Kaltsiumkarbonaat

Calcium carbonate, known in Estonian as kaltsiumkarbonaat, with the chemical formula CaCO3, is a common inorganic compound. It occurs naturally in several mineral forms, most notably calcite and aragonite, which differ in crystal structure. A less common metastable form is vaterite. Calcium carbonate is a major component of sedimentary rocks such as limestone, chalk and marble, and makes up the shells and skeletons of many marine organisms.

In nature it forms in both inorganic sedimentary deposits and biogenic materials. Calcite is the dominant mineral in limestone and marble, while aragonite is commonly found in mollusk shells and some coral skeletons. The stability of the crystal form depends on environmental conditions such as temperature, pressure, and chemistry of the surrounding fluids.

Industrial production and forms: Limestone and marble are mined and processed to produce ground calcium carbonate (GCC) for use as filler and whitening agents in paper, plastics and paints. Precipitated calcium carbonate (PCC) is produced chemically to achieve controlled particle sizes and purity. Thermal decomposition of CaCO3 yields calcium oxide (quicklime) and carbon dioxide, a key step in cement and lime production.

Applications: Calcium carbonate is used in construction (cement, lime), as a filler and whitening agent in paper, plastics and paints, in toothpaste, and as a dietary supplement or antacid. It also serves in agriculture to neutralize acidic soils and supply calcium to crops.

Safety and environmental aspects: It is of low solubility in water but dissolves in acids, releasing carbon dioxide. Inhalation of dust can irritate the respiratory tract; proper handling is advised. Quarrying and processing can impact landscapes and ecosystems, and regulatory measures address emissions and waste.