Omya International Ag

Thomas Schlotterbach

Christian Jacquemet

Marc Maurer

Mathieu Skrzypczak

Robert Pirker

The present invention relates to a process for preparing amorphous calcium carbonate, the amorphous calcium carbonate obtainable by the process, its use as well as a product comprising the amorphous calcium carbonate and the use of a spray dryer for the preparation of amorphous calcium carbonate.

Production of amorphous calcium carbonate

The present invention provides a process for preparing a precipitated calcium carbonate product comprising the steps of: (a) preparing an aqueous suspension of precipitated calcium carbonate seeds by carbonating a suspension of Ca(OH)in the presence of 0.005 to 0.030 moles of Sr, in the form of Sr(OH), per mole of Ca(OH), (b) dewatering and dispersing the precipitated calcium carbonate seeds prepared in step (a) to obtain an aqueous suspension of precipitated calcium carbonate seeds having a dof less than or equal to 0.1 to 0.3 &#x3bc;m and a BET specific surface area of 10 to 30 m/g, and (c) forming an aqueous suspension of a precipitated calcium carbonate product by carbonating a slurry of Ca(OH)in the presence of 0.5 to 5% by dry weight of the precipitated calcium carbonate seeds obtained in step (b), wherein the precipitated calcium carbonate seeds have a dthat is less than the dof 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) characterized in that the dewatering of step (b) is carried out by the use of a tube press.

Growing community of inventors

Villach-St. Magdalen, Austria

Thomas Schlotterbach