GB1462579A - Production of highly dispersed silicon dioxide - Google Patents

Abstract

1462579 Highly disperse silica LONZA Ltd 22 July 1975 [26 July 1974] 30604/75 Heading C1A [Also in Division F4] In a process for the production of highly dispersed silicon dioxide by the reaction of a material consisting of or containing silicon dioxide with a reducing agent at an elevated temperature with the formation of a silicon monoxide-containing gas stream, subsequent cooling of the gas stream in the presence of an oxidising gas and separation from the residual gas of the highly dispersed silicon dioxide resulting by cooling, a stream of hot gas from a plasma burner is passed axially into a hollow cylindrically-shaped chamber arranged horizontally with openings in both end faces thereof in the axis of rotation, said hollow cylindrically-shaped chamber being rotated about its longitudinal axis, material consisting of or containing silicon dioxide is introduced at the burner end of the rotating hollow cylindrically-shaped chamber and impelled by the centrifugal force on to the inner walls of said chamber and thereby melted and reduced to silicon monoxide which evaporates from the melt into the gas stream, the gas stream, which contains silicon monoxide and entrained particles of silicon dioxide, is subsequently introduced tangentially through an inlet into one side of at least one further non- rotating hollow cylindrically-shaped chamber arranged vertically to the longitudinal axis of the rotating chamber so that a whirling movement results and complete reaction of the entrained silicon dioxide takes place, the gas stream is allowed to flow from the reactor through at least one tangential outlet on the side of the non-rotating hollow cylindricallyshaped chamber, the outlet being above or below and on the opposite side to the inlet, whereafter the gas stream is quenched and re-oxidized.