Patent attributes
An economic process for producing high quality finely divided silicon dioxide from mixtures comprising economical silicon compounds without operational disturbances is characterized by using as an Si source mixture of at least two silicon compounds, at least one being carbon-containing and at least one being carbon-free, supplying a fuel gas and an oxygen-containing source, the molar C/Si ratio of this mixture being between 10/BET and 35/BET, and the molar H/Cl ratio of this mixture being between 0.45+(BET/600) and 0.95+(BET/600), with BET being the specific surface area of the pyrogenic silicon dioxide under production, introducing this mixture as the main flow into a reaction space and igniting and reacting it, and isolating the resulting solid.