Process for preparing a wet ground mineral material

A process for preparing a wet ground mineral material comprising the steps of:

• a) providing an aqueous suspension comprising a mineral material, wherein the aqueous suspension has a pH value of equal to or above 8.0;
• b) adding at least one hydroxide base to the aqueous suspension provided in step a);
• c) wet grinding the aqueous suspension during and/or after step b) to obtain an aqueous suspension comprising a wet ground mineral material,
• wherein the wet grinding is carried out in the presence of at least one dispersing agent,
• wherein the pH value of the aqueous suspension provided in step a) is increased in step b) to a value in the range of above 9.60 to 11.90,
• wherein the aqueous suspension obtained in step c) has a pH value which is at least 0.10 above the pH value of a comparative aqueous suspension which is obtained by the same process but without carrying out step b), and
• wherein the aqueous suspension obtained in step c) has a pH value of equal to or above 9.30.