Removal of aox from bleach plant mill effluents by ph shift using the alkalinity/acidity sources available at the mill
CA 2089097 C · Owner: Fletcher Challenge Canada Limited · Inventors: Sullivan, Joseph; Hill, Derrick A.; Douek, Maurice
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for removal of adsorbable organic chlorine (AOX) in which the acid-soluble AOX present in kraft chlorination (CD) effluents (12) are destabilized and converted to inorganic chloride by pH shift using the alkalinity and acidity sources available at the mill; CD effluent, typically having a pH of 1-2 and E1 effluent (22) typically having a pH of 9-12 can be, mixed in various proportions to achieve a pH between 6.5-9.0 or the CD effluent is adjusted in pH to 6-11 with an alkaline composition (23) so that alkaline hydrolysis as well as precipitation of organic material occurs and the treated effluent (26) contains less AOX than present in the original untreated effluents; the AOX …
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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 September 18, 1991 and granted February 18, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 18, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 18, 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
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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.