Phosphonic acids and their uses in separation
CA 2001976 C · Owner: Gatrone, Ralph C. · Inventors: Horwitz, Earl P.; Nash, Kenneth L.; Gatrone, Ralph C.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Diphosphonic acids and their derivatives such as vinylidene-1,1-diphosphonic acid and, 1,2-dihydroxyethane-1,1-diphosphonic acid complex metal ions especially in II-VI oxidation states, to form eater soluble complexes especially in strong acid media. After complexing the, metal complex is separated and then the metal is recovered by decomposition under mild conditions preferably of heat and/or oxidation to release the metal for disposal or recovery and form especially environmentally innocuous byproducts.
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 November 1, 1989 and granted April 18, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 1, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 1, 2011.
- 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.