Method for producing synthetic quartz glass granules
US9409810B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 20, 2013 |
| Grant date | Aug 9, 2016 |
| Priority date | — |
| Expiry date | Mar 20, 2033 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03B2201/03
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
The production of quartz glass granules comprises the granulation of pyrogenically produced silicic acid and the formation of a SiO2 granulate (9), the drying and cleaning of the SiO2 granulate (9) by heating in an atmosphere containing halogen, and the vitrification of the SiO2 granulate (9) under a treatment gas which contains at least 30% by volume of helium and/or hydrogen. This process is time-consuming and expensive. In order to provide a method which, starting from a porous SiO2 granulate (9), allows the cost-effective production of dense, synthetic quartz glass granules suitable for melting bubble-free components of quartz glass, the invention proposes that the cleaning and vitrification of the SiO2 granulate (9) and a post-treatment of the vitrified quartz glass granules are carried out in each case in a rotary tube (6) of a rotary kiln (1), said rotary tube rotating about a central axis (7), wherein the rotary tube (6) comprises an inner wall made of a ceramic material during vitrification, and wherein the vitrified quartz glass granules are subjected to a post-treatment during a treatment period of at least 10 minutes in an atmosphere which contains less than 20% of heli…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.