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MAGNESIUM, TITANIUM, RARE METALS, SEMICONDUCTORS
ArticleName Utilization of silica in wastes of silicon semiconductor
ArticleAuthor Pochtaryev A. N., Kozhemyakin V. A., Antipova N. V.
ArticleAuthorData

OJSC “Giredmet”, Moscow, Russia:

A. N. Pochtarуev, Head of Laboratory, e-mail: ANP1945@mail.ru
V. A. Kozhemyakin, Leading Researcher
N. V. Antipova, Researcher

Abstract

Results of laboratory researches of absorption chlorsilines by a solution caustic alkali are presented. Vent gases (an air plus chlorsilines: mixture vapors of threechlorsiline and tetrachlorsiline) in a vessel (barboter) with the solution caustic aikali are feeded. Contents of chlorsilines in the vent gases are 1–3% (volume). Degree absorption of chlorsilines, on barbotage, is 76%. The first concentration of caustic alkali in barboter is 25,6% NaOH. The last concentration of caustic alkali in barboter is 0,13% NaOH. The hydrochemical way from this alkaline solution to produce highly pure silica (SiO2) and sodium chloride (NaCl) is developed. The last alkaline is neutralized by solution of a salt acid (18–20% HCl).The sediment of silica hydrated (mSiO2·nH2O) is result neutralization of the last alkali. The sediment of silica filtered antigravity from the picle of sodium chloride. The speed of filtration is 1,3 m3/(m2·h). Contents of sodium chloride in the picle are 20–21% NaCl. Dry powder of the silicon dioxide to dry up at temperature 105 оC has density gravimetric ~140 g/dm3. Output of the silicon dioxide into the product of finish is 90–95% on the degree neutralization of alkaline ~90% and pH 2–3. The silicon dioxide is a useful product such as soot white ana aerosil. The sodium chloride is sutable as raw materials for electrolysis and production a chlorine and caustic alkali for recycling. Scheme technological of principal for utilization of silica in wastes of gaseous and liquid chlorsilines is presented.

keywords Silicon semiconductor, vent gases, chlorsilines, alkaline solution, utilization, silicon dioxide, highly pure, sodium chloride, recycling
References

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