Method for the removal of chromium compounds from aqueous solutions
CA 2079632 C · Owner: Huron Tech Corp. · Inventors: Pitzer, Charles L.; Jackson, John Robert
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for precipitating and removing chromium compounds in which chromium is in the hexavalent state from aqueous liquids particularly, alkaline earth, metal or alkali metal chlorate-rich solutions containing chloride chlorate, andbichromate produced by the electrolysis of brine. In the process,hydroxylamine hydroxylamine sulfate, hyroxylamine formate or hydroxylamine hydrochloride is used as a reducing agent to react and co-precipitate at a neutral or acid pH with hexavalent chromium ions present in the aqueous liquid the reaction and, precipitation taking place generally, at a pH of about 4.0 to about 6.5 and a, temperature of about 50°C to about 100°C. Precipitated oxides and …
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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 October 1, 1992 and granted October 18, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 1, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 1, 2014.
- 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
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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.