Calcium carbonate
It is a white crystalline compound chemically symbolised by the formula CaCO₃, and is a basic component of rocks such as marble and limestone. It is a versatile natural material used in construction, paints, and paper, as well as in the pharmaceutical industry as an antacid and source of calcium.
Physical characteristics and specifications:
- A fine, white, odourless powder.
- May also appear as colourless, transparent crystals.
- Insoluble in water.
- Chemically stable under normal conditions.
Extraction, mining and processing of calcium carbonate for industry
We are known for our high quality in all stages of calcium carbonate production, starting with the extraction of ore from mines, then crushing and grinding it into fine granules of carefully studied sizes and specifications. The product is then marketed locally or exported to global markets, and can also be used directly in various industrial applications thanks to its purity and ideal physical properties.
Extraction phase
The extraction of calcium carbonate begins with the removal of the overburden, which may be clay, sand or rock. The removal method depends on the type of overburden: › If the overburden is clay, it is broken up using mechanical equipment. › If the overburden is sand, it is simply scraped away and collected. › If there are hard rocky layers, blasting is used to remove them. Limestone, the primary source of calcium carbonate, is extracted using the bench mining method, which allows gradual access to the ore in an organized and safe manner.
Crushing stage
The crushing stage begins with the extracted limestone being transported to the crusher, where it is broken into smaller pieces ranging in size from 75 mm to 25 mm. During this stage, the material is also dried using hot air inside the crusher. The resulting granules are then transported to conveyor elevators, which store them in huge silos designed for this purpose. From there, they are fed into the grinding and classification stage by conveyor belts in preparation for final processing.
Processing stage
The granules produced in the crushing stage are ground using specialized mills and then classified to remove impurities and accompanying sand. After classification, the powder is transferred to dedicated collection silos, where each size is separated individually. The material is then transferred to the laboratory to begin the final processing and production of calcium carbonate. Finally, the product is packaged according to the required packaging type, whether for local distribution or export.
Calcium carbonate – applications and uses
Calcium carbonate, especially limestone, has a close historical relationship with human civilization. The ancient Egyptians used it to build the pyramids, and it was also used in temples, statues and sculptures by the Greeks and Romans, especially in its transformed form: marble. It has also been used in interior and exterior construction since ancient times.
With the Industrial Revolution, the demand for limestone increased significantly, especially in the cement industry, where it is a basic raw material, as well as in the iron and steel industries. After World War II, as a result of the development of the petrochemical industry, the use of calcium carbonate expanded to include many areas, such as:
- A filler in the plastics and paint industries.
- An auxiliary agent in rubber processing.
- An additive in the paper industry.
- An ingredient in the medical, fertilizer and pesticide industries.
- An essential component in the glass industry.
As a result, calcium carbonate has become one of the most versatile and widely used raw materials in various industrial sectors.
High-purity calcium carbonate powder is used in the manufacture of crystal glass and optical lenses such as camera lenses, and in the manufacture of certain electrical components. It is also used in schools to make chalk, colours, wax crayons and plastic erasers.
In agriculture, calcium carbonate powder is used to neutralise soil alkalinity, added to poultry feed to strengthen eggshells, used in fish and shrimp farming, and used as a veterinary medicine for animals.
Calcium carbonate powder is widely used in the manufacture of rubber products, where it acts as an effective filler that contributes to:
Facilitating processing and manufacturing operations.
Reducing production costs thanks to its economical price compared to other materials.
The most prominent rubber products containing calcium carbonate are:
- Electrical wires
- Belts and straps
- Shoes
- Tyres
- Hoses
- Rubber glue
- Rubber paste
- Sponges
It also improves the properties of these products in terms of durability, stability and flexibility, making it an essential component in various rubber industries.
Calcium carbonate powder is widely used in the food and health industries due to its nutritional benefits and physical properties:
In the food industry:
It is added to some foods as a natural source of calcium, such as:
- Sausages
- Bread
- Chewing gum
- Juices
- Sweets
- Biscuit crumbs
- It is also used in medical foods as a supplement to treat calcium deficiency in the body.
