Process for the fine purification of an aqueous alkali chloride solution for use in membrane electrolysis
CA 2044518 C · Owner: Dworak, Rainer · Inventors: Dworak, Rainer; Lohrberg, Karl
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The aqueous alkali chloride solution is coarsely purified first. In the succeeding fine purification means the solution, which contains calcium ions magnesium ions, and undissolved magnesium compounds is passed through a plu-, rality of purification stages (ion exchange stages) which, contain cation exchange granulate. In the fine purification means the solution having a pH value of about 10 to 11 is passed through a first ion exchange stage and the solution coming from the first ion exchange stage is acidified to decrease its pH value by at least 0.5. The solution is subsequently passed through at least one second ion exchange stage and a solution which is virtually free of undissolved …
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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 June 13, 1991 and granted March 26, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 13, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 13, 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.
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Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.