US3976749A
Expired / Lapsed
US
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Method for producing pure monocarbides, mononitrides and carbonitrides
Assignee: Gesellschaft fuer Kernforschung mbH
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Filing: 1973-12-21
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Granted: 1976-08-24
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Expires: 1993-12-21
Abstract
Abstract Pure monocarbides, or pure mononitrides or carbonitrides of metals are prepared by first forming a mixture of carbon with an oxalate of the metals and thermally decomposing the metal oxalate in the presence of the carbon by a stream of hydrogen. The hydrogen is removed and monocarbides are then formed by heating the decomposition products in vacuo to carbothermally reduce them. Mononitrides and carbonitrides can be formed by replacing the hydrogen with nitrogen and heating the decomposition products in the nitrogen.
Inventors
- 👤 Horst Wedemeyer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 07:53
CPC Classifications
G; G21; G21C; G21C3/00; G21C3/42; G21C3/58; G21C3/62; C; C01; C01B; C01B21/00; C01B21/06; C01B21/0615; C01B21/063; C01B21/082; C01B21/0828; C01B32/00; C01B32/90; C01B21/0617; C01B21/062; C01B21/076; C01P; C01P2006/00; C01P2006/80; Y; Y02; Y02E; Y02E30/00; Y02E30/30
Claims Analysis
Total Claims: 43
Claim 1
Independent Claim
101 words
A method of producing pure monocarbides of at least one of the metals titanium, vanadium, zirconium, niobium, molybdenum, hafnium, tantalum, tungsten, thorium, uranium, plutonium, or americium comprising: a. forming a mixture of carbon with an oxalate of at least one of said metals; b. decomposing the metal oxalate in the presence of carbon in a stream of a hydrogen containing gas with addition of heat; c. removing the hydrogen containing gas; and d. heating the decomposition products immediately after removal of the hydrogen containing gas to an elevated temperature in vacuo to carbothermally reduce the decomposition products and from the monocarbide.
Claim 2
Independent Claim
101 words
A method of producing pure monocarbides of at least one of the metals titanium, vanadium, zirconium, niobium, molybdenum, hafnium, tantalum, tungsten, thorium, uranium, plutonium, or americium comprising: a. forming a mixture of carbon with an oxalate of at least one of said metals; b. decomposing the metal oxalate in the presence of carbon in a stream of a hydrogen containing gas with addition of heat; c. removing the hydrogen containing gas; and d. heating the decomposition products immediately after removal of the hydrogen containing gas to an elevated temperature in vacuo to carbothermally reduce the decomposition products and from the monocarbide.
Claim 3
Dependent Claim
30 words
The method according to claim 1 wherein the metal oxalate is uranyl oxalate which is decomposed to UO 2 having a stoichiometric 2 to 1 ratio of oxygen to uranium.
Claim 4
Dependent Claim
27 words
The method according to claim 2 wherein the uranyl oxalate is mixed with carbon at a mole ratio of UO 2 to carbon of 1 to 3.
Claim 5
Dependent Claim
20 words
The method according to claim 2 wherein the carbothermal reduction takes place at a temperature between about 1100°C and 1300°C.
Claim 6
Dependent Claim
30 words
The method according to claim 1 wherein the metal oxalate is plutonium oxalate which is decomposed to plutonium dioxide having a stoichiometric 2 to 1 ratio of oxygen to plutonium.
Claim 7
Dependent Claim
27 words
The method according to claim 5 wherein the plutonium oxalate is mixed with carbon at a mole ratio of PuO 2 to carbon of 1 to 3.
Claim 8
Dependent Claim
30 words
The method according to claim 1 including converting at least one of said metals to its oxalate, purifying the oxalate, and forming a homogeneous mixture of the oxalate with carbon.
Claim 9
Dependent Claim
38 words
The method according to claim 7 wherein uranyl and/or plutonium oxalates are formed in an aqueous solution containing uranium and/or plutonium by addition of oxalate ions, and the resulting metal oxalates are separated from the solution and dried.
Claim 10
Dependent Claim
40 words
The method according to claim 8 wherein the aqueous solution contains nitrate ions, and the oxalates are crystal hydrates which are separated from the solution, rinsed, and dried and freed from impurities in vacuo before they are mixed with carbon.
Claim 11
Dependent Claim
48 words
The method according to claim 9 wherein the metal oxalate crystals are decomposed in a reaction furnace at a temperature of more than 600°C in a stream of hydrogen or a stream of hydrogen and an inert gas, and the reaction furnace is evacuated immediately after the decomposition.
Claim 12
Dependent Claim
33 words
The method according to claim 10 wherein the carbothermal reduction occurs immediately after removal of the hydrogen containing gas while maintaining a vacuum in a temperature range between about 1100° and about 1300°C.
Claim 13
Dependent Claim
26 words
The method according to claim 8 wherein the metal oxalate is mixed with carbon at a mole ratio of metaloxide to carbon of 1 to 3.
