FINE POWDER SILICON DIOXIDE PRODUCTION METHOD

1. Finely-divided silica which is, at the same time, suitable as a filtration auxiliary and as a beer stabilizer in the filtration of beer, characterised in that it is obtained by gradually adding waterglass and acid separately to an aqueous starting solution which contains dissolved sodium chloride...

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Bibliographische Detailangaben
1. Verfasser:	STEENKEN,GERHARD,DE
Format:	Patent
Sprache:	eng
Schlagworte:	AGEING BEER BIOCHEMISTRY CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOIDCHEMISTRY CHEMISTRY CLARIFICATION COMPOUNDS THEREOF ENZYMOLOGY INORGANIC CHEMISTRY METALLURGY MICROBIOLOGY MUTATION OR GENETIC ENGINEERING NON-METALLIC ELEMENTS PASTEURISATION PERFORMING OPERATIONS PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL PRESERVATION PURIFICATION SEPARATION SPIRITS STERILISATION THEIR RELEVANT APPARATUS TRANSPORTING VINEGAR WINE
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Beschreibung
Zusammenfassung:	1. Finely-divided silica which is, at the same time, suitable as a filtration auxiliary and as a beer stabilizer in the filtration of beer, characterised in that it is obtained by gradually adding waterglass and acid separately to an aqueous starting solution which contains dissolved sodium chloride in an amount of from 0.4 to 2% by weight, the volume of the starting solution being from at least 33%, by volume to at most 70% by volume, of the final volume on completion of precipitation, the metering operation being adjusted so that, during addition to the starting solution, the pH is from 3 to 10 and the temperature is from 50 to 95 degrees C, the silica suspension is adjusted to a pH of from 7 to 4 on completion of addition, the resulting silica is filtered, the resulting filter cake is washed with water and is immediately dried while avoiding substantial shearing forces and the mass is sieved after drying using a sieving apparatus, and silica particles are thereby obtained having a substantially spherical or rotationally ellipsoidal form, a minimum SiO2 content of 95% by weight, on a dry solids basis at about 100 degrees C, an Na2 O content of less than 0.25% by weight, a pH, measured on a 10% suspension in water, of from 4 to 7, a maximum Carman surface area of 100 m**2 /g, a standard test filtration time t0 , as defined in the following, of from 20 sec to 6 min and a ratio t120-1000 /t0 of from 0.7 to 6.5, wherein t120-1000 represents the test filtration time after stir stressing for 120 min at 1000 rpm, the stirring stress being determined by pouring 2 liters of water and 40 g of filtration auxiliary into a 2-litre measuring vessel which is 16 cm in height, has a bottom diameter of 12 cm and a top diameter of 14 cm, and lowering a stirring device having 4 blades 2 cm in length, which are inclined downwardly with respect to the horizontal at an angle of 25 degrees C, into the vessel to a depth of immersion of 8 cm and allowing it to rotate for 120 min at a constant speed of 1000 rpm.