Process for producing sodium hydroxide and ammonium sulphate from sodium sulphate
CA 2048815 C · Owner: Thompson, Jack S. · Inventors: Thompson, Jack S.; Genders, David
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for producing sodium hydroxide and ammonium sulfate by electrolysing an aqueous solution of sodium sulfate is disclosed. The process is carried out in a three-compartment electrolytic cell having a central compartment separated from an anode and a cathode compartment by, respectively anion selective, and cation selective ion exchange membrane. The solution of sodium sulfate is circulated through the central compartment while solutions of sodium hydroxide and ammonium sulfate are circulated, respectively, through the cathode and the anode compartment. During the process, ammonia is added to the anolyte to at least partially neutralize sulfuric acid produced in the anode compartment …
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 August 8, 1991 and granted December 23, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 8, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 8, 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
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.