METHOD OF PRODUCING CALCIUM CARBONATE Russian patent published in 1994 - IPC

FIELD: hydrometallurgy. SUBSTANCE: solution of ammonium carbonate is portionally fed into each reactor during precipitation calcium carbonate of calcium nitrate solution. Ammonium carbonate amount being fed into the first, the second and the third reactor is 40-60, 20-30 and 10-15 mass % respectively of total stoichiometry amount of calcium content in the solution. Total amount of ammonium carbonate being fed into cascade of reactors is 70-95% of its stoichiometry amount. Total period within which pulp stays in reactor cascade is not more than 60 min. Content of Sr impurities in thus prepared product is 0.15-0.22% . EFFECT: improves desired product quality, decreases strontium content in it. 2 cl, 2 tbl