Calcium carbonate
Mineralogy
Ground Calcium Carbonate
Natural calcium carbonate deposits are made up of the skeletal remains of marine organisms that have sedimented to the bottom of a shallow sea. Under the right conditions, these sediments build up
over time to form thick layers. Geological movements and metamorphic processes lead to a differentiation
in their crystallization, giving either:
- chalk, a soft rock often associated with siliceous impurities.
- limestone, which is harder, whiter and purer than chalk.
- marble, which is the hardest and purest form of calcium carbonate.
Precipitated Calcium Carbonate
Calcium carbonate can also be produced synthetically in the form of Precipitated Calcium Carbonate (PCC). The transformation process consists in decarbonating limestone to separate CaO and CO2, and then recombining these elements in a chemical reactor. The final product has the same chemical composition as GCC, but with different properties in terms of particle size distribution, particle shape, and even higher purity.
Physical properties
- High brightness
- Blocky particle shape
- High purity
- Thermal conductivity
- Insoluble in water
- Alkaline
Applications
In paints and coatings calcium carbonates are cost-effective multifunctional fillers that improve whiteness, opacity and matting. They make ideal replacement for titanium dioxide.
In adhesives and sealants, finely ground calcium carbonates can be used at high loadings where they improve rheological properties, improve whiteness and opacity and generate cost savings.
Used in plastics, calcium carbonate improves the quality of breathable films for diapers, hygiene, medical and roofing applications. They are excellent reinforcement agents maximising mechanical properties in PVC building profiles and flooring.
