US3660076A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Treatment of material removed from molten aluminum
Assignee: Alcan Research and Development Ltd
•
Filing: 1970-09-17
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Granted: 1972-05-02
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Expires: 1990-09-17
Abstract
Abstract Material such as is skimmed from the surface of molten aluminum in a casting furnace, which usually contains considerable aluminum metal along with chemical compounds such as alumina, is crushed and treated with dry steam at a moderately elevated temperature, so that unwanted carbides and nitrides are eliminated and the treated skim or the like is conditioned for recovery of useful values, advantageously by classification thereafter into a coarse fraction providing aluminum metal suitable for remelting and a fine fraction in which chemical material is reclaimed, that may include values suitable for use in the fused bath of an aluminum reduction cell.
Inventors
- 👤 Meriyn M Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 21:00
CPC Classifications
C; C22; C22B; C22B21/00; C22B21/0007; C22B7/00; C22B7/04; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
27 words
A method as defined in claim 1, in which said steam treatment is effected at a temperature not higher than about 400* for at least several hours.
Claim 2
Dependent Claim
29 words
A method as defined in claim 2, in which said steam treatment is effected at a pressure of at least about 15 psi for at least about 4 hours.
Claim 3
Dependent Claim
46 words
A method as defined in claim 2 in which said segregated material, as subjected to said steam treatment, has particle sizes not greater than about 4 inches, and said steam treatment is effected for a period of time in a range up to about 10 hours.
Claim 4
Dependent Claim
25 words
A method as defined in claim 4, in which said steam treatment is effected at a temperature in the range of 250* to 450* F.
Claim 5
Dependent Claim
52 words
A method as defined in claim 1, in which said segregated material which is treated contains material of the class consisting of carbide and nitride, and said treating step is effective for reaction of said steam with said last-mentioned material to release gaseous product of the class consisting of hydrocarbon and ammOnia.
Claim 6
Dependent Claim
34 words
A method as defined in claim 6, in which said segregated material which is treated contains aluminum oxide, and said treating step is effective for hydration of at least some of said aluminum oxide.
Claim 7
Dependent Claim
72 words
A method as defined in claim 1, in which said segregated material that is treated contains at least about 20 percent aluminum metal, and which includes classifying the product of said steam treatment into said fine and coarser fractions, said treating and classifying steps coacting to yield said coarser fraction having a percentage content of aluminum metal substantially greater than the content of said metal in the segregated material that is treated.
Claim 8
Independent Claim
185 words
A method of treating skim which is removed from the surface of molten aluminum and which contains aluminum metal, unwanted material of the class consisting of aluminum carbide and nitride, and chemical material of the class consisting of fluoride, oxide and hydroxide of aluminum and sodium, comprising crushing said skim, treating the crushed skim in a confined region with dry steam for converting the unwanted material to gaseous product and to material which is of the class of aluminum oxide and hydroxide and which augments said chemical material in the crushed skim, while maintaining the crushed skim at a temperature, below the melting point of aluminum, insufficient for substantial loss of aluminum metal by reaction in the region, and while withdrawing said gaseous product from the region, to yield a substantially dry, particulate product of the skim, classifiable by particle size into a fine, chemical-containing fraction, which has a substantially higher content of chemical material of the aforesaid class than the skim which was treated, and a coarser fraction, which contains aluminum metal in a substantially higher proportion than in the skim which was treated.
Claim 9
Dependent Claim
27 words
A method as defined in claim 9, in which said steam treatment is effected at superatmospheric pressure and at a temperature not higher than about 400* F.
Claim 10
Dependent Claim
30 words
A method as defined in claim 10, in which said skim has particle sizes less than about three-fourths inch and said steam treatment is effected for at least several hours.
Claim 11
Dependent Claim
29 words
A method as defined in claim 11, in which said steam treatment is effected at pressure of about 15 to 40 psi and for about 4 to 10 hours.
Claim 12
Dependent Claim
70 words
A method as defined in claim 9, in which said skim which is treated contains at least about 20 percent aluminum metal, and said steam treatment is effected at superatmospheric pressure and yields said product classifiable into said fractions of which the fine fraction is suitable for employment as chemical addition in the molten bath of a reduction cell and the coarser fraction is suitable for remelting as aluminum metal.
Claim 13
Dependent Claim
27 words
A method as defined in claim 13, which includes the step of subjecting said product to classification by particle size to separate said fine and coarser fractions.
Claim 14
Dependent Claim
35 words
A method as defined in claim 14, in which said fine fraction consists of and is separated as material having particle size smaller than a predetermined value which is not greater than about one-eighth inch.
Claim 15
Dependent Claim
22 words
A method as defined in claim 9, in which said skim which is treated contains at least about 3 percent aluminum metal.
Claim 16
Dependent Claim
133 words
In a method of treating segregated material which is separated from a body of molten aluminum after accumulation during standing of said molten aluminum and which contains unwanted material of the class consisting of aluminum carbide and nitride, and chemical material of the class consisting of fluoride, oxide and hydroxide of aluminum and sodium, the step of treating fragments of said segregated material in a confined region with dry steam at a temperature not higher than about 400* F. for a sufficient time to convert the unwanted material to gaseous product and to material which is of the class of aluminum oxide and hydroxide and which augments said chemical material in the Segregated material, to yield a product that affords recovery of chemical material of the aforesaid class in substantially dry, particulate form.
Claim 17
Dependent Claim
74 words
A method as defined in claim 17, in which said segregated material which is treated contains aluminum metal, and in which said treatment of the segregated material yields a product which is capable of treatment for classification by particle size to separate, from a coarser fraction, a fine, chemical-containing fraction having a substantially lower proportion of aluminum metal and a substantially higher content of said chemical material than said segregated material which is treated.
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) | 1975-05-02 | 1975-11-01 | 1976-05-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-02 | 1979-11-01 | 1980-05-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-02 | 1983-11-01 | 1984-05-02 | $7700.00 | Window Closed / Lapsed |