US4515762A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for processing waste gases resulting during the production of silicon
Assignee: Wacker Chemie AG
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Filing: 1982-11-16
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Granted: 1985-05-07
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Expires: 2002-11-16
Abstract
Abstract Waste gases resulting from the production of silicon in connection with theormation or decomposition of chlorosilanes, which gases always contain hydrogen chloride, can be worked up without removal of the hydrogen chloride. For this purpose, the waste gases which, after separation from the chlorosilanes, only contain hydrogen and hydrogen chloride, are subjected to combustion with addition of air and, after addition of silicon tetrachloride, the result being highly dispersed SiO 2 . The hydrogen chloride then remaining in the gaseous phase is returned to the process stream for production of trichlorosilane.
Inventors
- 👤 Rudolf Griesshammer
- 👤 Franz Koppl
- 👤 Winfried Lang
- 👤 Ernst Muhlhofer
- 👤 Michael Schwab
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:07
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/68; C; C01; C01B; C01B13/00; C01B13/14; C01B13/20; C01B13/22; C01B33/00; C01B33/02; C01B33/021; C01B33/027; C01B33/035; C01B33/08; C01B33/107; C01B33/1071; C01B33/10742; C01B33/10757; C01B33/113; C01B33/12; C01B33/18; C01B33/181; C01B33/183
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
98 words
A process for processing waste gases comprising a gas mixture including chlorosilanes, hydrogen and hydrogen chloride, comprising the steps of: (a) removing the chlorosilanes contained in the waste gas mixture by condensation; (b) adding to the remaining gas mixture an oxygen-containing gas; (c) adding at least one chloride selected from the group consisting of germanium chloride, titanium chloride and silicon tetrachloride to the gas mixture resulting from step (b) and subjecting the same to combustion for the pyrogenic formation of oxide particles; and (d) recovering the hydrogen chloride remaining in the gas mixture following step (c) for reuse.
Claim 2
Dependent Claim
98 words
A process for processing waste gases comprising a gas mixture including chlorosilanes, hydrogen and hydrogen chloride, comprising the steps of: (a) removing the chlorosilanes contained in the waste gas mixture by condensation; (b) adding to the remaining gas mixture an oxygen-containing gas; (c) adding at least one chloride selected from the group consisting of germanium chloride, titanium chloride and silicon tetrachloride to the gas mixture resulting from step (b) and subjecting the same to combustion for the pyrogenic formation of oxide particles; and (d) recovering the hydrogen chloride remaining in the gas mixture following step (c) for reuse.
Claim 3
Dependent Claim
31 words
The process according to claim 1, wherein to the gas mixture formed in step (b) silicon tetrachloride is added for the pyrogenic formation of highly dispersed SiO 2 in step (c).
Claim 4
Dependent Claim
16 words
The process according to claim 1, wherein the oxygen-containing gas added in step (b) is air.
Claim 5
Dependent Claim
22 words
The process according to claim 1, wherein said recovered hydrogen chloride is returned to a process stream for the production of trichlorosilane.
References Cited (Backward Citations)
DE149054C
Cited
US3954945A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-05-06 | 1988-11-05 | 1989-05-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-06 | 1992-11-05 | 1993-05-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-06 | 1996-11-05 | 1997-05-07 | $7700.00 | Window Closed / Lapsed |