Patent US3711600A successfully refreshed from Google Patents.
US3711600A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing calcined oxides
Assignee: United States Atomic Energy Commission
•
Filing: 1970-12-22
•
Granted: 1973-01-16
•
Expires: 1990-12-22
Abstract
Abstract A method for preparing calcined calcium oxide or magnesium oxide, particularly in high-bulk-density form. An aqueous solution of the nitrate of the alkaline earth metal is made strongly basic to precipitate the hydroxide. The precipitate is recovered and then washed to reduce the nitrate concentration therein to within 0.5 to 15 weight percent. The washed precipitate is calcined at from 1,200 to 1,500*C for about 5 to 30 hours to produce the desired oxide.
Inventors
- 👤 B Sturm
- 👤 R Quincy
- 👤 C Butler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:15
CPC Classifications
C; C01; C01F; C01F5/00; C01F5/14; C01F5/22; C01F5/02; C01F5/06; C01F5/08; C01F5/20; C01P; C01P2006/00; C01P2006/10
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
31 words
The method of claim 1 wherein said washing is conducted to reduce the nitrate concentration in said precipitate to a value in the range of from 1 to 4 weight percent.
Claim 2
Dependent Claim
21 words
The method of claim 1 wherein said calcining step is conducted for a period of from about 5 to 30 hours.
Claim 3
Dependent Claim
24 words
The method of claim 1 wherein the concentration of said nitrate in said feed solution iS in the range of 2.5 to 3.5 M.
Claim 4
Dependent Claim
25 words
The method of claim 1 wherein said hydroxide is precipitated from said feed solution by adjusting the pH thereof to a value above about 10.
Claim 5
Dependent Claim
45 words
The method of claim 1 wherein said feed solution is prepared by combining water and a nitrate of the selected metal, said nitrate having been prepared by crystallization from a concentrated solution of said nitrate at a pH in the range of 1 to 7.
Claim 6
Dependent Claim
69 words
The method of claim 1 wherein said feed solution is prepared by the following steps: dissolving the oxide of the selected metal in nitric acid, separating the resulting nitrate solution from the undissolved residue, adjusting the pH of the separated nitrate solution to within the range of 7.5 to 8.3 to precipitate iron and aluminum impurities, and separating the resulting purified nitrate solution for use as said feed solution.
Claim 7
Dependent Claim
42 words
The method of claim 7 wherein the pH of said nitrate solution is adjusted with a water-soluble base having an ionization constant above about 10 6 and selected from the group consisting of ammonium hydroxide, substituted ammonium hydroxides, aliphatic hydroxylamines, and hydrazine.
References Cited (Backward Citations)
US1975954A
Cited
US2130240A
Cited
US2641529A
Cited
US2801155A
Cited
US2912306A
Cited
US3341290A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-16 | 1976-07-17 | 1977-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-16 | 1980-07-17 | 1981-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-16 | 1984-07-17 | 1985-01-16 | $7700.00 | Window Closed / Lapsed |