Institute of Geology and Natural Use of Amur Science Center of Far Eastern Department of Russian Academy of Sciences (Blagoveshchensk, Russia):

Rimkevich V. S., Head of Laboratory, Candidate of Geological and Mineralogical Sciences, e-mail: vrimk@yandex.ru
Demyanova L. P., Senior Researcher, Candidate of Engineering Sciences

Nowadays, well-known types of silicon-containing raw materials are used for obtaining of ammonium hexafluosilicate, amorphous silica and amorphous silicon, which are widely applied in various branches of industry. Wide-spread silicon-containing raw materials are quartz sands, containing small quantity of harmful impurities. Objects of experimental researches are quartz sands, obtained at the time of concentration of quartz-kaolin feldspar-bearing mineral raw materials of Chalganskoe deposit (Amur Oblast). Complex processing of quartz sands was carried out by fluoride technology, using available fluorating reagent (ammonium hydrofluoride (NH₄HF₂)) with the temperature of 200 °С during 3 hours. Purification of quartz sands from harmful impurities was carried out through formation of intermediate product (ammonium hexafluosilicate ((NH₄)₂SiF₆)), which was sublimied at the temperature of 400 °С during 30–40 min. Nanoparticles of amorphous silica with high chemical purity was obtained by hydrolysis of water solution (NH₄)₂SiF₆ by ammonia water (NH₄OH). According to the data of spectral analysis, content of impurities was not more than 10–4 % (wt.). Fluorating component and ammonia water were regenerated and directed on the stages of technological process. In the time of electrolysis of water solution of ammonia hexafluosilicate, there was obtained the amorphous silicon. As a result of the carried out researches, there was developed the efficient technology of complex extraction of various science-intensive high-silicon products. Developed technology can be realized on standard experimental-industrial and industrial equipment.

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