Process for producing ammonium silicofluoride or silica.

摘要

A process for producing ammonium silicofluoride which comprises: (1) reacting a crude silica with ammonium fluoride, acid ammonium fluoride or a mixture thereof in an aqueous medium to produce ammonium silicofluoride, and (2) separating the ammonium silicofluoride from the unreacted silica and impurities by means of a solid/liquid separation, and optionally, reacting the separated ammonium silicofluoride with ammonia in an aqueous medium. n