PROCESS FOR IMPROVING THE PARTICLE SIZE DISTRIBUTION OF A CALCIUM CARBONATE-CONTAINING MATERIAL Russian patent published in 2018 - IPC C09C1/02 C09C3/04 C01F11/18 C08K3/26 C04B14/28 D21H17/67 

FIELD: chemistry.

SUBSTANCE: invention can be used for producing paper and cardboard products, cosmetic, plastic products, sealing materials, paints, coatings. For the preparation of an aqueous suspension comprising at least one calcium carbonate-containing material, the process comprises providing a substantially dispersant-free aqueous suspension of calcium carbonate-containing material and pre-heating the suspension to a temperature of from 40 to 95 °C. Aqueous suspension is contacted before and/or during and/or after pre-heating step and/or before and/or during and/or after wet-grinding step, with a base for obtaining an aqueous suspension having a pH measured at 25 °C of > 9.0. Wet-grinding of the pre-heated suspension is performed at an initial temperature of 40–95 °C for obtaining an aqueous suspension of calcium carbonate-containing, having an average size value [d₈₀/d₂₀] of particles having an average particle size d₈₀ and particles, having an average particle size d₂₀ value is not more than 2.5. Maximum temperature achieved during wet-grinding is approximately 100 °C. Wet-grinding is carried out using a milling medium having a weight median particle size diameter d₅₀, which is from 0.1 to 2.5 mm.

EFFECT: invention allows to obtain narrow particle size distribution at low BET specific surface area, to reduce the amount of dispersing agents.

16 cl, 3 dwg, 8 tbl, 11 ex