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 (CeO2)-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. An other 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. An other 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 process of preparing a ground mineral material, 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.
2. The process according to claim 1 , wherein the ceria-containing zirconium oxide grinding beads have a ceria content of about 16% by weight relative to total weight of the beads.
3. The process according to claim 1 , wherein the ceria-containing zirconium oxide grinding beads have an average grain size of less than 0.3 μm.
4. The process according to claim 1 , wherein the beads have a diameter of between 0.2 and 1.5 mm prior to grinding.
5. The process according to claim 1 , wherein the beads have a diameter of between 0.4 and 1.0 mm prior to grinding.
6. The process according to claim 1 , wherein step (b) occurs at a pH of above 7.
7. The process according to claim 1 , wherein step (b) occurs at a pH of above 10.
8. The process according to claim 1 , wherein step (b) occurs at a pH of above 11.
9. The process according to claim 1 , wherein step (b) occurs at a temperature of above 60° C.
10. The process according to claim 1 , wherein step (b) occurs at a temperature of above 90° C.
11. The process according to claim 1 , wherein step (b) occurs at a temperature of above 100° C.
12. The process according to claim 1 , wherein in step (b), the mineral material is ground in the form of an aqueous suspension at a solids content of from 10 to 80% by dry weight of mineral material.
13. The process according to claim 1 , wherein in step (b), the mineral material is ground in the form of an aqueous suspension at a solids content of from 50 to 80% by dry weight of mineral material.
14. The process according to claim 1 , wherein in step (b), the mineral material is ground in the form of an aqueous suspension at a solids content of from 60 to 78% by dry weight of mineral material.
15. The process according to claim 1 , wherein 0.2 to 2 weight % of at least one dispersing or grinding aid agent, relative to total dry mineral material, is added before, during or after step (b).
16. The process according to claim 1 , wherein 0.2 to 1.4 weight % of at least one dispersing or grinding aid agent, relative to total dry mineral material, is added before, during or after step (b).
17. The process according to claim 1 , wherein 0.5 to 1.2 weight % of at least one dispersing or grinding aid agent, relative to total dry mineral material, is added before, during or after step (b).
18. The process according to claim 1 , wherein the mineral material is natural calcium carbonate, precipitated calcium carbonate, clay, talc, Al 2 O 3 , TiO 2 or any mixture thereof.
19. The process according to claim 1 , wherein the mineral material is natural calcium carbonate, precipitated calcium carbonate, clay, talc or any mixture thereof.
20. The process according to claim 1 , wherein the mineral material is a mixture of natural calcium carbonate, precipitated calcium carbonate and clay.
21. The process according to claim 1 , wherein the mineral material is a mixture of natural calcium carbonate, precipitated calcium carbonate and talc.
22. The process according to claim 1 , wherein the mineral material is a mixture of natural calcium carbonate and precipitated calcium carbonate (PCC).
23. The process according to claim 22 , wherein the PCC is present at a weight fraction of 10 to 90% relative to total weight of the mineral material.
24. The process according to claim 22 , wherein the PCC is present at a weight fraction of 20 to 80% relative to total weight of the mineral material.
25. The process according to claim 22 , wherein the PCC is present at a weight fraction of 30 to 70% relative to total weight of the mineral material.
26. The process according to claim 1 , wherein the mineral material provided in step (a) is in a form of an aqueous suspension containing from 10 to 80% by dry weight of mineral material.
27. The process according to claim 1 , wherein the mineral material provided in step (a) is in a form of an aqueous suspension containing from 50 to 80% by dry weight of mineral material.
28. The process according to claim 1 , wherein the mineral material provided in step (a) is in a form of an aqueous suspension containing from 60 to 78% by dry weight of mineral material.
29. The process according to claim 1 , wherein the mineral material provided in step (a) is in a form of an aqueous suspension of natural calcium carbonate.
30. The process according to claim 1 , further comprising subjecting the ground mineral material obtained in step (b) to one or more of a screening, an upconcentrating, and a drying step.