Electrolytic reduction of alumina
CA 2075892 C · Owner: Brooks Rand, Ltd. · Inventors: Brooks, Richard J.; Beck, Theodore R.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Finely divided particles of alumina are electrolytically reduced to aluminium in an electrolytic reduction vessel (11) having a plurality of vertically disposed, non-consumable anodes (16) and a plurality of vertically disposed dimensionally stable cathodes, (18) in closely spaced alternating arrangement with the anodes. A horizontally disposed gas bubble generator (35) is located, at the vessel bottom underlying the cathodes and the spaces between each pair of adjacent electrodes. The vessel contains a molten electrolyte bath (24) composed of (1) NaF+AlF3 eutectic (2) KF+AIF3 eutectic and (3) LiF. The alumina particles are maintained in suspension in the molten electrolyte bath by rising …
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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 January 28, 1991 and granted August 18, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 28, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 28, 2013.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.