METHOD OF OBTAINING SODIUM SILICON FLUORIDE Russian patent published in 2009 - IPC C01B33/10 

FIELD: chemistry.

SUBSTANCE: present invention relates to chemical industry. Fluorine-containing gas from wet-process production of phosphoric acid and fertiliser are absorbed by water. The obtained hydrofluosilicic acid is neutralised with soda at pH 0.2-3.0 for a period of 0.25-1 h. The obtained crystals are settled and the thick pulp is dried in fluid-bed furnaces. The dried product is separated on sieves or centrifugal collector with separation of fractions with particle size more than 0.1 mm. The fine fraction with particle size less than 0.1 mm is the end product.

EFFECT: treatment of hydrofluosilicic acid, contaminated with silicon dioxide impurities, into a quality end product with high content basic substance Na₂SiF₆.

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