The object of this research is the process of natural sedimentary calcite modification. The main problems that are solved in this research are the choice of the most suitable low molecular weight modifier among potassium methylsiliconate, sodium methylsiliconate and polymethylhydride siloxane, as well as the selection of optimal grinding regimes for the raw mineral. It is found that during the mechanochemical activation in the presence of organosilicon modifiers, hydrophilicity coefficient of the surface of the sedimentary chalk is significantly reduced. The most effective modifier for the surface of sedimentary calcite is polymethylhydride siloxane. It is established that in the presence of modifiers, grinding and amorphization of carbonate raw materials are activated, which is confirmed by a decrease in the intensity of calcite reflections to 9 % in the case of the use of polymethylhydride siloxane and by 5–7 % in the case of methyl siliconates. It is shown that the modification of the sedimentary chalk surface leads to a decrease in the capacity of its adsorption layer by 20 % of the capacity of the processed material. The strength of the coagulation structure in the filler-film former system also decreases: the yield point of the system with untreated material is 20 % higher than this limit for the system where chalk is modified with polymethylhydride siloxane. Despite the advantages of the proposed technical improvement, it is likely that the use of traditional fatty acid-based materials will remain more attractive in continuous production. Since this method has advantages from the point of view of the absence of the need to change the existing composites formulations, and from the point of view of minimizing the cost price. Research results will be more interesting in those industries where improving the properties of the material plays a decisive role.