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Expired Canadian patentCanada

Aluminium electrowinning cells with non-carbon anodes

CA 2557955 C · Owner: Rio Tinto Alcan International Limited/Rio Tinto Alcan International Limitee · Inventors: Nguyen, Thinh T.; De Nora, Vittorio

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Abstract From the Canadian patent

A cell for electrowinning aluminium from alumina comprises: a metal-based , anode having an electrochemically active outer part comprising a layer that contains predominantly cobalt oxide CoO; and a fluoride-containing molten electrolyte in wich the active anode surface is immersed. The electrolyte is at a temperature below 950~C, in particular in the range from 910~ to 940~C. The electrolyte consists of: 6.5 to 11 weight.% dissolved alumina; 35 to 44 weight% aluminium fluoride; 38 to 46 weight% sodium fluoride; 2 to 15 weight% potassium fluoride; 0 to 5 weight% calcium fluoride; and 0 to 5 weight% in total of one or more further constituents.

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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 March 18, 2005 and granted October 9, 2012. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 18, 2025.
  • Certificates of supplementary protection extend only drug patents, and it isn't classified as one.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledMarch 18, 2005
GrantedOctober 9, 2012
Term endedMarch 18, 2025
Patent numberCA 2557955 C
Classification (IPC)C25C3/12

Timeline

Timeline From CIPO dates

2006200820102012201420162018202020222024Application filedMarch 18, 2005Patent grantedOct 9, 2012Term endedMarch 18, 2025

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