Method for purifying industrial sewage water
CA 2120989 C · Owner: Allgulin, Torkel · Inventors: Allgulin, Torkel
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention relates to a method for purifying contaminated industrial sewage water solutions or other aqueous solutions having a similar contaminant profile, normally containing ions of several metals and other elements such as As, Bi, Sb, P and Se by, precipitation in two stages and by returning the precipitate separated from the second precipitation stage to the first precipitation stage. Precipitation is effected in a first stage by adding lime in a surplus quantity, wherewith the major part of the contaminant content is precipitated. The formed precipitated is isolated and removed together with residual lime. Precipitation of remaining contaminant content is effected by adding …
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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 April 11, 1994 and granted July 14, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 11, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 11, 2016.
- 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.