Claim 14
Dependent Claim
25 words
The method according to claim 10 wherein the decomposition of the metal oxalate takes place at a maximum temperature between about 750° and about 800°C.
Claim 15
Dependent Claim
19 words
The method according to claim 11 wherein the carbothermal reduction takes place at a temperature of 1250° to 1300°C.
Claim 16
Independent Claim
103 words
A method for producing pure mononitrides or carbonitrides of at least one of the metals titanium, vanadium, zirconium, niobium, molybdenum, hafnium, tantalum, tungsten, thorium, uranium, plutonium, or americium, comprising: a. forming a mixture of carbon with an oxalate of at least one of said metals; b. decomposing the metal oxalate in the presence of carbon in a stream of a hydrogen containing gas with the addition of heat; c. removing the hydrogen containing gas and feeding a nitrogen stream into contact with the decomposition products; and d. heating the decomposition products immediately after removal of the hydrogen containing gas in the nitrogen stream.
Claim 17
Independent Claim
103 words
A method for producing pure mononitrides or carbonitrides of at least one of the metals titanium, vanadium, zirconium, niobium, molybdenum, hafnium, tantalum, tungsten, thorium, uranium, plutonium, or americium, comprising: a. forming a mixture of carbon with an oxalate of at least one of said metals; b. decomposing the metal oxalate in the presence of carbon in a stream of a hydrogen containing gas with the addition of heat; c. removing the hydrogen containing gas and feeding a nitrogen stream into contact with the decomposition products; and d. heating the decomposition products immediately after removal of the hydrogen containing gas in the nitrogen stream.
Claim 18
Dependent Claim
30 words
The method according to claim 15 wherein the metal oxalate is mixed with carbon at a mole ratio of metaloxide to carbon of 1 to 2 to produce pure mononitrides.
Claim 19
Dependent Claim
21 words
The method according to claim 16 wherein the decomposition products are heated with the nitrogen at a temperature greater than 1500°C.
Claim 20
Dependent Claim
45 words
The method according to claim 16 wherein the decomposition products are heated with the nitrogen in a reaction furnace at a temperature of about 1750° to about 1800°C until the CO content of the nitrogen flowing out of the furnace is less than 2ppm CO.
Claim 21
Dependent Claim
48 words
The method according to claim 15 wherein pure carbonitrides are produced by mixing the metal oxalate with carbon at a mole ratio of metaloxide to carbon between 1 to 2 and 1 to 3 and the decomposition products are heated with nitrogen at a temperature of about 1500°C.
Claim 22
Dependent Claim
31 words
The method according to claim 15 wherein the stream of nitrogen consists of nitrogen alone or of a mixture of nitrogen and a gas which is inert under the reaction conditions.
Claim 23
Dependent Claim
30 words
The method according to claim 15 wherein the metal oxalate is uranyl oxalate which is decomposed to UO 2 having a stoichiometric 2 to 1 ratio of oxygen to uranium.
Claim 24
Dependent Claim
42 words
The method according to claim 21 wherein the uranyl oxalate is mixed with carbon at a mole ratio of UO 2 to carbon of 1 to 2 and the decomposition products are heated with nitrogen at a temperature of more than 1500°C.
Claim 25
Dependent Claim
30 words
The method according to claim 15 wherein the metal oxalate is plutonium oxalate which is decomposed to plutonium dioxide having a stoichiometric 2 to 1 ratio of oxygen to plutonium.
Claim 26
Dependent Claim
42 words
The method according to claim 23 wherein the plutonium oxalate is mixed with carbon at a mole ratio of PuO 2 to carbon of 1 to 2 and the decomposition products are heated with nitrogen at a temperature of more than 1500°C.
Claim 27
Dependent Claim
30 words
The method according to claim 15 including converting at least one of said metals to its oxalate, purifying the oxalate, and forming a homogeneous mixture of the oxalate with carbon.
Claim 28
Dependent Claim
38 words
The method according to claim 25 wherein uranyl and/or plutonium oxalates are formed in an aqueous solution containing uranium and/or plutonium by addition of oxalate ions, and the resulting metal oxalates are separated from the solution and dried.
Claim 29
Dependent Claim
40 words
The method according to claim 26 wherein the aqueous solution contains nitrate ions, and the oxalates are crystal hydrates which are separated from the solution, rinsed and dried and freed from impurities in vacuo before they are mixed with carbon.
Claim 30
Dependent Claim
38 words
The method according to claim 27 wherein the metal oxalate crystals are decomposed in a reaction furnace at a temperature of more than 600°C in a stream of hydrogen or a stream of hydrogen and an inert gas.
Claim 31
Dependent Claim
37 words
The method according to claim 28 wherein a single-phase mononitride is produced and the decomposition products are heated to a temperature of more than 1500°C in the nitrogen stream until the formation of carbon monoxide is completed.
