Calcium Carbonate

Calcium carbonate (CaCO₃) begins decomposing to CaO and CO₂ at approximately 750–900°C. In a ceramic body, this decomposition must be complete before the body sinters and densifies, which is why controlled particle size and distribution are important for consistent firing behaviour.

CaO from calcium carbonate contributes to the glass former in the glaze system, reducing surface tension during melt and promoting glaze spreading and smoothness. It helps achieve a glossy, even glaze surface while contributing to chemical durability of the glaze.

High purity is essential — particularly low levels of iron (Fe₂O₃), manganese (MnO), and other colouring impurities — to avoid discolouration of the fired ceramic body or glaze. LIMESTONE POWDER POLYFIL is specifically controlled for purity, whiteness, and particle size for ceramic applications.

Yes. CaO formed from calcium carbonate influences the thermal expansion coefficient of the ceramic body by forming calcium silicate phases during firing. Careful control of the CaO content helps match the thermal expansion of the body and glaze, preventing crazing or peeling of the glaze layer.

Yes. Calcium carbonate is used in raw-material batch glaze formulations as a source of CaO flux. It improves glaze melt fluidity, gloss, and chemical durability, and is particularly important in matte and satin glaze development.