Growing demand for fluorinating reagents to be used in rare-metal industry has stimulated conducting research in the field of production for these reagents. That is why the fluorinating reagents production has recently formed an independent segment of industry. Main industrial fluorinating reagents include hydrofluoric acid, anhydrous hydrogen fluoride, technical ammonium hydrodifluoride, fluorosilicic acid and its salts. To produce technical etching acid, fluor-spar with calcium fluoride content at least 92% is used in most cases. To produce anhydrous hydrogen fluoride, fluor-spar with calcium fluoride content 96%-97% is necessary. The fluorine-containing raw materials refinement from silica by means of flotation makes the fluorinating reagents production substantially more expensive. In this work we have attempted to process unconcentrated raw materials by fluorine removal in the form of volatile silicon tetrafluoride. In this process silicon tetrafluoride was recovered by liquid ammonia with subsequent hydrolysis of the formed ammonia hexafluorosilicate. Hydrolysis occurred according to the reaction:(NH_4)_2SiF_6+4NH_3+2H_2O=6NH_4F+SiO_2The products of the ammonia hexafluorosilicate hydrolysis included ammonia fluoride and amorphous silica gel (“white soot”) as by-product. This “white soot” was of high purity-with main component content 99.95% and total admixture content 0.05%. Silica gel is a superfine material with specific surface of 267.6 m~2/g and is recommended as filler in the production of rubber, plastics and for other applications. Ammonia fluoride was transformed into ammonia hydrodifluoride (main processing product) according to the reaction:2NH_4F→NH_3+NH_4HF_2It was stated that the NH_4F:NH_4HF_2 ratio depends on boiling point temperature-with its increase the ammonia hydrofluoride concentration in solution increases as well. Growing demand for fluorinating reagents to be used in rare-metal industry has stimulated conducting research in the field of production for these reagents. anhydrous hydrogen fluoride, technical ammonium hydrodifluoride, fluorosilicic acid and its salts. To produce technical etching acid, fluor-spar with calcium fluoride content at least 92% is used in most cases. 96% -97% is necessary. The fluorine-containing raw materials refinement from silica by means of flotation make the fluorinating reagents production substantially more expensive. In this work we have attempted to process unconcentrated raw materials by fluorine removal in the form of volatile silicon tetrafluoride. In this process silicon tetrafluoride was recovered by liquid amm onia with subsequent hydrolysis of the formed ammonia hexafluorosilicate. [0004] The present invention relates to the use of ammonia hexafluorosilicate (see “white soot”) as by (NH_4) _2SiF_6 + 4NH_3 + 2H_2O = 6NH_4F + SiO_2The products of the ammonia hexafluorosilicate hydrolysis include ammonia fluoride and amorphous silica gel -product. This “white soot” was of high purity-with main component content of 99.95% and total admixture content of 0.05%. Silica gel is a superfine material with specific surface of 267.6 m ~ 2 / g and is recommended as filler in the production of rubber, plastics and other for applications. Ammonia fluoride was transformed into ammonia hydrodifluoride (main processing product) according to the reaction: 2NH_4F → NH_3 + NH_4HF_2It was stated that the NH_4F: NH_4HF_2 ratio depends on boiling point temperature-with its increase the ammonia hydrofluoride concentration in solution increases as well.