US5141734A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Steam producing process
Assignee: Alcoa Corp
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Filing: 1990-04-24
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Granted: 1992-08-25
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Expires: 2010-04-24
Abstract
Abstract In a process utilizing steam, the method of producing at least a portion of said steam, including heating a water-containing, solid substance for generating steam and capturing the generated steam for said process. A suitable solid substance is Al(OH) 3 . New alumina products and uses therefor are obtained.
Inventors
- 👤 Chanakya Misra
- 👤 Steven W. Sucech
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:06
CPC Classifications
C; C01; C01B; C01B5/00; C01F; C01F7/00; C01F7/02; C01F7/44; C01F7/441; C01F7/445; F; F22; F22B; F22B1/00; C01P; C01P2002/00; C01P2002/02; C01P2004/00; C01P2004/01; C01P2004/03; C01P2004/60; C01P2004/61; C01P2006/00; C01P2006/12
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
148 words
In a process utilizing steam, the method of producing and supplying at least a portion of said steam, comprising the steps of (a) heating a solid Al(OH) 3 at a temperature greater than 250° C. in a decomposer at a pressure greater than one atmosphere gage pressure i. for decomposing said Al(OH) 3 to drive off chemically combined water, and ii. for yielding said water in the form of steam which is essentially 100% H 2 O at a pressure greater than one atmosphere gage pressure, (b) removing said steam from the decomposer while keeping said steam at a pressure greater than one atmosphere gage pressure, (c) capturing said steam, still at a pressure greater than one atmosphere gage pressure, for said process, said process being external to said decomposer, and (d) feeding said steam, still at a pressure greater than one atmosphere gage pressure, to said process.
Claim 2
Dependent Claim
148 words
In a process utilizing steam, the method of producing and supplying at least a portion of said steam, comprising the steps of (a) heating a solid Al(OH) 3 at a temperature greater than 250° C. in a decomposer at a pressure greater than one atmosphere gage pressure i. for decomposing said Al(OH) 3 to drive off chemically combined water, and ii. for yielding said water in the form of steam which is essentially 100% H 2 O at a pressure greater than one atmosphere gage pressure, (b) removing said steam from the decomposer while keeping said steam at a pressure greater than one atmosphere gage pressure, (c) capturing said steam, still at a pressure greater than one atmosphere gage pressure, for said process, said process being external to said decomposer, and (d) feeding said steam, still at a pressure greater than one atmosphere gage pressure, to said process.
Claim 3
Dependent Claim
27 words
A method as claimed in claim 1, wherein temperature, pressure, and time in the step of heating are insufficient to convert said Al(OH) 3 to alpha alumina.
Claim 4
Dependent Claim
23 words
A method as claimed in claim 1, wherein the aluminum hydroxide comprises a bed in the step of heating, said bed being fluidized.
Claim 5
Dependent Claim
13 words
A method as claimed in claim 3, wherein said water self-fluidizes the bed.
Claim 6
Dependent Claim
21 words
A method as claimed in claim 1, the step of heating being carried out in the range up to 650° C.
Claim 7
Dependent Claim
19 words
A method as claimed in claim 5, the step of heating being carried out in the range 350°-650° C.
Claim 8
Dependent Claim
19 words
A method as claimed in claim 6, the step of heating being carried out in the range 400°-650° C.
Claim 9
Dependent Claim
38 words
A method as claimed in claim 1, wherein the process utilizing steam comprises treating a slurry of bauxite ore with sodium hydroxide solution to dissolve aluminum values while maintaining temperature and pressure conditions of the slurry with steam.
Claim 10
Dependent Claim
18 words
A method as claimed in claim 1, wherein the step of heating comprises indirect heating with combustion gases.
Claim 11
Dependent Claim
43 words
A method as claimed in claim 8, wherein the solid substance comprises Al(OH) 3 , the step of heating comprises indirect heating, and the temperature, pressure and time in the step of heating are insufficient to convert the Al(OH) 3 to alpha alumina.
References Cited (Backward Citations)
CA507723A
Cited
US4224288A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-08-25 | 1996-02-24 | 1996-08-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-08-25 | 2000-02-24 | 2000-08-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-08-25 | 2004-02-24 | 2004-08-25 | $7700.00 | Window Closed / Lapsed |