US4297325A
Expired / Lapsed
US
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Method of producing pseudoboehmite from aluminum salt solutions
Assignee: Filtrol Corp
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Filing: 1980-12-08
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Granted: 1981-10-27
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Expires: 2000-12-08
Abstract
Abstract The production process for pseudoboehmite from leach liquors produced in the acid treatment of clays, which liquors contain Fe and alkaline earth ions.
Inventors
- 👤 Julius Scherzer
- 👤 Anh-Thu Liu
- 👤 Yih-Yau Sun
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:04
CPC Classifications
B; B01; B01J; B01J29/00; B01J29/04; B01J29/06; B01J29/08; B01J21/00; B01J21/02; B01J21/04; C; C01; C01F; C01F7/00; C01F7/02; C01F7/20; C01F7/26; C01F7/34; B01J2229/00; B01J2229/30; B01J2229/42; B01J37/00; B01J37/0009; B01J37/0027; B01J37/0045
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
100 words
A method for producing pseudoboehmite from aluminum sulfate solutions containing Fe +++ , and alkaline earth ions which comprises adding a reducing agent and reducing Fe +++ to Fe ++ without precipitating compounds of the Fe, or alkaline earth ions and then adjusting the pH in the range of about 4 to about 5 to form alumina hydrate gel without precipitating any substantial quantities of Fe or alkaline earth compounds, separating the gel from the leach solution aging the gel at a pH in excess of about 9 and forming pseudoboehmite substantially free of Fe and of alkaline earth cations.
Claim 2
Independent Claim
100 words
A method for producing pseudoboehmite from aluminum sulfate solutions containing Fe +++ , and alkaline earth ions which comprises adding a reducing agent and reducing Fe +++ to Fe ++ without precipitating compounds of the Fe, or alkaline earth ions and then adjusting the pH in the range of about 4 to about 5 to form alumina hydrate gel without precipitating any substantial quantities of Fe or alkaline earth compounds, separating the gel from the leach solution aging the gel at a pH in excess of about 9 and forming pseudoboehmite substantially free of Fe and of alkaline earth cations.
Claim 3
Independent Claim
102 words
A method for producing pseudoboehmite from aluminum sulfate solutions containing Fe +++ , and alkaline earth ions which comprises adding a thiosulfate to said solution and reducing Fe +++ to Fe ++ without precipitating compounds of the Fe, or alkaline earth ions and then adjusting the pH in the range of about 4 to about 5 to form alumina hydrate gel without precipitating any substantial quantities of Fe or alkaline earth compounds, separating the gel from the leach solution aging the gel at a pH in excess of about 9 and forming pseudoboehmite substantially free of Fe and of alkaline earth cations.
Claim 4
Independent Claim
102 words
A method for producing pseudoboehmite from aluminum sulfate solutions containing Fe +++ , and alkaline earth ions which comprises adding a thiosulfate to said solution and reducing Fe +++ to Fe ++ without precipitating compounds of the Fe, or alkaline earth ions and then adjusting the pH in the range of about 4 to about 5 to form alumina hydrate gel without precipitating any substantial quantities of Fe or alkaline earth compounds, separating the gel from the leach solution aging the gel at a pH in excess of about 9 and forming pseudoboehmite substantially free of Fe and of alkaline earth cations.
Claim 5
Independent Claim
113 words
A method for producing pseudoboehmite from aluminum sulfate solutions containing Fe +++ , and alkaline earth ions which comprises adding sodium thiosulfate to said solution at a pH in the range of about 1 to about 3, and reducing Fe +++ to Fe++ without precipitating compounds of the Fe, or alkaline earth ions and then adjusting the pH in the range of about 4 to about 5 to form alumina hydrate gel without precipitating any substantial quantities of Fe or alkaline earth compounds, separating the gel from the leach solution aging the gel at a pH in excess of about 9 and forming pseudoboehmite substantially free of Fe and of alkaline earth cations.
Claim 6
Independent Claim
113 words
A method for producing pseudoboehmite from aluminum sulfate solutions containing Fe +++ , and alkaline earth ions which comprises adding sodium thiosulfate to said solution at a pH in the range of about 1 to about 3, and reducing Fe +++ to Fe++ without precipitating compounds of the Fe, or alkaline earth ions and then adjusting the pH in the range of about 4 to about 5 to form alumina hydrate gel without precipitating any substantial quantities of Fe or alkaline earth compounds, separating the gel from the leach solution aging the gel at a pH in excess of about 9 and forming pseudoboehmite substantially free of Fe and of alkaline earth cations.
Claim 7
Independent Claim
130 words
A method for producing pseudoboehmite from aluminum sulfate solutions containing Fe +++ , and alkaline earth ions which comprises adding sodium thiosulfate to said solution at a pH in the range of about 1 to about 3, in amount equivalent to more than about 2 moles of said thiosulfate per gram atom of Fe, and reducing Fe +++ to Fe++ without precipitating compounds of the Fe, or alkaline earth ions and then adjusting the pH in the range of about 4 to about 5 to form alumina hydrate gel without precipitating any substantial quantities of Fe or alkaline earth compounds, separating the gel from the leach solution aging the gel at a pH in excess of about 9 and forming pseudoboehmite substantially free of Fe and of alkaline earth cations.
Claim 8
Independent Claim
130 words
A method for producing pseudoboehmite from aluminum sulfate solutions containing Fe +++ , and alkaline earth ions which comprises adding sodium thiosulfate to said solution at a pH in the range of about 1 to about 3, in amount equivalent to more than about 2 moles of said thiosulfate per gram atom of Fe, and reducing Fe +++ to Fe++ without precipitating compounds of the Fe, or alkaline earth ions and then adjusting the pH in the range of about 4 to about 5 to form alumina hydrate gel without precipitating any substantial quantities of Fe or alkaline earth compounds, separating the gel from the leach solution aging the gel at a pH in excess of about 9 and forming pseudoboehmite substantially free of Fe and of alkaline earth cations.
Claim 9
Dependent Claim
49 words
The process of claim 1, 2, 3 or 4, in which the gel is formed at a pH in the range of about 4 to about 5 by addition of a solution of NH 4 OH containing less than about 10% by weight of NH 3 in the solution.
Claim 10
Dependent Claim
55 words
The process of claim 1, 2, 3 or 4, in which the gel is formed at a pH in the range of about 4 to about 5 by the addition of a solution (NH 4 ) 2 CO 3 containing less than about 20% by weight of the (NH 4 ) 2 CO 3 .
Claim 11
Dependent Claim
44 words
The process of claim 1, 2, 3 or 4, in which the gel is formed at a pH in the range of about 4 to about 5 by addition of a solution of NaOH containing less than about 20% by weight of the NaOH.
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) | 1984-10-26 | 1985-04-27 | 1985-10-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-10-26 | 1989-04-27 | 1989-10-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-10-26 | 1993-04-27 | 1993-10-27 | $7700.00 | Window Closed / Lapsed |