METHOD OF PREPARING CALCIUM CARBONATE-BASE FILLER Russian patent published in 2001 - IPC

FIELD: preparation of finely dispersed chalk from high-moisture chalks as filler in chemical, rubber-processing, paint and varnish, paper and cosmetic industries. SUBSTANCE: method comprises crushing natural calcium carbonate, drying thereof at 115-130 C. Prior to drying, crushed calcium carbonate containing 35-41% of moisture is converted into stable viscous plastic pulp-like state adding dispersant in amount of not greater than 0.15% of pulp weight, and the final pulp is thereafter milled in closed cycle to attain fraction with particle size of greater than 45 mcm of not higher than 1%, and dried. If moisture content in crushed calcium carbonate is lower then claimed limits, the moisture content is adjusted to said limits by adding water to calcium carbonate as pulp is prepared. Yield of product with fraction having particle size of smaller then 10 mcm is increased to 95.6-99.4%. EFFECT: more efficient preparation method. 2 cl, 1 dwg, 1 tbl