Abstract: A method and apparatus for producing or manufacturing a high purity metallic silicon takes a process for generating silicon monoxide by causing reaction between a silicon dioxide containing material and molten state metallic silicon. The silicon monoxide thus generated is sucked for reduction by means of a reducing agent including a carbon containing material and a silicon containing material.

Abstract: Glass fibers having a low dielectric constant composed of a glass having a dielectric constant of not more than 5 and comprising:SiO.sub.2 45-65% by weight,Al.sub.2 O.sub.3 9-20% by weight,B.sub.2 O.sub.3 13-30% by weight,CaO+MgO+ZnO 4-10% by weight,Li.sub.2 O+Na.sub.2 O+K.sub.2 O 0-5% by weight,Based on the total weight of the glass, the total proportion of SiO.sub.2, Al.sub.2 O.sub.3, B.sub.2 O.sub.3, CaO, MgO, ZnO, Li.sub.2 O, Na.sub.2 O, and K.sub.2 O being at least 95% by weight.

Abstract: A process for producing silica in fine powder form, which comprises(a) adding at least one water-miscible alcohol selected from water-miscible monohydric and dihydric alcohols to an aqueous solution of an alkali metal silicate having an SiO.sub.2 concentration of 9 to 20% by weight until a solid precipitate forms and the solution begins, or is about, to become turbid,(b) adding a mineral acid to the resulting mixture in an amount 35 to 80% of the stoichiometrical amount required to neutralize the alkali metal silicate to precipitate silica as a fine powder, and(c) thereafter bringing the resulting slurry into contact with a mineral acid under an acidity of at least 1N.