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Expired Canadian patentCanada

Methods and compositions for reducing precipitation from acid solutions

CA 2108702 C · Owner: Gdanski, Rick D. · Inventors: Gdanski, Rick D.; Brezinski, Michael M.

CIPO record

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Abstract From the Canadian patent

Methods and compositions for reducing the precipitation of metal sulfides from acid solutions are provided. The methods basically comprise reducing the precipitation of metal sulfide compounds from an aqueous acid solution when the solution dissolves sulfide and metal ions by combining at least one oxime with the acid solution in an amount whereby the oxime preferentially reacts with sulfide ions in the solution and thereby prevents the sulfide ions from reacting with metal ions therein.

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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 October 19, 1993 and granted April 29, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 19, 2013.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 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.
FiledOctober 19, 1993
GrantedApril 29, 1997
Term endedOctober 19, 2013
Patent numberCA 2108702 C
Classification (IPC)E21B43/27 +1 more

Timeline

Timeline From CIPO dates

1994199619982000200220042006200820102012Application filedOct 19, 1993Patent grantedApril 29, 1997Term endedOct 19, 2013

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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.