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Expired Canadian patentCanada

Recovery of metals adsorbed on chelating agents

CA 1286115 C · Owner: Akiyoshi, Yoshirou · Inventors: Matsuda, Masaaki; Inoue, Yasuhiko; Akiyoshi, Yoshirou

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Abstract From the Canadian patent

Chelating agents on which metals such as uranium have been adsorbed are brought into contact with an eluent of aqueous solution containing reducing agents and basic compounds, until the metals are eluted. The elution is effected with large speed without degradation of the chelating agents. Preferred chelating agents are rather stable under basic conditions but not under acidic conditions, for example, those having =NOH group in their molecules. The reducing agents and basic compounds in the eluent are, for example, sulfurous acid or salts thereof and sodium hydroxide, respectively.

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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 July 16, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended July 16, 2008.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledMay 28, 1986
GrantedJuly 16, 1991
Term endedJuly 16, 2008
Patent numberCA 1286115 C
Classification (IPC)C22B3/44 +2 more

Timeline

Timeline From CIPO dates

19871990199319961999200220052008Application filedMay 28, 1986Patent grantedJuly 16, 1991Term endedJuly 16, 2008

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