FIELD: printing industry.
SUBSTANCE: to produce a precipitated calcium carbonate, a suspension of calcium hydroxide is made by mixing of quicklime with water in a reactor with a mixer or in a tank, then the produced suspension is filtered via a 100-mcm filter. The filtered suspension is sent into a reactor of stainless steel equipped with a mixer. Temperature from 10 to 70°C is set, afterwards the suspension is sent into a reactor or a tank for carbonisation, where a carbon-containing gas is bubbled through the suspension. The suspension is drained from the tank, when electric conductivity achieves the minimum level, and pH falls below 8. Coarse particles are removed at a 45-mcm filter. At the same time the carbonisation stage is carried out at speed of carbonising gas flow of below 30 litres per minute under normal conditions per kg of calcium hydroxide in process of deposition. Concentration of precipitated calcium carbonate is increased using a cationic, anionic or combined disperser under quite moderate or mild conditions, which do not cause considerable damage of aggregates/agglomerates, until concentration from 25 to 60% is achieved, preferably in the range from 35 to 50%, most preferably - from 39 to 40 wt % of hard substances.
EFFECT: invention makes it possible to produce porous stable agglomerates of precipitated calcium carbonate with size of 1-5 mcm.
22 cl, 5 dwg, 17 tbl, 9 ex
