US3929456A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Carbothermic production of aluminum
Assignee: Reynolds Metals Co
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Filing: 1973-10-17
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Granted: 1975-12-30
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Expires: 1993-10-17
Abstract
Abstract A carbothermic process for the production of aluminum metal contaminated with no more than about 5 weight percent of aluminum carbide in a single furnace operation which comprises contacting a feed comprising an oxide of aluminum and a carbon-containing compound such as aluminum carbide in an open arc furnace wherein heat is applied via an open arc in a manner such that only the surface of the charge is raised to reaction temperature and the aluminum which is formed in the condensed state is then allowed to flow at a temperature sufficiently low to prevent substantial contamination with aluminum carbide.
Inventors
- 👤 Robert M Kibby
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:06
CPC Classifications
C; C22; C22B; C22B21/00; C22B21/02
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
158 words
A CARBOTHERMIC PROCESS FOR THE PRODUCTION OF ALUMINUM FROM AN ALUMINUM OXIDE WHICH COMPRISES: A. STRIKING AN OPEN ELECTRICAL ARC TO A PORTION OF THE SURFACE OF A CHARGE COMPRISING AN ALUMINUM OXIDE AND AT LEAST ONE MATERIAL SELECTED FROM THE GROUP CONSISTING OF CARBON, ALUMINUM COMPOUNDS CONTAINING CARBON, AND MIXTURES THEREOF; B. LIMITING THE HEATING EFFECT OF THE ARC BY CONTROLLING THE TIME THE ARC IS STRUCK TO ANY GIVEN PORTION OF THE SURFACE OF SAID CHARGE SO THAT THE ALUMINUM FORMED BY THE REACTION OF THE CHARGE U IS MAINTAINED SUBSTANTIALLY IN THE LIQUID STATE WITH THE PROVISO THAT ONLY A SMALL PORTION OF THE CHARGE IN THE REACTION ZONE IS HEATED TO REACTION TEMPERATURE WHILE THE MAJORITY OF THE CHARGE IN THE REACTION ZONE IS NOT AT REACTION TEMPERATURE AT ANY GIVEN TIME; AND C. CAUSING THE LIQUID AKUMINUM FORMED UNDER THE ARC TO FLOW AWAY FROM THE ARC AND OVER THE NON-REACTED PORTION OF
Claim 2
Dependent Claim
158 words
A CARBOTHERMIC PROCESS FOR THE PRODUCTION OF ALUMINUM FROM AN ALUMINUM OXIDE WHICH COMPRISES: A. STRIKING AN OPEN ELECTRICAL ARC TO A PORTION OF THE SURFACE OF A CHARGE COMPRISING AN ALUMINUM OXIDE AND AT LEAST ONE MATERIAL SELECTED FROM THE GROUP CONSISTING OF CARBON, ALUMINUM COMPOUNDS CONTAINING CARBON, AND MIXTURES THEREOF; B. LIMITING THE HEATING EFFECT OF THE ARC BY CONTROLLING THE TIME THE ARC IS STRUCK TO ANY GIVEN PORTION OF THE SURFACE OF SAID CHARGE SO THAT THE ALUMINUM FORMED BY THE REACTION OF THE CHARGE U IS MAINTAINED SUBSTANTIALLY IN THE LIQUID STATE WITH THE PROVISO THAT ONLY A SMALL PORTION OF THE CHARGE IN THE REACTION ZONE IS HEATED TO REACTION TEMPERATURE WHILE THE MAJORITY OF THE CHARGE IN THE REACTION ZONE IS NOT AT REACTION TEMPERATURE AT ANY GIVEN TIME; AND C. CAUSING THE LIQUID AKUMINUM FORMED UNDER THE ARC TO FLOW AWAY FROM THE ARC AND OVER THE NON-REACTED PORTION OF
Claim 3
Dependent Claim
37 words
The process of claim 1 wherein the charge comprises alumina, aluminum carbide, carbon, and other carbon-aluminum compounds and the composite analysis of the charge has a carbon to oxygen atomic ratio of 1:1 + or - 0.05.
Claim 4
Dependent Claim
15 words
The process of claim 1 in which the open electrical arc is a plasma torch.
Claim 5
Dependent Claim
24 words
The process of claim 1 in which the arc is intermittently applied to the charge in a cycle time of 1/120 to 90 seconds.
Claim 6
Dependent Claim
17 words
The process of claim 4 wherein the arc is intermittently applied by ending and restarting the arc.
Claim 7
Dependent Claim
33 words
The process of claim 1 wherein the energy supplied to the arc provides an average electrical density of from 10 to 50 kw per square inch of charge area struck by the arc.
Claim 8
Dependent Claim
16 words
The process of claim 1 wherein temperature of major portion of unreacted charge is below 1,800*C.
Claim 9
Dependent Claim
29 words
The process of claim 1 wherein the temperature of furnace parts which contain carbon and which come in contact with the product aluminum are maintained at temperatures below 1,800*C.
Claim 10
Dependent Claim
18 words
The process of claim 1 wherein the charge is supported on a rotating hearth in the furnace chamber.
Claim 11
Dependent Claim
19 words
The process of claim 1 wherein the system pressure within the furnace chamber is from 0.1 to 10 atmosphere.
Claim 12
Dependent Claim
25 words
The process of claim 1 wherein the liquid aluminum removed from the charge is collected in a pool maintained at the temperature of about 670*-1800*C.
Claim 13
Dependent Claim
36 words
The process of claim 11 wherein the said collected pool of molten aluminum and the charge and arc extending to the charge are enclosed in a furnace chamber which is substantially closed to the outside atmosphere.
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) | 1978-12-29 | 1979-06-30 | 1979-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-29 | 1983-06-30 | 1983-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-29 | 1987-06-30 | 1987-12-30 | $7700.00 | Window Closed / Lapsed |