Patent US3175883A successfully refreshed from Google Patents.
US3175883A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for reducing the soda content of alumina
Assignee: Alcan Research and Development Ltd
•
Filing: 1961-06-05
•
Granted: 1965-03-30
•
Expires: 1981-06-05
Abstract
No abstract record available.
Inventors
- 👤 Lindsay James Gordon
- 👤 Gailey Hugh Joseph
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:50
CPC Classifications
C; C04; C04B; C04B33/00; C04B33/02; C04B33/04; C04B33/06; C01; C01F; C01F7/00; C01F7/02; C01F7/021; C01F7/44; C01F7/441; C01F7/442; C01F7/46; C04B33/30; C01P; C01P2004/00; C01P2004/60; C01P2004/61
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
171 words
A METHOD OF TREATING SODA-CONTAMINATED ALUMINA HYDRATE TO REDUCE THE SODA CONTENT THEREOF AND TO PROVIDE A SUBSTANTIAL 100% CRYSTALLINE ALPHA-ALUMINA PRODUCT HAVING A DESIRED AVERAGE CRYSTAL SIZE IN THE RANGE 5-12 MICRONS WHICH COMPRISES CALCINING SODA-CONTAMINATED, PARTICLE-FORM ALUMINA HYDRATE AT AN ELEVATED TEMPERATURE FROM ABOUT 1000*C. UP TO THE MELTING POINT OF ALUMINA IN THE PRESENCE OF GASEOUS ELEMENTAL CHLORINE AND ALUMINUM TRIFLUROIDE, SAID CHLORINE AND SAID ALUMINUM TRIFLUORIDE BEING EMPLOYED IN AN AMOUNT LIN THE RANGE 0.5-10% AND 0.01-5% BY WEIGHT, RESPECTIVELY, BASED ON TEH RESULTING TREATED ALUMINA AND BEING CAPABLE OF YIELDING WITH THE SODA IN SAID ALUMINA HYDRATE AT THE AFORESAID CALCINING TEMPERATURE A VOLATILIZABLE SODIUM COMPOUND, THE AFORESAID CALCINING OPERATION BEING CARRIED OUT FOR A PERIOD OF TIME IN THE RANGE 0.3-3.5 HOURS SUFFICIENT TO REDUCE THE SODA CONTENT OF SAID SODA-CONTAMINATED ALUMINA HYDRATE BY AT LEAST ABOUT 30%, AND RECOVERING AS PRODUCT THE RESULTILNG TREATED ALUMINA CHARACTERIZED AS A SUBSTANTIALLY 100% CRYSTALLINE ALPHA-ALUMINA PRODUCT HAVING A DESIRED AVERAGE CRYSTAL SIZE IN THE RANGE 5-12 MICRONS.
Claim 2
Independent Claim
171 words
A METHOD OF TREATING SODA-CONTAMINATED ALUMINA HYDRATE TO REDUCE THE SODA CONTENT THEREOF AND TO PROVIDE A SUBSTANTIAL 100% CRYSTALLINE ALPHA-ALUMINA PRODUCT HAVING A DESIRED AVERAGE CRYSTAL SIZE IN THE RANGE 5-12 MICRONS WHICH COMPRISES CALCINING SODA-CONTAMINATED, PARTICLE-FORM ALUMINA HYDRATE AT AN ELEVATED TEMPERATURE FROM ABOUT 1000*C. UP TO THE MELTING POINT OF ALUMINA IN THE PRESENCE OF GASEOUS ELEMENTAL CHLORINE AND ALUMINUM TRIFLUROIDE, SAID CHLORINE AND SAID ALUMINUM TRIFLUORIDE BEING EMPLOYED IN AN AMOUNT LIN THE RANGE 0.5-10% AND 0.01-5% BY WEIGHT, RESPECTIVELY, BASED ON TEH RESULTING TREATED ALUMINA AND BEING CAPABLE OF YIELDING WITH THE SODA IN SAID ALUMINA HYDRATE AT THE AFORESAID CALCINING TEMPERATURE A VOLATILIZABLE SODIUM COMPOUND, THE AFORESAID CALCINING OPERATION BEING CARRIED OUT FOR A PERIOD OF TIME IN THE RANGE 0.3-3.5 HOURS SUFFICIENT TO REDUCE THE SODA CONTENT OF SAID SODA-CONTAMINATED ALUMINA HYDRATE BY AT LEAST ABOUT 30%, AND RECOVERING AS PRODUCT THE RESULTILNG TREATED ALUMINA CHARACTERIZED AS A SUBSTANTIALLY 100% CRYSTALLINE ALPHA-ALUMINA PRODUCT HAVING A DESIRED AVERAGE CRYSTAL SIZE IN THE RANGE 5-12 MICRONS.
References Cited (Backward Citations)
US2411806A
Cited
US2411807A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1968-03-29 | 1968-09-28 | 1969-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-03-29 | 1972-09-28 | 1973-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-03-29 | 1976-09-28 | 1977-03-30 | $7700.00 | Window Closed / Lapsed |