Precipitated aragonite and a process for producing it

摘要

A process for producing a particulate precipitated aragonite calcium carbonate, comprises reacting an aqueous calcium hydroxide slurry with a carbon dioxide or a gas containing it, wherein the parameters of said process, including at least one preselected active agent, mode of operation, operating concentrations of raw materials, operating temperature, operating mixer speed and operating pH, are such that (A) the specific gravity of the product after drying for 12 hours at 120{C is <2.5 g/cm3; and (B) the specific gravity of this dry product after ignition for eight hours at 500{C is <2.5 g/cm3. The active agent may be carboxylic acid of the formula CH3(CH2)n COOH where n = 7-10 or a salt, anhydride ester or acyl halide thereof or a ketene CH3(CH2)n C=C=O (n=7-10).