What is Calcium Carbonate?

What is Calcium Carbonate Used For?

Calcium carbonate is a chemical compound made up of calcium, carbon and oxygen atoms. It's a common mineral found in rocks.

Calcium carbonate is the main ingredient in chalk, limestone, marble, eggshells, snail shells, the shells and skeletons of sea creatures and pearls.  

Calcite and aragonite are crystalline forms of calcium carbonate.

It forms in seawater when dissolved calcium ions combine with dissolved carbon dioxide.  The calcium carbonate is insoluble in water and precipitates out of the solution.

This process plays an important role in the formation of many geological features such as coral reefs and limestone. 

Calcium carbonate can also form when calcium ions which are found in hard water react with carbonate ions. This leads to the formation of limescale. Limescale is made up mostly of calcite.

Hard water contains high levels of dissolved minerals including calcium and magnesium. When heated the minerals gradually precipitate.  The deposit that forms is limescale.
 
Calcium carbonate is a very useful naturally occurring substance that has many industrial and commercial uses.

It's used in the production of paper, plastic, paint and many other products that we use every day.

Here's a few examples; 

It's used in the production of asphalt, cement, concrete and bricks. In agriculture it's used as a conditioner to neutralise the acid in soils.  It's also used as a calcium supplement in animal feed.

Calcium carbonate is used as a food additive particularly in baked goods and cereals.  Not only is it a source of calcium but it also improves texture.

It can be used as a dietary supplement and as an antacid to treat stomach acid.  It's used in paper production to improve quality and brightness.

In paints calcium carbonate improves whiteness, opacity and matting. Matting makes it look less glossy. 

In environmental applications calcium carbonate is used to increase alkaline in water.