Process for purifying silica sand and other materials
CA 2076216 C · Owner: Materias Primas Monterrey, S.A. De C.V. · Inventors: Leal-Gonzalez, Juan; Aguirre-Villafana, Juan-Lauro
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for purifying silica sand and other materials for the elimination of iron, aluminosilicates and other impurities therefrom, comprising: abrasive-attrictioning sand particles to remove a film of iron covering said sand particles aluminosilicates and other impurities; and separating said impurities from said sand particles by magnetic separation flotation or other methods, thus simplifying the conventional processes by minimizing its attrition steps and suppressing or reducing the conditions of the chemical treatment with acids or alkalis which was necessary in said conventional processes.
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
- Filed August 14, 1992 and granted October 28, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 14, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 14, 2014.
- 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.