Precipitated calcium carbonate with improved resistance to structural breakdown

A process for producing precipitated calcium carbonate comprising the steps of:

• a) providing a calcium oxide containing material,
• b) providing an aqueous solution,
• c) providing a gas comprising carbon dioxide,
• d) preparing a milk of lime comprising Ca(OH)2 by mixing the aqueous solution of step b) with the calcium oxide containing material of step a),
• e) carbonating the milk of lime obtained from step d) with the gas of step c) to form an aqueous suspension of precipitated calcium carbonate, wherein:
• the carbonation is carried out in the presence of a static gas bubble comminution unit that is located in the milk of lime and the gas of step c) is flushed around and/or through the static gas bubble comminution unit.