Patent ID: 8017679

Claim:
An aqueous suspension comprising mineral particles and a grinding aid agent in an amount ranging from 0.3% to 1.0% by dry weight with respect to the dry weight of the mineral particles, the grinding aid agent being capable of being used for assisting the grinding of a mineral filler in a process comprising: 1) preparing a mixture comprising a grinding substance and an aqueous suspension comprising the mineral filler and the grinding aid agent in an amount ranging from 0.3% to 1.0% by dry weight with respect to the dry weight of the mineral filler, 2) grinding the mixture, and 3) concentrating the ground aqueous suspension comprising the mineral filler and the grinding aid agent after the grinding, where the percent dry weight of the mineral filler and the grinding aid agent is less than 71% in the aqueous suspension comprising the mineral filler and the grinding aid agent after the grinding and before the concentrating, wherein the grinding aid agent is a polymer comprising at least one selected from the group consisting of a homopolymer of acrylic acid, a homopolymer of methacrylic acid, and a copolymer of one or more of acrylic acid and methacrylic acid with one or more of acrylic, vinyl and allyl monomers, where the polymer is neutralized so that a molar percentage of neutralization of the active acid sites of the polymer by means of a neutralization agent containing a calcium ion is between 15% and 40%, a molar percentage of neutralization of the active acid sites of the polymer by means of one or more monofunctional neutralization agents is between 7% and 70%, a molar percentage of neutralization of the active acid sites of the polymer by means of a neutralization agent containing at least one selected from the group consisting of a magnesium ion, a barium ion, a zinc ion, an aluminum ion and a difunctional amine is between 0% and 30%, and a molar percentage of non-neutralized active acid sites is between 15% and 78%; and a dry coating of the suspension has a light scattering coefficient S greater than 100 m 2 /kg for a dry coating weight of 20 g/m 2 .