Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks as the minerals calcite and is the main component of pearls and the shells of marine organisms, snails, and eggs. It is estimated that about 5% of the Earth's crust is a form of calcium carbonate.
Calcium carbonate powder has many applications in real life and in manufacturing due to its popularity and cheapness. Here are some applications of CaCO3 (also known as limestone powder, calcite powder).
1. Paper industry.
Calcium carbonate is largely employed in the pulp and paper industry. It can be used as a filter and pigment, making possible the production of a whiter, higher quality pigment than other minerals.
In the construction industry, calcium carbonate is used as a filler in concrete, increasing its durability and appearance and to purify metals for use in construction applications.
3. The manufacture of paints.
Calcite powder is often used as filler in the manufacture of paints.
- It provides greater covering strength with minimum dripping on the surfaces.
- It has high whiteness which avoids interference with the paint’s colour and contributes to their opacity.
- It is low in cost and further reduces cost of paint manufacture as its high whiteness decreases the requirement of the white pigment titanium dioxide.
- It is also used as an extender in paints.
- It is also very useful in powder coatings particularly due to its high dispersibility.
4. Plastics industry
Calcite is used as filler in the production of all major synthetic polymers that make plastic namely polypropylene, polyethylene, polyvinyl chloride, polystyrene, ethylene vinyl acetate. These polymers have various applications like in bags, pipes, automotive parts, furniture, containers etc.
Calcite powder is widely used in plastics due to the following benefits:
- Cost effectiveness: Being a low cost material that can be used in high proportions, it considerably reduces the cost of plastic manufacture.
- High whiteness: Calcite’s high whiteness and opacity make it an excellent agent for de-lustration of naturally transparent man-made fibers without the need for additional pigments like titanium oxide. This ensures that the plastic components exhibit high color intensities and whiteness.
- High chemical purity: Calcite is devoid of heavy metal contamination, which leads to aging of the polymers.
- High dispersibility: Its grains do not collect together. Rather, they get distributed homogeneously resulting in uniformity within the final mass.
- Low oil absorption: This ensures that minimum resin is absorbed by the filler and also ensures that viscosity of the mix is not affected.
- High impact resistance: Calcite’s hardness and strength offer significant resistance to the plastic components against mechanical impact.
- Excellent dimensional stability: Calcite’s low coefficient of thermal expansion ensures minimum changes in size upon temperature changes.
- Moisture absorption: The moisture absorption properties of calcite are useful in order to obtain high humidity retention, to improve the consistency and dryness of the final mass.
5. Another application of calcium carbonate is in fertilizers to provide calcium to plants and pH stabilization of the soil.
6. Calcium carbonate can also be an additive to food products for livestock animals and humans and as a supplement in vitamins.
7. In water and sewer treatment plants, calcium carbonate is employed in the removal of acidity and impurities.
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