US3748095A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of high purity rare earth sulfides
Assignee: McDonnell Douglas Corp
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Filing: 1968-06-17
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Granted: 1973-07-24
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Expires: 1988-06-17
Abstract
Abstract Novel method for the production of high purity metal sulfides, selenides, tellurides, and arsenides, particularly those of high melting point greater than 1,000* C, e.g., such compounds of the rare earth metals. An anhydrous metal, metal salt, metal oxide or mixtures thereof is contacted with a gas mixture, e.g., H2S and CS2 at a high temperature, e.g., in the range of about 1,250* C to about 1,325* C, in the substantial absence of water vapor and oxygen until the product has been formed. The metal sulfides, tellurides, selenides, and arsenides thus produced are formed into single crystals which are useful as semi-conductors, transistors, etc.
Inventors
- 👤 J Henderson
- 👤 D Johnson
- 👤 M Muramoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 21:19
CPC Classifications
C; C22; C22C; C22C1/00; C22C1/007; C01; C01B; C01B19/00; C01B19/007; C01F; C01F17/00; C01F17/20; C01F17/288; C30; C30B; C30B11/00; C30B29/00; C30B29/10; C30B29/46; C01P; C01P2006/00; C01P2006/32; C01P2006/33; C01P2006/34; C01P2006/40
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
24 words
A method as defined In claim 1, wherein said substance is selected from the group consisting of the rare earth oxides of said metal.
Claim 2
Dependent Claim
30 words
A method as defined in claim 1, wherein said substance is an oxide of a rare earth metal selected from the group consisting of Nd, Sm, Gd, Dy and Y.
Claim 3
Dependent Claim
89 words
A method as defined in claim 2, wherein said gas mixture is in proportion of from about 50 to about 98 percent of H2S and from about 50 to about 2 percent of CS2, said gas mixture being supplied to said metal reactant so that at least 100 moles (STP) of gas mixture flows over each mole of the metal reactant calculated as available cation, said reaction is conducted in a reaction chamber composed of a substance selected from the group consisting of pyrolytic graphite and pyrolytic boron nitride.
Claim 4
Dependent Claim
21 words
A method as defined in claim 1, wherein the reaction temperature is in the range of about 1,250* to about 1,325*C.
Claim 5
Dependent Claim
23 words
A method as defined in claim 1, wherein the H2S gas mixture is produced by bubbling gas into the liquid form of CS2.
Claim 6
Dependent Claim
32 words
A method as defined in claim 1, wherein the reaction is conducted in a reaction chamber composed of a member selected from the group consisting of pyrolytic graphite and pyrolytic boron nitride.
Claim 7
Dependent Claim
27 words
A method as defined in claim 1, wherein the final product is first flushed with an inert gas and then washed with an inert solvent for sulfur.
Claim 8
Dependent Claim
98 words
A method as defined in claim 1, wherein said substance is an oxide of a rare earth metal selected from the group consisting of Nd, Sm, Gd, Dy and Y; said gas mixture is in proportion of from about 90 percent to about 98 percent of H2S and from about 10 percent to about 2 percent of CS2; a substantial excess of the gas mixture is employed over that required to react completely with said metal reactant; and the reaction is conducted at a uniform temperature in the range of about 1,250* C to about 1, 325* C.
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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) | 1976-07-23 | 1977-01-22 | 1977-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-23 | 1981-01-22 | 1981-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-23 | 1985-01-22 | 1985-07-24 | $7700.00 | Window Closed / Lapsed |