Method for recovery of copper from copper-containing materials
CA 2043473 A1 · Owner: Kruesi, William H. · Inventors: Kruesi, William H.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
METHOD FOR RECOVERY OF COPPER FROM, COPPER-CONTAINING MATERIALS" Abstract, A process for precipitating solid hydrates of cupric tetrammine sulfate from a solution, wherein the solution contains at least 40 grams per liter of free ammonia at, least 50 grams per liter of ammonium sulfate and wherein the temperature of the solution is less than 21°C. The hydrates of cupric tetrammine sulfate can be converted to additional useful copper compounds.
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 May 29, 1991. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended May 29, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 29, 2013.
- 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.