Silver recovery from spent photographic solutions
CA 2000527 A1 · Owner: Kunda, Wasyl · Inventors: Etsell, Thomas H.; Kunda, Wasyl
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process is disclosed for recovering silver sulfide from a silver containing spent photographic fixer solution The process is particularly suited for treating the fixer solution in a manner which enables recycling of the solution and hence considerable reduction in cost in the fixer solution and reducing pollution to the environment. The process comprises introducing hydrosulfide into the silver containing spent fixer solution to precipitate silver sulfide. The precipitate is isolated from the fixer solution to remove thereby silver and hence enable recycle of the fixer solution.
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 October 12, 1989. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended October 12, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 12, 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.