Calcium Carbonate

Calcium carbonate is a prevalent substance that exists naturally in rocks, primarily in the forms of calcite and aragonite, with limestone being the most well-known source. It is obtained through mining or quarrying and is referred to as Ground Calcium Carbonate (GCC). Alternatively, calcium carbonate can be produced from calcium oxide. This involves adding water to create calcium hydroxide, followed by the passage of carbon dioxide through the solution to cause the precipitation of calcium carbonate. This resulting form is known as precipitated calcium carbonate (PCC).

Synonyms
Argonite, Calcite, Chalk, Lime, Limestone, Marble, Ground Calcium Carbonate, GCC, Precipitated Calcium Carbonate, PCC, E170
Chemical Formula
CaCO3
CAS Number
471-34-1

Characteristics

Molar Weight
100.086 g/mol
Melting Point
825 °C
Boiling Point
decomposes
Density
2.71 g/cm³ (Calcite), 2.83 g/cm³ (Aragonite)
Forms
Grey, Powder, White

Uses and Applications

Key applications

  • Baking
  • Adhesives and Sealants
  • Agricultural
  • Household industrial
  • Paint and Coatings
  • Rubber
  • Floor coverings
  • Filler
  • Metallurgy
  • Plastics and polymers
  • Food additive
  • Nutritional supplements
  • Water treatment
  • Oil and Gas
  • Pulp and paper
  • Automotive
  • Personal care
  • Animal feed

Calcium carbonate

Calcium carbonate is also known by its common name of carbonated lime and is a chemical compound of the elements calcium, carbon and oxygen, which is of great importance to industry.
Calcium carbonate is one of the most widespread compounds on earth. It is mainly found in limestone, chalk and marble in the form of the mineral calcite, which is one of the most common minerals in the earth's crust, accounting for around five per cent of its total.
In the animal world, calcium carbonate is found in the exoskeleton of crustaceans, corals, mussels, snails and protozoa. It has also been found in the plant world. Other modifications of calcium carbonate are the minerals aragonite (derived from the most important occurrence of the mineral in Aragon) and vaterite.
As the industry requires calcium carbonate that is as white as possible, only a few deposits are suitable for extraction, despite the large natural deposits. The largest consumer of calcium carbonate is the paper industry (mainly utilizing deposits in France, Italy, Germany, Norway and Austria), followed by the plastics industry and the building materials industry.
Natural calcium carbonate is referred to in the industry as GCC (ground calcium carbonate). Synthetic calcium carbonate is referred to as PCC (precipitated calcium carbonate).

Properties

Calcium carbonate is a white, crystalline and odourless solid that is practically insoluble in water, but dissolves well in acids with foaming and the development of carbon dioxide. The calcium salt of carbonic acid belongs to the carbonate group of substances. Calcium carbonate decomposes into calcium oxide and carbon dioxide from around 600 degrees Celsius.
Calcium carbonate occurs in several anhydrous and two hydrate modifications as well as other amorphous forms. The most important variants are calcite and aragonite.
Synthetic calcium carbonate (PCC) is mainly produced by precipitation with carbon dioxide.

Calcium carbonate in the paper industry

Calcium carbonate is mainly used in the paper industry as a filler and coating pigment. It helps to improve the quality, smoothness, opacity and brightness and therefore the printing properties ft he paper.

Calcium carbonate in the construction industry

In the construction industry, calcium carbonate is mainly used in the production of cement (calcium silicate, calcium aluminate) and quicklime. In the form of rock flour, calcium carbonate is also an important filler and is also relevant for the production of mortar, plaster and paint.
rubber balls of different sizes

Calcium carbonate in the plastics industry

Calcium carbonate is widely used in the plastics industry. ft he as a filler and reinforcing agent for many plastics such as polypropylene (PP), polyethylene (PE) and polyvinyl chloride (PVC). Ist use improves the mechanical properties such as stiffness, strength and impact resistance of plastics and at the same time reduces production costs. Calcium carbonate also facilitates the processing of plastics by improving the flow properties and mouldability ft he materials. Last but not least, it creates a more attractive appearance.

Calcium carbonate in agriculture

By liming soils with calcium carbonate, the agricultural industry improves the fertility of the soil and prevents acidification.
Calcium carbonate also plays a role in livestock farming. Here it serves as a source of calcium, which overst he animals' mineral requirements and promotes egg production in poultry, for example.

Calcium carbonate in the food industry

Calcium carbonate is authorised in the food industry under the name E 170 as a food additive without maximum quantity restrictions. Calcium carbonate is primarily used as a colouring agent, but also serves as a calcium additive, filler, acidity regulator or anti-caking agent for products such as table salt, spices and baking mixes.

Other uses of calcium carbonate

Calcium carbonate is used by the pharmaceutical industry in medicines to regulate stomach acidity and as a dietary supplement to treat calcium deficiency and osteoporosis, among other things.
In the oil and gas industry, calcium carbonate is added to drilling fluids to control the density of the mud and stabilise boreholes. It helps to regulate pressure and prevent the uncontrolled inflow of fluids. It is also used to seal pores and cracks in rock formations, reducing the loss of drilling fluids during the drilling process.
In water treatment, calcium carbonate improves water quality and protects the infrastructure of water treatment systems. It is used to regulate the pH value of acidic water and thus prevents corrosion in pipes and systems. It is also used to soften water.
The cosmetics industry uses calcium carbonate as an abrasive in toothpastes and as a thickening agent in creams and lotions. In make-up products such as powder and foundation, it acts as a cost-effective filler.
In the cleaning industry, calcium carbonate is used as an abrasive in products such as scouring agents and powders. It is also used as a low-cost filler in soaps, detergents and other cleaning agents.
In the mining industry, calcium carbonate is used as a filler in borehole filling to increase the volume of boreholes and ensure their stability. As a flotation agent, calcium carbonate helps to separate certain minerals from others by influencing the surface properties of the particles.
In metallurgy, calcium carbonate is mainly used as a fluxing and cleaning agent: In steel production, it is used as a flux to bind and remove impurities such as slag and oxides. As a cleaning agent, calcium carbonate is used to remove impurities and slag from metal surfaces before they are further processed or refined.
In the rubber and caoutchouc industry, calcium carbonate is mainly used as a filler, which increases the volume of the end product and thus reduces production costs. It also improves the processing properties of the rubber and gives it additional strength and rigidity.
In the adhesives, sealants and lubricants industries, the use of calcium carbonate as a filler not only improves consistency and processability, but also saves costs. As a thickening agent, the substance controls the viscosity of adhesive and sealant mixtures.
Calcium carbonate is of great importance to the chemical industry as a starting material for the production of calcium compounds such as calcium oxide (burnt lime) and calcium hydroxide (slaked lime). It is also used as an acid-base reactant, for example to neutralise acids or as a pH regulator.