The invention relates to the use of at least one polymer containing at least one monomer selected from acrylic acid or methacrylic acid or mixtures thereof and at least one monomer which is the maleic anhydride as a dispersing and/or grinding aid agent in a fabrication process of an aqueous dispersion and/or suspension of mineral materials, wherein the molar ratio r (acrylic acid and/or methacrylic acid:(maleic anhydride) is strictly confined to the range between 2:1 and 0.1:1. Another object of the invention consists in the aqueous dispersions and suspensions of mineral materials thus produced and the use thereof in the fabrication of plastics, paper and paintworks.