SiO2 slurry for the production of quartz glass as well as the application of the slurry

US8158542B2 · kind B2 · utility

Assignee

• HERAEUS QUARZGLAS GMBH & CO. KG · DE

Inventors

• Waltraud Werdecker · Hanau, DE
• Norbert Traeger · Maintal, DE
• Juergen Weber · Erlangen, DE

Key dates

• Filing date: Sep 12, 2007
• Grant date: Apr 17, 2012
• Expiry date: Jul 3, 2028

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C03C2218/11
• WIPO field: Other special machines
• WIPO sector: Mechanical engineering

Abstract

A known SiO2 slurry for the production of quartz glass contains a dispersion liquid and amorphous SiO2 particles with particle sizes to a maximum of 500 μm, wherein the largest volume fraction is composed of SiO2 particles with particle sizes in the range 1 μm-60 μm, as well as SiO2 nanoparticles with particle sizes less than 100 nm in the range 0.2-15% volume by weight (of the entire solids content). In order to prepare such a slurry for use, and to optimize the flow behavior of such a slurry with regard to later processing by dressing or pouring the slurry mass, and with regard to later drying and sintering without cracks, the invention suggests a slurry with SiO2 particles with a multimodal distribution of particle sizes, with a first maximum of the sizes distribution in the range 1 μm-3 μm and a second maximum in the range 5 μm-50 μm, and a solids content (percentage by weight of the SiO2 particles and the SiO2 nanoparticles together) in the range 83%-90%.