HIGH PURITY SYNTHETIC FLUORITE, METHOD OF ITS PRODUCTION AND INSTALLATION FOR IMPLEMENTATION OF METHOD

摘要

FIELD: chemical industry.;SUBSTANCE: method of producing synthetic fluorite CaF₂ involves preparing NH₄F solution by basic hydrolysis of fluorosilicic acid H₂SiF₆ with aqueous NH₃ solution. Said NH₄F solution is filtered to form a substantially silica-free aqueous NH₄F solution. Filtered NH₄F solution is treated with calcium hydroxide taken in excessive amount to form a dispersion. Alternatively, filtered NH₄F solution can be treated with calcium carbonate taken in excessive amount to form a dispersion. One more alternative is distillation of NH₄F solution obtained after filtration at low pressure in order to convert ammonium fluoride into ammonium bifluoride. Then obtained ammonium bifluoride is reacted with calcium carbonate or with calcium hydroxide. Solution obtained as a result of the above steps is filtered to obtain synthetic fluorite in the form of a suspension having a moisture content of 30–50 wt %. Suspension is dried and granulated to form synthetic fluorite CaF₂ of acid grade in form of granules. At least 50 % of these granules have average size of more than 1 mm.;EFFECT: invention enables to obtain high-purity synthetic fluorite with low content of SiO₂, MgO and high output.;12 cl, 8 dwg, 5 tbl