Patent ID: 8647597

Claim:
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.