Method of producing oxidized white liquor from black liquor
CA 2224765 C · Owner: Sethna, Rustam H. · Inventors: Kirschner, Mark J.; Sethna, Rustam H.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
White liquor produced from black liquor is partially or completed oxidized. The white liquor contains dregs that are utilized as a carbon based catalyst. Dregs are produced by separating the dregs from green liquor an intermediate product between the black liquor and the oxidized white liquor. After formation of the oxidized white liquor, the dregs are separated therefrom to form a waste dreg stream which can be recycled so that part of the dregs present within the dregs containing white liquor stream to be oxidized is contributed by the waste dreg stream.
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 December 15, 1997 and granted May 21, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 15, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 15, 2019.
- 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.