Production of phosphoric acid and hydrogen fluoride
CA 2107472 C · Owner: Phosphate Engineering & Construction Corp. · Inventors: Bouffard, Leif E.; Erickson, William R.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Fluosilicic acid is reacted with phosphate rock in order to produce wet process phoshoric acid and calcium fluoride which is later reacted with sulfuric acid to produce hydrogen fluoride and calcium sulfate. The hydrogen fluoride is then stripped from the phosphoric acid and recovered as either anhydrous hydrogen fluoride or concentrated hydrofluoric acid or reacted with aluminum trihydrate to produce aluminum fluoride; with sodium carbonate to produce sodium fluoride: bifluoride; or with ammonia to produce ammonium fluoride/bifluoride.
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 December 30, 1991 and granted July 30, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 30, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 30, 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.