Phosphate acidulation utilizing hf acid
CA 2411977 A1 · Owner: Breed, Claude E. · Inventors: Mcgill, Kenneth E.; Sweat, Samuel Franklin; Breed, Claude E.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Phosphoric acid, essentially free from impurities is prepared by reacting , aqueous hydrofluoric acid with phosphate in particles of calcium bearing phosphate rock to form a calcium fluoride pseudomorph solid from which filtergrade phosphoric acid is separated. By reacting the pseudomorph solid with sulfuric acid and thermally treating the reaction product the HF can be , liberated and recycled back to the reaction step of the process. All of the impurities from the phosphate rock are contained in the resulting CaSO4.
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 June 7, 2001. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended June 7, 2021.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 7, 2023.
- 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.