PROCESS FOR OBTAINING PRECIPITATED CALCIUM CARBONATE Russian patent published in 2018 - IPC C01F11/18 C09C1/02 C08K3/26 B01D29/11 

FIELD: chemistry.

SUBSTANCE: invention can be used in the production of paper, ink, paints, plastics. Process for the preparation of a precipitated calcium carbonate product involves the preparation of an aqueous suspension of precipitated calcium carbonate seeds by carbonizing a suspension of Ca(OH)₂ in the presence of 0.005-0.030 mol of Sr in the form of Sr(OH)₂ per mole of Ca(OH)₂. Dewatering and dispersing the precipitated seeds of calcium carbonate are carried out to obtain an aqueous suspension of precipitated calcium carbonate seeds, of value d₅₀, less than or equal to 0.1-0.3 mcm, and a BET specific surface area of 10 to 30 m²/g. An aqueous suspension of precipitated calcium carbonate is formed by carbonizing a Ca(OH)₂ in the presence of 0.5-5% in the expression for the dry mass of precipitated seeds of calcium carbonate, obtained at the stage of dewatering and dispersion. Precipitated seeds of calcium carbonate have a value of d₅₀, which is less than d₅₀ precipitated calcium carbonate. These precipitated seeds have an aragonite polymorph content greater than or equal to that of the precipitated calcium carbonate product. In this case, the dewatering step is carried out using a tubular press.

EFFECT: invention makes it possible to increase the aragonite content in precipitated CaCO₃ to more than 60% by weight without the step of grinding the seeds of calcium carbonate.

13 cl, 2 dwg, 1 tbl, 3 ex