US3607371A
Expired / Lapsed
US
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Phosphate-coated rare-earth oxide compositions and a process for producing same
Assignee: GTE Sylvania Inc
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Filing: 1969-10-30
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Granted: 1971-09-21
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Expires: 1989-10-30
Abstract
Abstract Rare-earth oxide compositions can be improved in handling characteristics by increasing the bulk density of the compound by uniformly coating the finely divided particles with a corresponding rare-earth phosphate. Aqueous media comprising suspensions of finely divided particles of rare-earth oxide compositions and a water-soluble orthophosphate source are agitated under controlled pH conditions for sufficient lengths of time to dissolve sufficient amounts of the rare-earth oxide compositions, and to reprecipitate them to form solid rare-earth-phosphate-coated rare-earth compounds. The solids are then separated from the aqueous phases, washed with water, and heat-treated for sufficient lengths of time.
Inventors
- 👤 James W Haynes
- 👤 Kenneth H Shaner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:31
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/77; C09K11/7766; C09K11/7767; C09K11/7769; C01; C01F; C01F17/00; C01F17/20; C01F17/206; C01F17/241; C09K11/7709; H; H10; H10P; H10P95/00; C01P; C01P2006/00; C01P2006/10
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
27 words
A composition according to claim 1, wherein said rare-earth oxide has a cation selected from the group consisting of yttrium, gadolinium, lanthanum, lutetium, europium, and mixtures thereof.
Claim 2
Dependent Claim
36 words
A composition according to claim 1, wherein said rare-earth oxide is a rare-earth-activated rare-earth oxide phosphor and said rare-earth oxide is selected from the group consisting of oxides of yttrium, gadolinium, lanthanum, lutetium and mixtures thereof.
Claim 3
Dependent Claim
21 words
A composition according to claim 3, wherein said activator is selected from the group consisting of europium, semarium, praseodymium, and terbium.
Claim 4
Dependent Claim
30 words
A composition according to claim 1, wherein said rare-earth oxide composition has an average bulk density of from about 2 g./cc. to about 8 g./cc. greater than uncoated rare-earth oxide.
Claim 5
Dependent Claim
148 words
In a process for preparing rare-earth-phosphate-coated rare-earth oxide compositions, the steps comprising a. forming an aqueous medium comprising a suspension of finely divided particles an aqueous medium comprising a suspension of finely divided particles of a rare-earth oxide and a water-soluble orthophosphate source, wherein said orthophosphate is present in an amount of about 0.002 percent to about 10.5 percent, by weight, with respect to the weight of said oxide, b. adjusting the pH of the resultant suspension, while agitating, from about 4 to about 5, c. maintaining said pH, while agitating, for at least about 10 minutes, to thereby form a solid rare-earth-phosphate-coated rare-earth oxide, d. separating said coated solid, e. washing said coated solid with at least about 5 cc. water per gram of said solid, and f. thereafter heating said coated solid from about 100* C. to about 1,200* C. for at least about one-half hour.
Claim 6
Dependent Claim
25 words
A process according to claim 6, wherein said water-soluble orthophosphate is selected from the group consisting of ammonium orthophosphates, alkali metal orthophosphates, and mixtures thereof.
Claim 7
Dependent Claim
13 words
A process according to claim 7, wherein said water-soluble orthophosphate is monoammonium orthophosphate.
Claim 8
Dependent Claim
13 words
A process according to claim 6, wherein said water-soluble orthophosphate is orthophosphoric acid.
Claim 9
Dependent Claim
27 words
A process according to claim 6, wherein said rare-earth oxide has a cation selected from the group consisting of yttrium, gadolinium, lanthanum, lutetium, europium and mixtures thereof.
Claim 10
Dependent Claim
37 words
A process according to claim 6, wherein said rare-earth oxide is a rare-earth-activated rare-earth oxide phosphor and wherein said rare-earth oxide is selected from the group consisting of oxides of yttrium, gadolinium, lanthanum, lutetium, and mixtures thereof.
Claim 11
Dependent Claim
19 words
A process according to claim 6, wherein said pH is held from about 10 minutes to about 30 minutes.
Claim 12
Dependent Claim
20 words
A process according to claim 6, wherein said coated solid is heated for about one-half hour to about 2 hours.
Claim 13
Dependent Claim
28 words
A process according to claim 6, wherein said pH is adjusted with a mineral acid selected from the group consisting of nitric acid, hydrochloric acid, and orthophosphoric acid.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-20 | 1975-03-22 | 1975-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-20 | 1979-03-22 | 1979-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-20 | 1983-03-22 | 1983-09-21 | $7700.00 | Window Closed / Lapsed |