Calcium Carbonate

Calcium carbonate is a mineral substance with chemical formula CaCO3. This substance, which has various industrial applications, constitutes more than 4 percent of the crust of the earth and can be found in different parts of the planet.

Composition and Properties of Calcium Carbonate

Calcium carbonate is a mineral substance that appears in the form of a white powder. Calcium carbonate is naturally found as. non-toxic, odorless, tasteless and entirely harmless. Therefore it is widely used in pharmaceutical industry. This mineral is almost non-soluble in normal water but can be dissolved in carbonated water. Its most important minerals include aragonite, lime stone, marble and travertine.

Applications of Calcium Carbonate

An important property of calcium carbonate is that it can be employed as a filler. When added to liquids and solids, it increases their ductility and mechanical resistance and changes their specific weight (unit weight). This highly useful mineral has the ability to increase thermal resistance, change the density of the product and increase its quality. It also has low oil absorption, proper brightness, low rigidity and rapid distribution among its valuable properties. Due to its low price, it reduces the final cost of products.

Industries that use this mineral substance are as follows:

• Ceramic and Glaze Industry:

  Due to its invaluable characteristics, calcium carbonate plays a key role as a primary material in the manufacturing of ceramics and glaze. Moreover, the low price of this substance leads to a significant reduction in production costs. Calcium carbonate is also one of the sources for manufacturing calcium oxide, which is not only used as a flux agent for smelting inside the kiln, it also increases the firing resistance at very high temperatures and rises the chemical and mechanical resistance of the body of the ceramic. In the glaze industry, this substance reduces the melting point and the coefficient of thermal expansion to reinforce the glaze.

• Glass Industry:

  Filler materials used in glass industry should be devoid of any pollutants and contaminations and should have high chemical resistance. High purity and chemical resistance of calcium carbonate makes it a good candidate as a filler material for this industry. This substance can also be used as flux agent in smelting, as well as preservative and thickness corrector within the glass industry. These properties lead to an increase in the pressure resistance and firmness, while enhance the mechanical, physical and esthetic traits of the glass. In addition, the low price of this substance results in a considerable decline of the final cost of the product. Any impurity in primary materials can lead to lower quality and negative impacts in the manufactured glass. Therefore, pure calcium carbonate with very low metallic impurity should be used for this purpose.

• Oil and Gas Drilling Industry:

  Calcium carbonate plays a key role in the process of drilling oil and gas wells. As a filler substance, it is one of the most important and required substances in the composition of drilling fluid (mud). Due to its alkaline nature, it reduces the acidity of its surrounding and prevents the corrosion of the drilling chisel. The result is considerable savings in the costs of drilling.

  The process of drilling produces polluted and acidic water that can be significantly and irreversibly harmful to the nature. Considering the alkaline nature of calcium carbonate, using a suitable granulation of this mineral is fundamental in water purification and eliminating harmful and acidic substances during the drilling process.

• Steel and Iron Smelting Industry:

  Limestone is used as a flux agent and temperature regulator during the process of manufacturing steel. Calcium carbonate is a source of calcium oxide or quicklime, which is widely used in the formation of slag. It is also used as a separator and collector of waste material (phosphorus, aluminum, sulfur, silica) during the manufacturing steel.

  By reducing the phosphorus that exist in steel, quicklime prevents the deformation and breaking of steel during cold work. In addition, sulfur makes steel fragile and cracks it; by reducing the sulfur level, quicklime significantly decreases its negative impacts.

  Other advantages of this substance include its application in iron smelting factories for the purpose of absorbing toxic gases (HCI, SO2, HF) and controlling air pollution.

• Plastic and PVC Industries:

  Calcium carbonate is used as a filler in plastic industry. Coated calcium carbonate is used in manufacturing PVC products. It enhances the dispersion of particles and mechanical attributes of the product and increases its resistance against humidity. Using this substance as a filler in PVC cables and wires prevents them from catching fire.

• Rubber Industry:

  Calcium carbonate powder is employed in manufacturing rubber. It leads to reduced melting temperature within the furnace, enhanced texture of the surface of produced rubber and homogeneity of primary materials. Moreover, it increases the strength and firmness, thickness, and rigidity of rubber. It also improves the resistance facing abrasion, and therefore raises the lifetime of the product. Considering the low price of this substance, using it reduces significantly the costs of manufacturing rubber. By using coated calcium carbonate in the process of producing rubber, the depreciation and corrosion of rubber products declines and the resistance and quality of final products increases considerably.