In the pharmaceutical industry:
- It is used in the composition of a number of health products, such as:
- Antacid powders
- Calcium pills
- Toothpastes
Bone-supporting medications such as supplements used in cases of osteoporosis.
Calcium carbonate is highly pure, making it safe for use in food and medicine when manufactured according to medical and nutritional standards.
The glass industry is one of the most prominent applications of limestone, where calcium carbonate (or lime – calcium oxide after decomposition) is a key component in the composition of glass, which usually consists of:
- Silica (SiO₂): forms the basic structure of glass.
- Soda (Na₂CO₃): lowers the melting point of silica to facilitate formation.
- Lime (CaO): added to maintain the chemical stability of glass and enhances:
- The strength and durability of glass.
- Its resistance to breakage.
- Its chemical stability.
It is essential that the limestone used in this industry is very pure and contains the lowest possible percentage of iron oxides, as their presence negatively affects the clarity and colour of the resulting glass.
- It lowers the melting point of iron, facilitating its smelting and reduction.
- It reacts with impurities such as silica and alumina to form slag, which helps separate impurities from the metal.
- CaCO₃ decomposes into calcium oxide (CaO) and carbon dioxide (CO₂), where:
- CaO reacts with unwanted oxides to form slag.
- CO₂ in the reducing environment of the furnace is converted to CO (carbon monoxide), which acts as a strong reducing agent for iron oxides, leading to the extraction of metallic iron.
Calcium carbonate powder is widely used in the paper industry, not only to impart a bright white colour, but also to improve the quality of the paper by modifying its chemical properties. When added:
It converts the paper from acidic to neutral, which prolongs its life and prevents it from rotting, unlike acidic newsprint, which decomposes over time.
It contributes to increasing the smoothness of the surface, reducing ink absorption, and improving printing.
It reduces production costs compared to using other materials.
Examples of paper types that contain calcium carbonate:
- Drawing paper
- Wrapping paper
- Sculpture paper
- Advertising paper
And other specialized and long-lasting paper types.
Since ancient times, calcium carbonate powder and limestone have been used in construction, and they remain essential materials in this sector today. Their use has expanded to include many modern applications, such as:
- Artificial marble manufacturing
- Wall panels
- Floor tiles
- Stone tiles
This widespread use is due to their unique physical and chemical properties, which give the materials durability, hardness and a natural aesthetic touch, as well as being economical and widely available options.
Calcium carbonate powder is used in the paint industry as a primary filler, accounting for 30–40% of paint components, due to its effective role in improving the natural properties of the final product.
Calcium carbonate contributes to:
- Increasing the thermal resistance and thermal conductivity of the paint
- Controlling density and adjusting viscosity
- Preventing runoff and improving the paint's adhesion
- Reducing the absorption of paint by wooden surfaces
Thanks to its low price, it also contributes to reducing production costs. It also increases hardness when combined with pigment or adhesive particles, forming a cohesive and stable layer with high fluidity.
It is important that the particle size of the calcium carbonate powder used in the coating is less than 20 microns to ensure optimal performance and coating quality.
Calcium carbonate powder is widely used in the manufacture of many plastic products derived from the petroleum industry, where it plays an important role in improving the physical properties of the plastic product. When added, it helps to enhance the product's resistance to deformation, increases its stability and durability, giving it a smooth appearance and good texture, and protects it from slippage.
In addition, calcium carbonate facilitates the plastic manufacturing process by enhancing its fluidity and distribution during moulding. Its use also reduces production costs due to its low price compared to petroleum and other raw materials.
Some of the most prominent plastic products that contain calcium carbonate are:
- Sewer pipes
- Electrical wires
- Parts of electrical equipment and cars
- Children's toys
- Plastic bags and packaging films
- Tableware and food containers
- Chairs and sanitary products
- Decorative materials, glue, and others.
Calcium carbonate is an effective additive that enhances quality and reduces costs at the same time.
