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Expired Canadian patentCanada

Process for leaching sulfide minerals

CA 1062472 A · Owner: E.I. Du Pont De Nemours And Company · Inventors: Watts, John C.

CIPO record

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Drawings and full text

Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

An improvement in the process of leaching metal sulfide minerals with an oxidative leaching solution is obtained by adding to the leaching solution over only a portion of the leaching cycle aqueous hydrogen peroxide in an amount ranging from about 2 to about 25 percent by weight of the quantity of hydrogen peroxide required to bring the metal value of the mineral into solution if hydrogen peroxide were used as the sole oxidizing agent.

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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

  • Granted September 18, 1979. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 18, 1996.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Filed—
GrantedSeptember 18, 1979
Term endedSeptember 18, 1996
Patent numberCA 1062472 A
Classification (IPC)C22B3/06 +1 more

Timeline

Timeline From CIPO dates

198019821984198619881990199219941996Patent grantedSep 18, 1979Term endedSep 18, 1996

Sources & verification

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