Process for processing waste gases resulting during the production of silicon

US4515762A · kind A · utility

Assignee

• Wacker-Chemitronic Gesellschaft fur Elektronik Grundstoffe mbH · DE

Inventors

• Rudolf Griesshammer · Altötting, DE
• Franz Koppl · Altötting, DE
• Winfried Lang · Burghausen, DE
• Ernst Muhlhofer · Kempten (Allgäu), DE
• Michael Schwab · Neuötting, DE

Key dates

• Filing date: Nov 16, 1982
• Grant date: May 7, 1985
• Expiry date: Nov 16, 2002

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C01B33/183
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

Waste gases resulting from the production of silicon in connection with the ormation 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.sub.2. The hydrogen chloride then remaining in the gaseous phase is returned to the process stream for production of trichlorosilane.