Process to disperse and/or grind and/or concentrate calcium carbonate in aqueous media using an aqueous solution containing zirconium compounds

1. A process for manufacturing a calcium carbonate product comprising the steps of (i) contacting calcium carbonate with a grinding aid agent in water to obtain a calcium carbonate-containing slurry, wherein the grinding aid agent comprises a zirconium compound selected from the group consisting of ammonium zirconium carbonate, potassium zirconium carbonate, and mixtures thereof, and (ii) grinding the calcium carbonate-containing slurry to obtain a calcium carbonate product.

2. The process according to claim 1 , wherein the grinding aid agent is ammonium zirconium carbonate.

3. The process according to claim 1 , wherein the grinding aid agent is potassium zirconium carbonate.

4. The process according to claim 1 , wherein the grinding aid agent is supplied in a form of an aqueous solution and/or an aqueous suspension or an aqueous emulsion, containing from 0.01% to 10% by dry weight of the zirconium compound.

5. The process according to claim 1 , wherein the grinding aid agent is supplied in a form of an aqueous solution or an aqueous suspension or an aqueous emulsion, containing from 0.03% to 5% by dry weight of the zirconium compound.

6. The process according to claim 1 , wherein the grinding aid agent is supplied in a dry form.

7. The process according to claim 1 , wherein in step (i), calcium carbonate in a dry form or in a form of an aqueous dispersion or an aqueous suspension or an aqueous filtercake, is added to an aqueous suspension or an aqueous emulsion or an aqueous solution containing the grinding aid agent to obtain the calcium carbonate-containing slurry.

8. The process according to claim 1 , wherein in step (i), the zirconium compound in a dry form or in a form of an aqueous suspension or an aqueous emulsion or an aqueous solution, is added to an aqueous dispersion or an aqueous suspension or an aqueous filtercake of calcium carbonate in water to obtain the calcium carbonate-containing slurry.

9. The process according to claim 1 , wherein in step (i), calcium carbonate in a form of a pigment cake is added to an aqueous suspension or an aqueous emulsion containing the zirconium compound to obtain the calcium carbonate-containing slurry.

10. The process according to claim 9 , wherein the pigment cake is a filter-cake or a centrifuge cake or a cake obtained by a process of electro-concentration.

11. The process according to claim 9 , wherein the cake has a moisture content above 20% by dry weight of mineral matter.

12. The process according to claim 1 , wherein in step (i), the zirconium compound in a dry form or in a form of an aqueous suspension or an aqueous emulsion, is mixed with a pigment cake in water to obtain the calcium carbonate-containing slurry.

13. The process according to claim 12 , wherein the pigment cake is a filter-cake or a centrifuge cake or a cake obtained by a process of electro-concentration.

14. The process according to claim 12 , wherein the cake has a moisture content above 20% by dry weight of mineral matter.

15. The process according to claim 1 , wherein the calcium carbonate slurry comprises one or more phosphate-free additives.

16. The process according to claim 1 , wherein the calcium carbonate slurry comprises one or more polyacrylates.

17. The process according to claim 1 , wherein the calcium carbonate slurry does not include any grinding aid agent other than the zirconium compound.

18. The process according to claim 1 , wherein the calcium carbonate product obtained in step (ii) is concentrated.

19. The process according to claim 1 , wherein in step (ii), the calcium carbonate-containing slurry is ground at a concentration of dry matter of less than 40% by weight, and the calcium carbonate product so obtained is concentrated.

20. The process according to claim 1 , wherein the calcium carbonate product obtained in step (ii) is dried.

21. The process according to claim 1 , wherein the calcium carbonate product contains more than 45% in dry weight of calcium carbonate.

22. The process according to claim 1 , wherein the calcium carbonate product contains more than 65% in dry weight of calcium carbonate.

23. The process according to claim 1 , wherein the calcium carbonate product contains more than 78% in dry weight of calcium carbonate.

24. The process according to claim 1 , wherein the calcium carbonate product consists essentially of (i) calcium carbonate, (ii) ammonium zirconium carbonate, potassium zirconium carbonate, or mixtures thereof, and (iii) water.

25. The process according to claim 1 , wherein the calcium carbonate product consists essentially of (i) calcium carbonate, (ii) ammonium zirconium carbonate, potassium zirconium carbonate, or mixtures thereof, (iii) water, and (iv) one or more phosphate-free additives.

26. The process according to claim 1 , wherein the calcium carbonate product consists essentially of (i) calcium carbonate, (ii) ammonium zirconium carbonate, potassium zirconium carbonate, or mixtures thereof, (iii) water, and (iv) one or more polyacrylates.

27. The process according to claim 20 , wherein the calcium carbonate product consists essentially of (i) calcium carbonate, and (ii) ammonium zirconium carbonate, potassium zirconium carbonate, or mixtures thereof.

28. The process according to claim 20 , wherein the calcium carbonate product consists essentially of (i) calcium carbonate, (ii) ammonium zirconium carbonate, potassium zirconium carbonate, or mixtures thereof, (iii) one or more phosphate-free additives.

29. The process according to claim 20 , wherein the calcium carbonate product consists essentially of (i) calcium carbonate, (ii) ammonium zirconium carbonate, potassium zirconium carbonate, or mixtures thereof, and (iii) one or more polyacrylates.