A process for the separation of sulphides from pulping liquors using amphoteric resins
CA 2277833 C · Owner: Eco-Tec Limited · Inventors: Thompson, Rokhsareh; Sheedy, Michael; Paleologou, Michael
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process using an amphoteric ion-exchange resin also known as a "snake-cage , polyelectrolyte" resin contained in an ion retardation unit (9) separates kraft white liquor (8) into sulphide-rich (12) and caustic-rich (10) components. The sulphide-rich component (12) can be used in the initial stage of pulping (1), pretreatment of wood chips prior to pulping or it can be used , to make polysulphide-rich liquor. The caustic-rich component (10) can be used in the final delignification phase, in place of sodium hydroxide or white liquor in oxygen delignification, pH adjustment and flue gas scrubbing. The same system can be used to separate green (6) and polysulphide liquors (8a) into …
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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 23, 1998 and granted August 19, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 23, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 23, 2020.
- 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
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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.