Process for the manufacture of copper arsenate
CA 2002489 C · Owner: Cominco Ltd. · Inventors: Boateng, Daniel A. D.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
In a process for the manufacture of copper arsenate an, arsenic-containing material is subjected to an oxidative pressure leach with sodium hydroxide forming a leach solution containing sodium arsenate. Sodium arsenate solution is mixed with a solution of copper sulfate for the formation of a copper and arsenic-containing solution without the precipitation of copper arsenate. The copper and arsenic-containing solution is treated for the precipitation of copper arsenate with formation of sodium sulfate solution. At least one of the sodium arsenate-containing solution and the sodium sulfate solution is subjected to electrolysis with membranes for at least partial conversion to arsenic acid …
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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 November 8, 1989 and granted January 12, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 8, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 8, 2011.
- 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.