Traitement en cours

Veuillez attendre...

Paramétrages

Paramétrages

Aller à Demande

1. WO1999002455 - PROCEDE DE PRODUCTION D'UN PRODUIT AU PHOSPHATE MONOCALCIQUE

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

[ EN ]

CLAIMS

1. A method for the production of a mono-calcium phosphate product, the method including the steps of
dispersing unslaked lime in an aqueous solution of
phosphoric acid in a mixing zone to form a generally homogeneous reaction mixture and allowing reaction between the unslaked lime and the acid in the reaction mixture to proceed until the reaction mixture reaches a predetermined temperature;
transferring the reaction mixture to a reaction zone when it has reached the predetermined temperature;
allowing the reaction to proceed essentially to completion in the reaction zone to form the mono-calcium phosphate product; and
isolating the mono-calcium phosphate product formed.

2. A method as claimed in Claim 1, in which the aqueous phosphoric acid solution has a concentration of 45 - 48% (P2O5 equivalent).

3. A method as claimed in Claim 1 or Claim 2, in which the phosphoric acid is ortho-phosphoric acid.

4. A method as claimed in any one of the preceding claims, which includes the prior step of admixing concentrated phosphoric acid solution.

5. A method as claimed in Claim 1, characterized in that the unslaked lime contains 85 - 95 % available CaO.

6. A method as claimed in Claim 1 or Claim 5, characterized in that the size distribution of the unslaked lime is such that about 10 % is retained on a 2,35 mm sieve.

7. A method as claimed in Claim 1 or Claim 2, characterized in that the amount of unslaked lime and the amount of aqueous phosphoric acid used in the dispersing step are selected to produce a mono-calcium phosphate product having a total phosphorus content of not less than 21 % (m/m), a total calcium content of not more than 25 % (m/m) and a moisture content of 1

8. A method as claimed in Claim 1 or Claim 2, characterized in that the amount of unslaked lime and the amount of aqueous phosphoric acid used in the dispersing step are selected to produce a reaction mixture containing 33 - 38 % lime and 46 - 50 % P2O5 equivalent.

9. A method as claimed in Claim 1 or Claim 2, characterized in that the predetermined temperature is 85 - 95° C.

10. A method as claimed in Claim 1 or Claim 2, characterized in that the dispersing step is conducted over a period of 4 - 10 seconds.

11. A method as claimed in Claim 4, characterized in that the prior step of admixing concentrated phosphoric acid with water in the mixing zone is conducted over a period of 4 - 8 seconds.

12. A method as claimed in Claim 1 or Claim 2, characterized in that the transferring step is conducted over a period of 5 - 8 seconds.

13. A method as claimed in Claim 1 or Claim 2, characterized in that the volume of the mixing zone is 8 - 16 times larger than the volume of the reaction mixture.

14. A method as claimed in Claim 1 or Claim 2, characterized in that it includes cooling the mixing zone.

15. An installation for the production of a mono-calcium phosphate product, characterized in that the installation includes
a mixing zone and a separate reaction zone,
dispensing means arranged to dispense a predetermined quantity of phosphoric acid and a predetermined quantity of unslaked lime into the mixing zone to produce a mixture;

dispersing means for rapidly dispersing the unslaked lime in the phosphoric acid in the mixing zone to form a generally homogeneous reaction mixture; and
transferring means for rapidly transferring the reaction mixture from the mixing zone to the reaction zone when the reaction mixture has reached a predetermined temperature.

16. An installation as claimed in Claim 15, characterized in that the dispensing means is arranged to dispense, in addition, a predetermined quantity of water into the mixing zone.

17. An installation as claimed in Claim 15 or Claim 16, characterized in that the mixing zone is provided with cooling means.

18. An installation as claimed in Claim 16, characterized in that the dispensing means is provided with load cells for measuring, in use, the mass of the unslaked lime, the phosphoric acid and the water in the dispensing means.

19. An installation as claimed in Claim 15 or Claim 16, characterized in that the reaction zone is in the form of two or more static dens.

20. An installation as claimed in Claim 15 or Claim 16, characterized in that the mixing zone comprises a mixing vessel of steel having a wall thickness of 1,5 - 2,5 mm.

21. An installation for the production of a mono-calcium phosphate product, substantially as herein described with reference to the accompanying drawings.

22. A method as claimed in claim 1 carried out on an installation as claimed in any one of claims 15 to 21.

23. A method as claimed in claim 1 substantially as herein described and illustrated.

24. Mono-calcium phosphate produced by the method claimed in any one of claims 1 to 14, 22 and 23.