• Paint Industry:

  Calcium carbonate gives paints and coatings a brightness and whiteness. Therefore, it is mainly used in producing white and light colored paints. It also reduces production costs due to its low price. The more this substance is soft, the better its coating quality. Coated calcium carbonate is used as filler in manufacturing oil paints. This enhances the covering quality of the paint while reduces production costs significantly.

• Cable Manufacturing Industry:

  In the past, cable covers were made from PVC plastic materials. In addition to being highly flammable, they produce toxic gases and smoke when in contact with fire. Calcium carbonate is a non-toxic and odorless substance. Therefore, in case of fire, it will not have any damaging impact on the environment and the cable covering will not decompose. Because of these qualities and its low price, this substance is used in manufacturing cable covers.

• Pharmaceutical Industry:

  High doses of calcium are vital for children and the elderly. However, it is often impossible to obtain the required dose from natural sources. In these cases, physicians recommend calcium supplements for patients, provided in form of calcium carbonate or calcium citrate.

• Food Industry:

  Calcium carbonate prevents its environment from becoming acidic, while stops the activity of microorganisms. Food grade calcium carbonate is used as an additive and preservative in chewing gums, chocolate, starch refining and flour. This substance is also used as a leavening agent in the food industry, and an anticaking agent in producing spices.

• Livestock and Bird Industry:

  Calcium carbonate comprises one of the main elements in the feeds of livestock including cows, sheep, camels, etc. Aside from its anti-acidic property, it is a main source of calcium for these animals. It fortifies the bone skeletons of these animals and increase their lactation at the same time. It also reinforces the immunity of these animals against diseases.

  Due to lack of required amount of calcium found in natural food for birds, calcium carbonate powder is used in bird foods. It strengthens the birds’ skeleton and increases the number and the quality of the eggs they lay.

• Paper Industry:

  The most important component in manufacturing paper is wood. However, using wood not only increases production costs, but also destroys the nature. Using calcium carbonate in the process of manufacturing paper significantly lowers the consumption of wood. Today, some industrial countries have entirely substituted wood by this mineral substance in the process of producing paper. The product is called “stone paper”.

  The application of calcium carbonate reduces production costs and helps the environment by lowering the consumption of wood in this process. It also leads to enhanced quality and properties of the paper, better ink absorption and increased resistance of the paper produced.

• Adhesives, Resin and Sealant Industry:

  Calcium carbonate is used as a cheap filler material in the manufacturing of adhesives, resin and sealants. In addition, this soft and insoluble substance serves to control and reduce contractions, keep the viscosity and increase the physical rigidity and tensile strength in the formulation of adhesives and sealants.

  The alkaline property of this substance makes it compatible for the production of most types of resins. Calcium carbonate that is used in the adhesives, resin and sealant industry should be highly transparent.

• Agriculture:

  Increased acidity of soil provides a suitable environment for the growth of plant pests. The use of pesticides not only leads to environmental damages. It also has negative impact on the fertility of soil and the growth of plants. Agricultural lime (Ag Lime) is commonly used to minimize the acidity of soil and its negative consequences. This substance fortifies the soil, provides the necessary calcium for plants, and enhances the quality of leaves and fruits. However, adding excessive amount of this substance to soil with ideal pH makes it calcareous and unsuitable for agriculture.

• Construction Industry:

  Limestone is used in the construction of many ancient and historic monuments and buildings. Today, due to weathering caused by acid rains, limestone is no more used on its own for building purposes. It is merely used as a raw primary substance for producing building materials like lime, cement, concrete, blocks and asphalt.

• Concrete and Asphalt Industry:

  Calcium carbonate has the ability to increase the density of concrete and enhance its compressive performance and strength. Moreover, due to its appearance and smooth surface it is used as a filler in cement and concrete. In some cases, substituting limestone with cement in concrete leads to a final product with architectural application and provides the possibility of manufacturing various colors of concrete. In the process of manufacturing asphalt, calcium carbonate acts as a filler and sand improver in order to enhance the strength of the mixture.

• Detergent Industry:

  Calcium carbonate serves as a base in the process of producing soap. This enhances the quantity and quality of the product. It also increases the cleaning capacity of soap. The low price of this mineral leads to significant savings in the final costs of production.

• Environment:

  Limestone is used for controlling the pH of wastewater and purification of industrial waste. Moreover, it is used for sedimentation of phosphate and nitrogen compounds from limestone. Other usages of this substance include absorbing toxic gases (HF, SO2, HCI) in iron smelting factories and controlling air pollution. It also serves to enhance the quality of potable water and reduce its hardness.