Process for obtaining precipitated calcium carbonate

A material comprising the precipitated calcium carbonate product obtained in the process comprising the steps of:

• (a) preparing an aqueous suspension of precipitated calcium carbonate seeds by carbonating a suspension of Ca(OH)2 in the presence of 0.005 to 0.030 moles of Sr, in the form of Sr(OH)2, per mole of Ca(OH)2,
• (b) dewatering the precipitated calcium carbonate seeds prepared in step (a) in a tube press at a pressure in the range of 50 to 150 bar to obtain dewatered precipitated calcium carbonate seeds, and dispersing the dewatered precipitated calcium carbonate seeds so obtained in water to obtain an aqueous suspension of precipitated calcium carbonate seeds having a d50 of less than or equal to 0.1 to 0.3 μm and a BET specific surface area of 10 to 30 m2/g, and a pH of less than or equal to 9, wherein step (b) is conducted without grinding, and
• (c) forming an aqueous suspension of a precipitated calcium carbonate product by carbonating a slurry of Ca(OH)2 in the presence of 0.5 to 5% by dry weight of the aqueous suspension of precipitated calcium carbonate seeds obtained in step (b),
• wherein the precipitated calcium carbonate seeds have a d50 that is less than the d50 of the precipitated calcium carbonate product and the precipitated calcium carbonate seeds have an aragonitic polymorph content greater than or equal to the precipitated calcium carbonate product obtained in step (c), and wherein the precipitated calcium carbonate product obtained in step (c) has a total strontium quantity of 0.2 to 15 mol/dry metric tonne.