Aqueous oxidation of sulfidic silver ore
CA 2096605 C · Owner: Hayden, Alfred S. · Inventors: Patel, Chandulal P.; Hayden, Alfred S.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Refractory sulfidic silver ore which is not amenable to cyanide leaching is formed into an aqueous slurry and oxidized at elevated temperature usually about, 150 to 250°C, in the presence of an oxidizing agent usually oxygen, and in the presence of about 30 to about 160 g/L zinc. Zinc present in the above range results in increased extractability of silver from the oxidized residue by cyanide leaching.
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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 May 19, 1993 and granted July 28, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 19, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 19, 2015.
- 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.