Patent US4642228A successfully refreshed from Google Patents.
US4642228A
Expired / Lapsed
US
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Fluxing system for reactors for production of silicon
Assignee: Enichem SpA
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Filing: 1985-07-24
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Granted: 1987-02-10
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Expires: 2005-07-24
Abstract
Abstract A process is disclosed for the production of elemental silicon that utilizes a non-reactive condensible gas as a means for purging the reactor of ambient air prior to the introduction of an alkali metal and a silicon tetrahalide.
Inventors
- 👤 Angel Sanjurjo
- 👤 Kenneth M. Sancier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 08:19
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/02; C01B33/021; C01B33/027; C01B33/033
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
112 words
A process for the production of substantially pure elemental silicon said process comprising the steps of: (a) passing a halogenated hydrocarbon gas containing one or more fluorine atoms that is condensible from -90° C. to +50° C. at atomspheric pressure into a reaction zone for use in the production of elemental silicon, through the reduction of the corresponding gaseous halide by means of an elemental alkali metal; (b) passing a silicon tetrahalide into said reaction zone to displace said condensible halogenated hydrocarbon gas; (c) passing an alkali metal into said reaction zone to obtain a mixture of silicon and an alkali metal halide; and (d) separating substantially pure silicon from said mixture.
Claim 2
Dependent Claim
112 words
A process for the production of substantially pure elemental silicon said process comprising the steps of: (a) passing a halogenated hydrocarbon gas containing one or more fluorine atoms that is condensible from -90° C. to +50° C. at atomspheric pressure into a reaction zone for use in the production of elemental silicon, through the reduction of the corresponding gaseous halide by means of an elemental alkali metal; (b) passing a silicon tetrahalide into said reaction zone to displace said condensible halogenated hydrocarbon gas; (c) passing an alkali metal into said reaction zone to obtain a mixture of silicon and an alkali metal halide; and (d) separating substantially pure silicon from said mixture.
Claim 3
Dependent Claim
38 words
A process as defined in claim 1 wherein elemental silicon is produced and the halogenated hydrocarbon gas containing one or more fluorine atoms is selected from the group consisting of dichlorodifluoromethane, bromotrifluoromethane, dibromodifluoromethane, 1,1,2-trichloro-1,2,2,-trifluoroethane, 1,2-dichloro-1,1,2,2,-tetrafluoroethane and mixtures thereof.
Claim 4
Dependent Claim
21 words
A process for the production of substantially pure silicon, as defined in claim 2 wherein the silicon tetrahalide is silicon tetrafluoride.
Claim 5
Dependent Claim
20 words
A process for the production of substantially pure silicon as defined in claim 3 wherein the alkali metal is sodium.
Claim 6
Dependent Claim
27 words
A process for the production of substantially pure silicon as defined in claim 4 wherein the halogenated hydrocarbon gas containing at least one fluorine atom is dichlorodifluoromethane.
Claim 7
Dependent Claim
48 words
A process for the production of substantially pure silicon as defined in claim 1 wherein the process comprises a further step wherein the halogenated hydrocarbon gas containing one or more fluorine atom is condensed, after it is displaced by the silicon tetrahalide, and recycled to the reaction zone.
Claim 8
Dependent Claim
41 words
A process for the production of substantially pure silicon as defined in claim 6 wherein ambient air is separated from the halogenated gas containing one or more fluorine atoms and said ambient air is vented to the atmosphere through a scrubber.
Claim 9
Dependent Claim
44 words
A process for the production of substantially pure silicon as defined in claim 7 wherein after the reaction is terminated, an inert gas is passed into the reactor to remove any unreacted silicon tetrafluoride as a mixture of inert gas and unreacted silicon tetrafluoride.
Claim 10
Dependent Claim
33 words
A process for the production of substantially pure silicon as defined in claim 8 wherein the unreacted silicon tetrafluoride is separated from the mixture of inert gas and silicon tetrahalide in a condenser.
Claim 11
Dependent Claim
36 words
A process for the production of substantially pure silicon as defined in claim 9 wherein the unreacted silicon tetrafluoride that is condensed from the mixture of inert gas and silicon tetrafluoride, is recycled to the reactor.
References Cited (Backward Citations)
US4442082A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-02-09 | 1990-08-11 | 1991-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-09 | 1994-08-11 | 1995-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-09 | 1998-08-11 | 1999-02-10 | $7700.00 | Window Closed / Lapsed |