Process for obtaining high purity silica
CA 1184740 A · Owner: Indusmin Limited · Inventors: Gerritse, Martin L.G.; Puetz, Gilbert H.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method of producing high purity silica containing less than 2 ppm iron oxides and less than 50 ppm alumina from particulate silica or quartz concentrates containing both surface and occluded mineral impurities wherein the concentrate is agitated with an aqueous solution containing 3-20% by weight hydrofluoric acid at a temperature between 50°C and the boiling point of the solution. The impurities dissolve at a greater rate than the silica and can be washed away or separated as a slime.
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 April 2, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended April 2, 2002.
- 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.