Claim 32
Dependent Claim
39 words
The method according to claim 29 wherein after the formation of carbon monoxide is completed, the resulting singlephase mononitride is initially cooled in a stream of nitrogen to about 1350°C and then is cooled to room temperature in vacuo.
Claim 33
Dependent Claim
30 words
The method according to claim 25 wherein the oxalate crystals are mixed with carbon at a mole ratio of metaloxide to carbon of 1 to 2 to produce pure mononitrides.
Claim 34
Dependent Claim
25 words
The method according to claim 28 wherein the decomposition of the metal oxalate takes place at a maximum temperature between about 750° and about 800°C.
Claim 35
Dependent Claim
40 words
The method according to claim 29 wherein the heating of the decomposition products in the stream of nitrogen occurs at 1750° to 1800°C until the CO content of the nitrogen flowing out of the furnace is less than 2ppm CO.
Claim 36
Dependent Claim
49 words
The method according to claim 25 wherein pure carbonitrides are produced by mixing the metal oxalate with carbon at a mole ratio of metaloxide to carbon, between 1 to 2 and 1 to 3 and the decomposition products are heated with a nitrogen at a temperature of about 1500°C.
Claim 37
Dependent Claim
31 words
The method according to claim 25 wherein the stream of nitrogen consists of nitrogen alone or of a mixture of nitrogen and a gas which is inert under the reaction conditions.
Claim 38
Independent Claim
121 words
A method for producing pure monocarbides of at least one of the metals titanium, vanadium, zirconium, niobium, molybdenum, hafnium, tantalum, tungsten, thorium, uranium, plutonium, or americium, comprising: a. converting at least one of the metals to its oxalate; b. cleaning the oxalate; c. forming a homogeneous mixture of the oxalate with carbon; d. decomposing the oxalate in the presence of carbon in a stream of hydrogen or in a stream of a mixture of hydrogen and an inert gas with the addition of heat; e. removing the hydrogen containing stream; and f. heating the decomposition products in vacuo in a multi-stage heat treatment immediately after removal of the hydrogen containing stream to carbothermally reduce the decomposition products and form the monocarbide.
Claim 39
Independent Claim
121 words
A method for producing pure monocarbides of at least one of the metals titanium, vanadium, zirconium, niobium, molybdenum, hafnium, tantalum, tungsten, thorium, uranium, plutonium, or americium, comprising: a. converting at least one of the metals to its oxalate; b. cleaning the oxalate; c. forming a homogeneous mixture of the oxalate with carbon; d. decomposing the oxalate in the presence of carbon in a stream of hydrogen or in a stream of a mixture of hydrogen and an inert gas with the addition of heat; e. removing the hydrogen containing stream; and f. heating the decomposition products in vacuo in a multi-stage heat treatment immediately after removal of the hydrogen containing stream to carbothermally reduce the decomposition products and form the monocarbide.
Claim 40
Dependent Claim
43 words
The method according to claim 36 wherein a monocarbide useful as a high output nuclear fuel is prepared by mixing an aqueous solution of uranium and/or plutonium compounds with oxalate ions, and the resulting oxalate precipitate is separated from the solution, and dried.
Claim 41
Independent Claim
113 words
A method for producing pure mononitrides or carbonitrides of at least one of the metals titanium, vanadium, zirconium, niobium, molybdenum, hafnium, tantalum, tungsten, thorium, uranium, plutonium or americium comprising: a. converting at least one of the metals to its oxalate; b. cleaning the oxalate; c. forming a homogeneous mixture of the oxalate with carbon; d. decomposing the oxalate in the presence of carbon in a stream of hydrogen or in a stream of hydrogen and an inert gas with the addition of heat; e. removing the hydrogen containing stream; and f. heating the decomposition products immediately after removal of the hydrogen containing stream in the stream of nitrogen in a multi-stage heat treatment.
Claim 42
Independent Claim
113 words
A method for producing pure mononitrides or carbonitrides of at least one of the metals titanium, vanadium, zirconium, niobium, molybdenum, hafnium, tantalum, tungsten, thorium, uranium, plutonium or americium comprising: a. converting at least one of the metals to its oxalate; b. cleaning the oxalate; c. forming a homogeneous mixture of the oxalate with carbon; d. decomposing the oxalate in the presence of carbon in a stream of hydrogen or in a stream of hydrogen and an inert gas with the addition of heat; e. removing the hydrogen containing stream; and f. heating the decomposition products immediately after removal of the hydrogen containing stream in the stream of nitrogen in a multi-stage heat treatment.
Claim 43
Dependent Claim
42 words
The method according to claim 38 wherein a mononitride useful as a high output nuclear fuel is prepared by mixing aqueous solutions of uranium and/or plutonium compounds with oxalate ions, and the resulting oxalate precipitate is separated from the solution and dried.
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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) | 1979-08-24 | 1980-02-23 | 1980-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-24 | 1984-02-23 | 1984-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-24 | 1988-02-23 | 1988-08-24 | $7700.00 | Window Closed / Lapsed |