Calcium Carbonate

Calcium carbonate (CaCO3, CAS 471-34-1) is the worlds highest-volume mineral filler, supplied as ground calcium carbonate (GCC) produced by milling high-purity limestone, marble or chalk, or as precipitated calcium carbonate (PCC) synthesised by carbonation of lime for tighter particle-size control and higher brightness. It is used to reduce compound cost, raise stiffness and impact strength, improve dimensional stability and, in paper, to raise brightness and opacity. Buyers compare CaCO3 assay, whiteness, D50 and D97 particle size, oil absorption and whether the grade is surface treated with stearic acid for polyolefin compatibility.