US3763050A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of recovering a rare earth phosphor
Assignee: US Philips Corp
•
Filing: 1971-06-11
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Granted: 1973-10-02
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Expires: 1991-06-11
Abstract
Abstract A method of recovering a rare earth phosphor from a mixture which contains this phosphor and at least one sulphide and/or selenide of zinc and/or cadmium. The mixture is treated in an aqueous alkaline solution which contains a hypohalogenite and whose pH is larger than 12. The rare earth phosphor is subsequently separated from the liquid and washed with water, optionally after rinsing with a diluted acid.
Inventors
- 👤 J Dikhoff
- 👤 Boer F De
- 👤 D Barneveld
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 08:27
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/01; C01; C01F; C01F17/00; C01F17/20; C01F17/206; C01F17/218; C01F17/224; C01F17/288; C01F17/294; Y; Y02; Y02W; Y02W30/00; Y02W30/50
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
29 words
A method as claimed in claim 1 wherein the alkaline solution contains at least 4 gram mol of hypobromite or hypochlorite per gram mol of sulfide and/or selenide present.
Claim 2
Dependent Claim
23 words
A method as claimed in claim 2, wherein the aqueous solution contains at least 1 gram mol of NaPH or KOH per litre.
Claim 3
Dependent Claim
14 words
A method as claimed in claim 2 wherein NaClO is used as the hypochlorite.
Claim 4
Dependent Claim
24 words
A method as claimed in claim 2, wherein the separated rare earth phosphor is rinsed with dilute acid before it is washed with water.
References Cited (Backward Citations)
US3348924A
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US3360674A
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US3368980A
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US3474040A
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US3523904A
Cited
US3577351A
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US3625659A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-01 | 1977-04-02 | 1977-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-01 | 1981-04-02 | 1981-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-01 | 1985-04-02 | 1985-10-02 | $7700.00 | Window Closed / Lapsed |