METHOD OF IMPROVEMENT OPACITY Russian patent published in 2014 - IPC C09C1/02 C01F11/18 D21H19/36 

FIELD: textiles, paper.

SUBSTANCE: invention can be used in the manufacture of paper, varnishes and paints. The method of preparing the aqueous suspension of particulate calcium carbonate comprises providing an aqueous suspension of particulate calcium carbonate comprising at least one dispersing agent, and providing at least one alkali metal carbonate and/or alkali metal acid carbonate, where the alkali metal ion is selected from potassium and/or sodium. The solid matter content in the said suspension is 65-80 wt % relative to the total weight of the aqueous suspension. The said aqueous suspension of particulate calcium carbonate is diluted with water. Before and/or during and/or after dilution with water, the said aqueous suspension of particulate calcium carbonate is brought into contact with the said at least one alkali metal carbonate and/or alkali metal acid carbonate. At that the suspension of dispersed calcium carbonate after the stage of contacting has the pH value from 7.5 to 12.

EFFECT: invention enables to increase the light scattering coefficient S and opacity of the coatings obtained from the suspension of calcium carbonate.

16 cl, 2 ex