US5021134A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of nitrogen compounds
Assignee: Tioxide Group Ltd
•
Filing: 1990-05-04
•
Granted: 1991-06-04
•
Expires: 2010-05-04
Abstract
Abstract A method for the production of a nitride of zirconium, hafnium, silicon, germanium, tin, lead, boron, aluminium, gallium, indium or thallium either alone or as mixtures is claimed. Ammonia and a halide of at least one of these elements are heated by means of a direct electric current plasma in a non-oxidizing gas in a reactor in which recirculation is induced such that the defined recirculation ratio is greater than 2.5 and preferably greater than 4.0. Any titanium halide present shall be less then 40% by weight of mixed halides.
Inventors
- 👤 Stephen R. Blackburn
- 👤 Anthony G. Jones
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 00:47
CPC Classifications
C; C01; C01B; C01B21/00; C01B21/06; C01B21/072; C01B21/0602; C01B21/0632; C01B21/0635; C01B21/064; C01B21/068; C01B21/076; C01B21/0763; C01P; C01P2006/00; C01P2006/10; C01P2006/12
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
194 words
A method for the manufacture of a nitride comprising heating ammonia and a halide selected from the class consisting of halides of zirconium, hafnium, silicon, germanium, tin, lead, boron, aluminium gallium, indium and thallium and mixtures of said halides containing less than 40% by weight of a titanium halide to a chosen reaction temperature by means of an electric plasma formed in a stream of a non-oxidizing gas generated by the discharge of direct current electricity between a pair of electrodes, introducing said heated gas through an inlet nozzle into a reactor and said reactor being so constructed and operated as to induce circulation of gaseous material in the reactor such that the recirculation ratio (RR) is greater than 2.5 and collecting a nitride powder in which method the recirculation ratio is defined according to the formula ##EQU2## wherein Mn=mass flow of gas stream through inlet nozzle R=internal radius of the reactor into which said nozzle flows M=mass flow at a distance 4R downstream from the inlet nozzle Rn=radius of inlet nozzle Dn=density of gas stream passing through inlet nozzle D=density of gases in reactor at a distance 4R downstream from the inlet nozzle.
Claim 2
Independent Claim
194 words
A method for the manufacture of a nitride comprising heating ammonia and a halide selected from the class consisting of halides of zirconium, hafnium, silicon, germanium, tin, lead, boron, aluminium gallium, indium and thallium and mixtures of said halides containing less than 40% by weight of a titanium halide to a chosen reaction temperature by means of an electric plasma formed in a stream of a non-oxidizing gas generated by the discharge of direct current electricity between a pair of electrodes, introducing said heated gas through an inlet nozzle into a reactor and said reactor being so constructed and operated as to induce circulation of gaseous material in the reactor such that the recirculation ratio (RR) is greater than 2.5 and collecting a nitride powder in which method the recirculation ratio is defined according to the formula ##EQU2## wherein Mn=mass flow of gas stream through inlet nozzle R=internal radius of the reactor into which said nozzle flows M=mass flow at a distance 4R downstream from the inlet nozzle Rn=radius of inlet nozzle Dn=density of gas stream passing through inlet nozzle D=density of gases in reactor at a distance 4R downstream from the inlet nozzle.
Claim 3
Dependent Claim
15 words
A method according to claim 1 in which the recirculation ratio is greater than 4.
Claim 4
Dependent Claim
35 words
A method according to claim 1 in which the concentration of the halide or halides without considering reaction or dissociation lies in the range 3 to 30 molar per cent of the total gas stream.
Claim 5
Dependent Claim
24 words
A method according to claim 3 in which said concentration of halide or halides lies in the range 3 to 20 molar per cent.
Claim 6
Dependent Claim
24 words
A method according to claim 3 in which said concentration of halide or halides lies in the range 4.5 to 15 molar per cent.
Claim 7
Dependent Claim
28 words
A method according to claim 1 in which the net power provided in the said plasma is from 50 to 500 kcals per minute per mole of halide.
Claim 8
Dependent Claim
32 words
A method according to claim 1 in which the direct current electricity has an amperage of from 80 amps to 600 amps and a voltage of from 25 volts to 250 volts.
Claim 9
Dependent Claim
30 words
A method according to claim 1 in which at least one halide is selected from the class consisting of silicon tetrachloride, aluminium trichloride, boron trifluoride, zirconium tetrachloride and tin tetrachloride.
Claim 10
Dependent Claim
18 words
A method according to claim 1 in which the mixture of halide is substantially free of titanium halide.
Claim 11
Dependent Claim
29 words
A method according to claim 1 in which the halide or mixture of halides is introduced into the reactor at a rate of 0.1 to 5.0 mole per minute.
Claim 12
Dependent Claim
25 words
A method according to claim 1 in which the ammonia is introduced into the reactor at a rate of 0.2 to 50 mole per minute.
Claim 13
Dependent Claim
16 words
A method according to claim 1 in which the non-oxidizing gas is argon, nitrogen or hydrogen.
Claim 14
Dependent Claim
23 words
A method according to claim 1 in which more than one halide is used and the halides are separately added to the reactor.
Claim 15
Dependent Claim
25 words
A method according to claim 1 in which the nitride powder is collected by deposition in hydrochloric acid solution containing up to 20% hydrochloric acid.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-06-03 | 1994-12-03 | 1995-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-06-03 | 1998-12-03 | 1999-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-06-03 | 2002-12-03 | 2003-06-04 | $7700.00 | Window Closed / Lapsed |