Abstract: An improved process for contacting hydrogen gas and tetrachlorosilane in a reactor comprising a pressurizable shell having located therein a reaction vessel forming a substantially closed inner chamber for reacting the hydrogen gas with the tetrachlorosilane. The improvement comprises feeding to an outer chamber between the pressurizable shell and the reaction vessel a gas or gaseous mixture having a chlorine to silicon molar ratio greater than about 3.5. The improvement reduces the concentration of hydrogen and tetrachlorosilane in the outer chamber that results from leakage of these gases from the substantially closed inner chamber and the detrimental reactions associated with such leakage on structural elements and performance of the reactor.

Abstract: A process for recovering chlorine present in a gaseous vent stream. The process comprises contacting a gaseous vent gas comprising hydrogen chloride and a hydrosilane with a chlorination catalyst to form a more chlorinated silane. The chlorination of the hydrosilane captures the chlorine of the hydrogen chloride as a substituent of the resulting chlorosilane and provides for a readily condensable chlorosilane.

Abstract: The present invention relates to an insulation system for a high temperature reactor in which chlorosilanes and hydrogen gases are present. The system described comprises an inner graphite radiant heat shield and an outer carbon-based, rigid, felt insulation of high density. The inner radient heat shield provides increased chemical stability at the hot face in a chlorosilane and hydrogen reactor. Also, the inner radient heat shield reduces the temperature at the interface with the carbon-based rigid felt, thereby reducing the reactivity of the chlorosilanes with the carbon-based rigid felt. The high density of the carbon-based rigid belt further reduces radiant heat loss. More importantly, the high density of the carbon-based rigid felt excludes the highly heat conductive hydrogen gas from the voids of the flet. The insulation system, as described, allows reactors containing chlorosilanes and hydrogen gases to be operated at higher and more efficient temperatures for longer periods of time.

Abstract: The present invention is a process for separating particulate silicon from a liquid by-product stream containing silanes. The liquid by-product stream comprising silanes and particulate silicon is atomized into a heated zone to effect vaporization of the liquid silanes, thus drying the particulate silicon. The dried particulate silicon is separated from the gaseous silanes by filtration or other suitable means. The separated solid and gaseous phases may be used as feed to the process generating the by-product stream or as a feed for other processes.