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| Pietriková A., Búgel M., Buršák M. |
| PREPARATION TECHNIQUE OF SILICAGEL FROM SERPENTINE |
Abstract
Well-known methods for silicagel producing don’t exploit the possibility of acquirement by the chemical treatment of silica dioxide SiO2 produced from serpentine mineral resource. The problem of silicagel production, which properties comply with both the requirements for quartz glass production and the use in column chromatography, is analysed in this article. Demanding requirements on silicagel was putted for these aims as high purity, fineness of powder particles, and smooth wall of oval silicagel particles. Silicone dioxide SiO2 gained from the serpentine raw material treatment was used as input material. Secondary serpentine deposited in Dobsina heap is residue from the both mining and treatment of chrysolite asbestos in the past and it is the disturbing element from the point of view of land and environment. Paper shows on the other possibility of use of one from the product of chemical reaction arisen from serpentine treatment.
Suggested preparation technique supposes that input reactant silica dioxide SiO2 has before transfer to sodium silicate Na2SiO3 purity minimally 98. 9 %.
The reason for prevention of immediate polycondensation from the sodium silicate brine Na2SiO3 is filtering still hot Na2SiO3 brine without entry carbon dioxide from air. Changing mol ratio of reactants has determinant influence on Na2SiO3 brine extraction course. Following up oxidation and acidification without the previous “gelatining” support ideal course of polycondensation Si-O-Si chains to silicagel. Ideal course of silicagel purification in nitric acid essential in requirement of high purity is under way after previous powderize of silicagel on fine powder.
Physical properties of silicagel are during the whole manufacturing process controlled by cooling and thawing, washing and controlled drying under lower pressure at the temperature 105°C.
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| Keywords: silikagél|serpentinit|oxid kremičitý|kremičité sklá| |
| No 2 (2005), p. 152-160 |
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