Chemistry of inorganic compounds – Silicon or compound thereof – Oxygen containing
Reexamination Certificate
2005-02-01
2005-02-01
Silverman, Stanley S. (Department: 1754)
Chemistry of inorganic compounds
Silicon or compound thereof
Oxygen containing
C423S335000, C065S017300, C065S021100, C501S054000
Reexamination Certificate
active
06849242
ABSTRACT:
The granule consists of individual granules approximately spherical in shape, having a pore volume of 0.5 cm3, a mean diameter of pores of 50 nm or less, a specific surface area of 100 m2/g or less, and a bulk density of 0.7 g/cm3or higher. It is produced by dispersing a fumed silica obtained by hydrolysis of a silicon compound into pure water to obtain a slurry, and drying the slurry. The granule is used for producing high purity synthetic quartz glass powder. The method further comprises: a first heat treatment under an oxygen-containing atmosphere, a second heat treatment in a temperature range of from 600 to 1100° C., and a third heat treatment in a temperature range of from 1100 to 1300° C. under an atmosphere containing hydrogen chloride; and a step of densification comprising calcining the product at a temperature not higher than 1500° C. under vacuum or in an atmosphere of gaseous hydrogen or gaseous helium. To calcine the powder without causing fusion adhesion of the particles, bubbling fluidization of said porous silica granule is conducted by supplying gaseous helium and calcining thereof in a temperature range of from 1000 to 1600° C.
REFERENCES:
patent: 3383172 (1968-05-01), Biegler et al.
patent: 4042361 (1977-08-01), Bihuniak et al.
patent: 4126422 (1978-11-01), Brandes
patent: 4528163 (1985-07-01), Albrecht
patent: 5030433 (1991-07-01), Mehrotra
patent: 5145510 (1992-09-01), Saito et al.
patent: 5516350 (1996-05-01), Onoda et al.
patent: 5643347 (1997-07-01), Werdecker et al.
patent: 5683483 (1997-11-01), Yosiaki et al.
patent: 5979186 (1999-11-01), Koppler et al.
patent: 6129899 (2000-10-01), Katsuro et al.
patent: A-Hei 717706 (1995-01-01), None
patent: 09165214 (1995-12-01), None
patent: 10101324 (1998-04-01), None
patent: A-Hei 11130417 (1999-05-01), None
Arnold Klaus
Hoshikawa Kasumi
Koeppler Rainer
Kreis Fritz-Ulrich
Matsui Hiroshi
Cooke Colleen P.
Heraeus Quarzglas GmbH & Co. KG
Milde & Hoffberg LLP
Shin-Etsu Quartz Products Co. Ltd.
Silverman Stanley S.
LandOfFree
Porous silica granule, method for producing the same, and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Porous silica granule, method for producing the same, and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Porous silica granule, method for producing the same, and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3509267