METHOD OF PREPARING CHEMICALLY PRECIPITATED CALCIUM CARBONATE Russian patent published in 2004 - IPC

FIELD: inorganic compounds technology. SUBSTANCE: invention provides preparation of product having commercial value in mechanical rubber, cable, perfumery, cosmetic, and paper industries, which as well can be used in preparation of fillers. Clarified distiller liquid from soda production is fed into reactor provided with heating system and stirrer. Temperature is raised to 20-80^o and 0.02 to 0.05 wt % of organic additive, namely oxyethylenated mono- and dialkylphenols, is added, said additive having formula wherein R represents alkyl residue having 8-10 carbon atoms and n=7-12 (OP-7 or OP-10). Thereupon carbonate-bicarbonate solution, which is sodium bicarbonate production waste (filtration stage mother liquor), is added in 0.3-0.5% stoichiometric excess with respect to calcium chloride. Treatment proceeds for 20-30 min until pH 7.2-7.4 is attained. Resulting precipitate contains 0.002-0.006% chlorine, has whiteness 95-98% and bulk density 120-180 kg/m³. EFFECT: enabled utilization of soda production waste. 4 cl, 1 dwg, 1 tbl