Calcium Carbonate & Dolomite

Omya controls raw material resources for marble, chalk, limestone and dolomite to make calcium carbonate fillers and coating pigments for use in numerous sectors of markets.

Calcium carbonate is an exceptional compound. The chemical formula CaCO3 stands for a raw material that exists everywhere in nature, dissolved in rivers and oceans, melted as “cold” carbonatite-lava and solidified as a mineral, dripstone or as parent material for whole mountain ranges.

Plants and animals need calcium carbonate to form their skeletons and shells, and even modern mankind could hardly imagine life without calcium carbonate. Almost every product of our day-to-day life contains calcium carbonate or comes into contact with it while being produced.

What is Calcium Carbonate?

Calcium carbonate accounts for more than 4% of the Earth’s crust. As a result, the three calcium carbonate minerals - calcite, aragonite and vaterite - are among the most important rock-forming minerals. And rocks are not the only calcium carbonate deposits in nature. Almost all stretches of water and countless plants and animals contain huge amounts of calcium carbonate as well. These natural resources are linked by the calcium carbonate cycle.

Plants and animals absorb calcium carbonate in water, where it exists in most cases dissolved in the form of calcium hydrogen carbonate Ca(HCO3)2, and use it to build up their skeletons and shells. After their death, mussels, coccoliths, algae and corals form sedimentary deposits on sea-beds. And the rock forming process is set in motion.

The first stage is the sedimentation process, from which chalk and limestone originate. Chalk is a poorly compacted sedimentary calcium carbonate rock, whose diagenesis is incomplete.

A completed sedimentation process results in the formation of limestone. If the sedimentation process takes place in magnesium containing water, a dolomitization may result. Part of the calcium ions in the crystal lattice are replaced by magnesium ions, leading to the formation of dolomite
CaMg(CO3)2.

Marble is a metamorphic rock resulting from the recrystallisation of limestone under high pressure and temperature. Whether chalk, limestone, dolomite or marble, all carbonate rock is subject to erosion. It dissolves under the influence of wind, temperature and water, and the cycle is ready to start anew.

The World of Calcium Carbonate

Calcium carbonate rock occurs throughout the world and is readily available. This explains why it has been among the most widely used raw materials for more than 5,000 years. The Ancient Egyptians built their pyramids out of limestone. However, the mining of industrial minerals is possible only in a few deposits world-wide. Extraction is only worthwhile if the purity, whiteness, thickness and homogeneity of the stone is appropriate, and even then intensive treatment is necessary to process top quality natural calcium carbonates (ground calcium carbonate (GCC)). Precipitated calcium carbonate (PCC) is a synthetic calcium carbonate, which in most cases is produced industrially by means of recarbonization.

Whether GCC or PCC, calcium carbonate has a wide range of applications.
There is a tailor-made product for each application in the paper, plastics, paint/coatings/adhesives industries as well as construction, environment, agriculture, food and pharma, where fineness and particle size distribution are optimally balanced for whatever the special purpose happens to be.

Ecology

Mining depends on the Earth’s resources. Omya takes great care of the environment and re-naturalizes old mines and quarries.