US3919403A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for the production of alpha alumina monohydrate
Assignee: WR Grace and Co
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Filing: 1972-07-17
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Granted: 1975-11-11
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Expires: 1992-07-17
Abstract
Abstract Basic aluminum sulfate can be homogeneously precipitated from an aluminum sulfate solution by the in situ decomposition of an ammonia yielding compound within the aluminum sulfate solution. The preferred ammonia yielding compounds are urea, thiourea, biuret, guanidine and salts and derivatives thereof. Ammonium hydroxide, sodium hydroxide, potassium hydroxide or sodium aluminate is then added to the basic aluminum sulfate to yield an alpha alumina monohydrate of unique pore and extrusion characteristics.
Inventors
- 👤 Joseph B Pullen
- 👤 Burton L Mobley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:52
CPC Classifications
C; C01; C01F; C01F7/00; C01F7/02; C01F7/34; C01F7/68; C01F7/74; C01P; C01P2006/00; C01P2006/10; C01P2006/12; C01P2006/14
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
146 words
A PROCESS FOR PRODUCING ALPHA ALUMINA MONOHYDRATE HAVING A PORE VOLUME OF 0.65 TO 0.85 C.C./G., A PORE DIAMETER OF 95 TO 125 ANGSTROMS AND A SURFACE AREA OF 200 TO 300 M2/G. COMPRISING: FORMING AN AQUEOUS SOLUTION OF ALUMINUM SULFATE; ADDING AMMONIA TO RAISE THE PH OF SAID ALUMINUM SULFATE SOLUTION TO ABOUT 2.7 TO 3.5; ADMIXING A COMPOUND WHICH WIL YIELD AMMONIA ON THERMAL DECOMPOSITION IN AN AMOUNT SUFFICIENT TO RAISE THE ADMIXTURE TO A PH OF ABOUT 4.5 TO 6.0 AFTER DECOMPOSITION OF SAID COMPOUND; HEATING SAID ADMIXTURE TO THERMALLY DECOMPOSE SAID AMMONIA YIELDING COMPOUND AND HOMOGENEOUSLY PRECIPITATING BASIC ALUMINUM SULFATE; ADDING A BASIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF SODIUM HYDROXIDE, POTASSIUM HYDROXIDE, AMMONIUM HYDROXIDE OR SODIUM ALUMINATE TO SAID ADMIXTURE, THEREBY INCREASING THE PH TO ABOUT 9.0 TO 10.5 AND FORMING ALPHA ALUMINA MONOHYDRATE; AND RECOVERING SAID ALPHA ALUMINA MONOHYDRATE.
Claim 2
Dependent Claim
146 words
A PROCESS FOR PRODUCING ALPHA ALUMINA MONOHYDRATE HAVING A PORE VOLUME OF 0.65 TO 0.85 C.C./G., A PORE DIAMETER OF 95 TO 125 ANGSTROMS AND A SURFACE AREA OF 200 TO 300 M2/G. COMPRISING: FORMING AN AQUEOUS SOLUTION OF ALUMINUM SULFATE; ADDING AMMONIA TO RAISE THE PH OF SAID ALUMINUM SULFATE SOLUTION TO ABOUT 2.7 TO 3.5; ADMIXING A COMPOUND WHICH WIL YIELD AMMONIA ON THERMAL DECOMPOSITION IN AN AMOUNT SUFFICIENT TO RAISE THE ADMIXTURE TO A PH OF ABOUT 4.5 TO 6.0 AFTER DECOMPOSITION OF SAID COMPOUND; HEATING SAID ADMIXTURE TO THERMALLY DECOMPOSE SAID AMMONIA YIELDING COMPOUND AND HOMOGENEOUSLY PRECIPITATING BASIC ALUMINUM SULFATE; ADDING A BASIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF SODIUM HYDROXIDE, POTASSIUM HYDROXIDE, AMMONIUM HYDROXIDE OR SODIUM ALUMINATE TO SAID ADMIXTURE, THEREBY INCREASING THE PH TO ABOUT 9.0 TO 10.5 AND FORMING ALPHA ALUMINA MONOHYDRATE; AND RECOVERING SAID ALPHA ALUMINA MONOHYDRATE.
Claim 3
Dependent Claim
27 words
A process as in claim 1 wherein said ammonia yielding compound is selected from the group consisting of urea, thiourea, biuret, guanidine and salts and derivatives thereof.
Claim 4
Dependent Claim
24 words
A process as in claim 2 wherein said aluminum sulfate solution contains from about 5 percent to about 30 percent aluminum sulfate by weight.
Claim 5
Dependent Claim
13 words
A process as in claim 3 wherein the ammonia yielding compound is urea.
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) | 1978-11-10 | 1979-05-12 | 1979-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-10 | 1983-05-12 | 1983-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-10 | 1987-05-12 | 1987-11-11 | $7700.00 | Window Closed / Lapsed |