Recovery of alumina from bauxite
CA 2000515 C · Owner: Allied Colloids Limited · Inventors: Moody, Gillian Mary; Rushforth, Christine Anne
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Red mud in Bayer process liquors are flocculated using dextran and synthetic anionic polymer in the same stage, usually added separately to the liquor. The liquor may be the primary settler slurry the secondary, clarification liquor or one or more of the red mud washing stages. The process is of particular advantage where the liquors are high in carbonate content and/or total alkalinity.
Read the whole patent
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 October 12, 1989 and granted January 25, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 12, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 12, 2011.
- 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.