Process of preparing low-iron ammonium alum
CA 2129926 A1 · Owner: Metallgesellschaft Aktiengesellschaft · Inventors: Roller, Gunter; Stein, Dieter; Litzenberger, Ingo F.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process is disclosed for preparing low-iron ammonium alum from an aqueous ammonium alum solution which contains Fe3+ ions. This aqueous ammonium alum solution which has a pH not in excess of 5, is passed through at least one electrolytic cell to reduce at least one half of the Fe3+ ions in the solution to Fe2+ ions. The solution is cooled and ammonium alum is crystallized whereas the Fe2+ ions remain in the liquid phase.
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 11, 1994. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended August 11, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 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.