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Expired Canadian patentCanada

Purification of bayer process liquors

CA 1236680 A · Owner: Nalco Chemical Company · Inventors: Roe, William J.; Malito, John T.

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Abstract From the Canadian patent

of the Invention, Bayer process liquors derived from the digestion of bauxites with a caustic solution are purified by removing at least a portion of the organic impurities present in the liquors. Removal of these impurities is accomplished by treating liquor containing dispersed therein solids generated by the Bayer process or added thereto such as red, mud particles, alumina trihydrate oxalate salt, or filter, aid with an organic polymeric water-soluble cationic, quaternary ammonium salt (POLYQUAT salt) which due to its cationic nature will adhere to the surface of the dispersed solids. The organic coating or layer adhered to the solids provides a receptive surface for the organic …

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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 May 17, 1988. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 17, 2005.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledNovember 22, 1985
GrantedMay 17, 1988
Term endedMay 17, 2005
Patent numberCA 1236680 A
Classification (IPC)C01F7/46

Timeline

Timeline From CIPO dates

1986198819901992199419961998200020022004Application filedNov 22, 1985Patent grantedMay 17, 1988Term endedMay 17, 2005

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