The preparation of active calcium carbonate usually adopts two processes: one is to mix and grind, modify and grade the heavy and light calcium carbons of certain particle size and proportion; the other is to grind the heavy and light calcium carbons separately, and then grade and modify. These two processes are simple, with low equipment investment, and the output can be directly packaged after leaving the equipment, which is particularly suitable for the modification treatment of calcium carbonate by coupling agents. 

One end of the coupling agent molecule contains polar groups, which can undergo a chemical reaction with the hydroxyl groups on the surface of calcium carbonate to form stable chemical bonds; the non-polar group at the other end coats the surface of the calcium carbonate particles, making the surface hydrophobic and reducing the free energy of the particle surface, improving the compatibility with the resin, and endowing the composite material with better physical and mechanical properties. Currently, the coupling agents used for modifying calcium carbonate mainly include titanium acid ester coupling agents and aluminum acid ester coupling agents. 

The machines required for the coating modification and the mixed grinding of calcium carbonate are also very important. The honeycomb mill can be assembled with different materials according to the characteristics of calcium carbonate, and has the advantages of preserving the color and purity of calcium carbonate. Moreover, under normal conditions, multiple coating media can be applied simultaneously. It can simultaneously achieve grinding, drying, sorting, and surface chemical treatment of the powder, and can also dry and depolymerize the wet grinding filter cake and slurry. It is the ideal choice for active calcium carbonate. 

The main equipment of the honeycomb mill includes: ball mill, modification machine, depolymerization machine, shaping machine, dry grinding, powder surface modification machine, spheroidization machine, dryer, powder modification machine, surface modification machine, coating modification machine, mechanochemical modification, activation machine, disintegrator, dryer, surface coating, etc.