FIELD: chemistry.
SUBSTANCE: invention relates to technology of obtaining silicon dioxide with developed specific surface and can be applied in industries which apply highly dispersed mineral filling agents. Method of obtaining highly dispersed silicon dioxide includes preliminary processing of fluoride-containing sodium metasilicate solution with calcium chloride, taken in amount 120-150% of stoichiometrically required for precipitation of fluoride-ion, at temperature 50-80°C for 0.5-1 hour, separation of calcium fluoride sediment, interaction of purified sodium metasilicate solution with compound possessing acid properties at high temperature and mixing with further filtration, washing and drying of obtained sediment. Calcium chloride is used in form of powder-like product or in form of saturated water solution. As compound with acid properties hydrochloric, sulphuric acid or carbon dioxide is used.
EFFECT: invention makes it possible to obtain highly disperse silicon dioxide with low content of fluorine admixture.
3 cl, 2 ex
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