 in which the anode is formed by a metal ring on the shaft's wall at a height above the arcing electrode to cause the portion of the coke column between the anode and arcing electrode to function as an arc flare shield for the anode.
Claim 5
Dependent Claim
32 words
The furnace of claim 1 in which an electromagnetic coil surrounds the shaft's said hole and is adapted to be electrically energized so as to provide a magnetic field surrounding the arc.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-01-09 | 1987-07-11 | 1988-01-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-01-09 | 1991-07-11 | 1992-01-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-01-09 | 1995-07-11 | 1996-01-10 | $7700.00 | Window Closed / Lapsed |