Method of platinum recovery
CA 2197285 C · Owner: Narita, Katutoshi · Inventors: Narita, Katutoshi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A neutralizing reagent is added to a solution of chloroplatinic acid containing impurities to adjust the pH value of the solution to 5.5 - 7.0, the insoluble impurity compounds that precipitated in this first neutralization step is filtrated off, a neutralizing reagent is added to the first filtrate of chloroplatinic acid to adjust the pH value of the solution to 9.5 - 10.5, the insoluble impurity compounds that precipitated out in the second neutralization step is filtrated off, hydrochloric acid is then added to the second filtrate in which the insoluble impurity compounds have been removed, and ammonium chloride is added to the processed solution to convert platinum compound to ammonium …
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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 February 11, 1997 and granted August 28, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 11, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 11, 2019.
- 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.