摘要:
Preparation containing at least one photocatalytically active metal oxide powder with a specific surface area of at least 20 m2/g at least one wetting agent. Use of the preparation for weed control.
摘要:
Provided is a crystalline TiO2 powder in the form of aggregated primary particles having a variable sintering stability at a BET surface area of 70-100 m2/g and a rutile content of greater than 10% but less than or equal to 40%, and a process for preparing the crystalline TiO2 powder, which involves: introducing a TiCl4 vapor and, separately therefrom, H2 and a primary air into a mixing chamber to produce a gaseous mixture; igniting the gaseous mixture in a burner to produce a flame, which is burned into a reaction chamber to produce the crystalline TiO2 powder and gaseous substances; and separating the crystalline TiO2 powder from the gaseous substances, wherein the relative amounts of TiCl4 vapor, H2 and primary air are selected to provide crystalline TiO2 powder having the aforementioned BET surface area and rutile content, with the proviso that factor A has a value of 0.1-0.4·105 g/m2 in accordance within the following formula: factor A=105{[(TiCl4 vapor×H2)/(primary air×gaseous mixture)]/BET]}.
摘要:
Pyrogenically produced silicon dioxide powder with a specific surface area of between 5 and 600 m2/g and a carbon content of less than 500 ppm, which displays a specific dibutyl phthalate absorption of less than or equal to 1.2 g dibutyl phthalate/100 g SiO2 per m2 of specific surface area and a specific thickening action of less than 15 mPas/m2 of specific surface area. It is produced by supplying vaporous tetramethoxysilane and/or tetraethoxysilane together with air and separately hydrogen to a burner, and allowing the mixture of gases to react in a flame in a reaction chamber connected in series to the burner, and separating the solid reaction product from the gas stream by known means, the lambda value in the burner being between 0.95 and 1.5 and sufficient secondary air also being supplied to the reaction chamber that the lambda value in the reaction chamber is between 0.8 and 1.6. The invention also provides a dispersion containing the silicon dioxide powder and the use of the powder and of the dispersion.
摘要翻译:比热表面积为5〜600m 2 / g,碳含量小于500ppm的热解生成二氧化硅粉末,其特征在于邻苯二甲酸二丁酯的吸收小于或等于1.2 g二丁基邻苯二甲酸酯/ 100g SiO 2 / m 2比表面积和特定增稠作用小于15mPas / m 2比表面积。 它是通过将空气四甲氧基硅烷和/或四乙氧基硅烷与空气和单独的氢气一起向燃烧器供应的,并且允许气体混合物在与燃烧器串联连接的反应室中的火焰中反应,并将固体反应产物从 通过已知方式的气流,燃烧器中的λ值在0.95和1.5之间,并且足够的二次空气也被供应到反应室,反应室中的λ值在0.8和1.6之间。 本发明还提供了含有二氧化硅粉末的分散体以及粉末和分散体的用途。
摘要:
Silicon titanium mixed oxide powder having the following features: BET surface area of 5 to 300 m2/g, silica content, based on the total amount of the mixed oxide powder, of ≧0.1 to
摘要:
Stable, aqueous dispersion containing silicon dioxide powder having a hydroxyl group density of 2.5 to 4.7 OH/nm2, which is obtained from a silicon dioxide powder produced by a flame hydrolysis process under acid conditions. The dispersion is produced by incorporating the silicon dioxide powder into an aqueous solution by means of a dispersing device. The dispersion can be used to produce glass articles.
摘要:
Surface-modified, pyrogenically prepared silica is prepared by subjecting the pyrogenically prepared silica, which is in the form of aggregates of primary particles and possesses a BET surface area of 150±15 m2/g, the aggregates having an average area of 12 000-20 000 nm2, an average equivalent circle diameter (ECD) of 90-120 nm and an average circumference of 1150-1700 nm, to surface-modification in a known way. It can be used as a filler for thickening liquid systems.
摘要:
Aluminium oxide powder produced by flame hydrolysis and consisting of aggregates of primary particles, having a BET surface area of from 100 to 250 m2/g, a dibutyl phthalate absorption of from 50 to 450 g/100 g of aluminium oxide powder, which powder shows only crystalline primary particles in high-resolution TEM pictures. It is prepared by vaporizing aluminium chloride, transferring the vapour by means of a carrier gas to a mixing chamber and, separately therefrom, supplying hydrogen, air (primary air), which may optionally be enriched with oxygen and/or may optionally be pre-heated, to the mixing chamber, then igniting the mixture of aluminium chloride vapour, hydrogen, air in a burner and burning the flame into a reaction chamber that is separated from the surrounding air, subsequently separating the solid material from the gaseous substances and then treating the solid material with steam and optionally with air, the discharge rate of the reaction mixture from the mixing chamber into the reaction chamber being at least 10 m/s, and the lambda value being from 1 to 10 and the gamma value being from 1 to 15. It can be used as an ink-absorbing substance in ink-jet media.
摘要:
Dispersion containing pyrogenic silicon-titanium mixed oxide powders with a silicon dioxide content of 75 to 99.99 wt.-% and a titanium dioxide content of 0.01 to 25 wt. %, water and a basic, quaternary ammonium compound, wherein the mean aggregate diameter of the particles of the silicon-titanium mixed oxide powder in the dispersion is 200 nm at most. Process for the production of a titanium-containing zeolite with the use of the dispersion.
摘要:
Pyrogenically produced silicon dioxide powder in the form of aggregates of primary particles having a BET surface area of 90±15 m2/g, wherein the aggregates display an average surface area of 10000 to 20000 nm2, an average equivalent circle diameter (ECD) of 90 to 130 nm and an average circumference of 1000 to 1400 nm.It is produced by a pyrogenic process in which silicon tetrachloride and a second silicon component comprising H3SiCl, H2SiCl2, HSiCl3, CH3SiCl3, (CH3)2SiCl2, (CH3)3SiCl and/or (n-C3H7)SiCl3 are mixed with primary air and a combustion gas and burnt into a reaction chamber, secondary air also being introduced into the reaction chamber, and the feed materials being chosen such that an adiabatic flame temperature of 1810 to 1890° C. is obtained.Dispersion containing the pyrogenically produced silicon dioxide powder.
摘要:
Pyrogenically produced silicon dioxide powder with a specific surface area of between 5 and 600 m2/g and a carbon content of less than 500 ppm, which displays a specific dibutyl phthalate absorption of less than or equal to 1.2 g dibutyl phthalate/100 g SiO2 per m2 of specific surface area and a specific thickening action of less than 15 mPas/m2 of specific surface area. It is produced by supplying vaporous tetramethoxysilane and/or tetraethoxysilane together with air and separately hydrogen to a burner, and allowing the mixture of gases to react in a flame in a reaction chamber connected in series to the burner, and separating the solid reaction product from the gas stream by known means, the lambda value in the burner being between 0.95 and 1.5 and sufficient secondary air also being supplied to the reaction chamber that the lambda value in the reaction chamber is between 0.8 and 1.6. The invention also provides a dispersion containing the silicon dioxide powder and the use of the powder and of the dispersion.