Method of making high purity dense silica of large particle size
CA 1318481 C · Owner: Su, Sophia R. · Inventors: Su, Sophia R.; Fitzpatrick, Leo F.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Abstract, A method of making high purity dense silica of large, particle size is described. Tetraethylorthosilicate is mixed with ethanol and is added to a dilute acid solution having a pH of about 2.25. The resulting solution is digested for about 5 hours, then 2N ammonium hydroxide is added to form a gel at a pH of 8.5. The gel is screened through an 18-20 mesh screen, vacuum baked calcined in an, oxygen atmosphere and finally heated to about 1200°C in air to form a large particle size, high purity dense, silica.
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted June 1, 1993. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 1, 2010.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.