Process of preparing mineral material with particular ceria-containing zirconium oxide grinding beads, obtained products and their uses
An object of the present invention is to provide a process to grind at least one mineral material in the presence of ceria (CeO 2 )-containing zirconium oxide grinding beads having a specific ceria content (of between 14 and 20% by weight relative to the total weight of said bead, preferably of between 15 and 18%, and most preferably of approximately 16%), and a specific average grain size (of less than 1 μm, preferably of less than 0.5 μm, and most preferably of less than 0.3 μm), wherein such beads are more resistant to wear than conventional beads of the prior art. Another object of the present invention lies in the ground material in the form of an aqueous suspension and in the form of a dry product. Another object of the present invention lies in the uses of such products in any sector making use of mineral materials, and notably in the paper, paint and plastic industries.
1. A ground mineral material obtained by a process of preparing a ground mineral material, wherein the process comprising the steps of:
(a) providing at least one mineral material, optionally in the form of an aqueous suspension, and
(b) grinding the mineral material in the presence of ceria-containing zirconium oxide
grinding beads to obtain a ground mineral material, wherein the ceria-containing
zirconium oxide grinding beads prior to grinding have:
a ceria content of between 15 and 18% by weight relative to total weight of the beads; and
an average grain size of less than 0.5 μm;
wherein the ground mineral material is an aqueous suspension or a dry product comprising natural calcium carbonate and/or precipitated calcium carbonate containing zirconium oxide and ceria in the range of 100 to 670 gram/ton of the ground mineral material, and wherein zirconium oxide and ceria weight ratio is in a range of 4 to 6.5.
2. The ground mineral material matter according to claim 1 , is in the form of an aqueous suspension.
3. The ground mineral material according to claim 1 , is in the form of a dry product.
4. The ground mineral material according to claim 1 , comprising a zirconium oxide and ceria weight ratio of 4.6 to 5.7.
5. The ground mineral material according to claim 1 , comprising a zirconium oxide and ceria weight ratio of 5.3.
6. The ground mineral material according to claim 1 , wherein the aqueous suspension contains less than 1000 ppm of zirconium oxide and less than 200 ppm ceria when the aqueous suspension is passed through a 40 micron sieve.
7. The ground mineral material according to claim 1 , which comprises natural calcium carbonate.
8. The ground mineral material according to claim 1 , which comprises precipitated calcium carbonate.
9. The ground mineral material according to claim 1 , having a steepness factor of at least about 30.
10. The ground mineral material according to claim 1 , having a steepness factor of at least about 40.
11. The ground mineral material according to claim 1 , having a steepness factor of at least about 45.
12. The ground mineral material according to claim 1 , having a d 50 from about 0.2 to 2.0 μm.
13. The ground mineral material according to claim 1 , having a d 50 from about 0.2 to 0.8 μm.
14. The ground mineral material according to claim 1 , having a d 50 from about 0.25 to 0.45 μm.
15. The ground mineral material according to claim 1 , wherein 80% of the ground mineral material particles are finer than 1 micron.
16. The ground mineral material according to claim 1 , wherein 85% of the ground mineral material particles are finer than 1 micron.
17. The ground mineral material according to claim 1 , wherein 90% of the ground mineral material particles are finer than 1 micron.
18. The ground mineral material according to claim 1 , wherein 95% of the ground mineral material particles are finer than 1 micron.
19. The ground mineral material according to claim 1 , having a BET specific surface area of less than 25 m 2 /g.
20. The ground mineral material according to claim 19 , wherein for a fraction of particles finer than 1 μm of greater than 95%, the BET specific surface area is less than 25 m 2 /g.
21. The ground mineral material according to claim 19 , wherein for a fraction of particles finer than 1 μm of greater than 90%, the BET specific surface area is less than 20 m 2 /g.
22. The ground mineral material according to claim 19 , wherein for a fraction of particles finer than 1 μm of greater than 85%, the BET specific surface area is less than 18 m 2 /g.
23. The ground mineral material according to claim 19 , wherein for a fraction of particles finer than 1 μm of greater than 80%, the BET specific surface area is less than 15 m 2 /g.
24. The ground mineral material according to claim 1 , wherein the aqueous suspension contains at least one dispersing and/or grinding aid agent present in a weight % relative to the total dry mineral material ranging from 0 to 2%.
25. The ground mineral material according to claim 1 , wherein the aqueous suspension contains at least one dispersing and/or grinding aid agent present in a weight % relative to the total dry mineral material ranging from 0.2 to 1.4%.
26. The ground mineral material according to claim 1 , wherein the aqueous suspension contains at least one dispersing and/or grinding aid agent present in a weight % relative to the total dry mineral material ranging from 0.5 to 1.2%.
27. Paper, paint or plastic comprising the ground mineral material according to claim 1 .