Verfahren und Vorrichtung zur Reinigung von Silan enthaltenden Gasen

Die Erfindung betrifft ein Verfahren und eine Vorrichtung zur Verringerung des Gehalts an Silan bzw. dessen vollstaendige Entfernung aus Gasen und Fluessigkeiten, insbesondere aus Abgasstroemen, durch Kontaktieren mit einer Natriumhypochlorit enthaltenden Loesung. Eine zuverlaessige Verringerung oder Entfernung des Gehalts an Silan unter wirtschaftlich guenstigen Bedingungen und mit einer moeglichen Wiederverwertbarkeit des entfernten Silans wird dadurch erreicht, dass als Loesung eine Natriumhypochlorit und Natronlauge enthaltende, alkalische, waessrige Loesung verwendet wird.

DE 10053345 A UPAB: 20020711 NOVELTY - Reduction or removal of the content of silane from gases, especially waste gases, by contact with a solution containing sodium hypochlorite (NaOCl) uses an alkaline aqueous solution containing NaOCl and aqueous sodium hydroxide (NaOH) solution. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for (1) Aqueous alkaline NaOCl solution containing NaOH for use in this process, produced by mixing aqueous NaOH solution and aqueous NaOCl solution during or before the reaction, optionally with addition of water; (2) Apparatus with a packed column for operating the process. USE - The reaction product is used for the production of precipitated silica or silica sol, which is free from metals and low in impurities (all claimed). The process is useful in the production of silane and of very pure silicon from silane. ADVANTAGE - Silane, which is spontaneously flammable, can be removed from gas streams by combustion or hydrolysis, especially alkaline hydrolysis. The first gives waste silica dust or dilute silicate solution, whilst the second is slow, requires large apparatus and large amounts of circulating solution and gives hydrogen, which forms explosive mixtures with air. The present process is reliable and cost-effective and gives a useful product. It is suitable for continuous or batch operation.