Production of mixed fertilizers from crude phosphates
CA 1080499 A · Owner: Kemira Oy · Inventors: Suppanen, Pekka I. J.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Crude phosphate is leached with nitric acid to produce an acid slurry, which is thereafter neutralized with ammonia in two successive stages while simultaneously cooling it and adding acid part of the crude phosphate phosphorus being replaced with phosphoric acid added to the slurry to be neutralized and in such, a manner that at maximum 40 % of the phosphoric acid is fed to the first neutralization stage and the rest is fed to the second neutralization stage, whereby the acidity of the slurry is adjusted to pH 2.5 - 4.5 during the first and to pH 5.0 - 6.0 during the second neutralization stage.
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
- Granted July 1, 1980. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended July 1, 1997.
- 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.