Heavy Calcium Carbonate (GCC) is an inorganic mineral powder obtained by the mechanical crushing and fine grinding of natural limestone or marble.
Compared to light calcium carbonate (precipitated CaCO₃), it features higher density, larger particle size, and superior rigidity, making it ideal for use in plastics, paints, rubber, construction materials, and paper industries.

Chemical Structure

Heavy Calcium Carbonate is composed of calcium (Ca²⁺), carbon (C), and oxygen (O) ions, with the chemical formula CaCO₃.
It commonly occurs in calcite or aragonite crystal forms and is characterized by its high purity, thermal stability, and chemical inertness in most environments.

Property	Description
Chemical Formula	CaCO₃
Molecular Weight	100.09 g/mol
Crystal Forms	Calcite, Aragonite
Bond Type	Ionic
Chemical Classification	Inorganic Carbonate

Physical and Chemical Properties

Property	Typical Value / Description
Appearance	White or off-white powder, odorless
True Density	~2.71 g/cm³
Bulk Density	0.8–1.4 g/cm³ (depending on particle size)
Decomposition Point	~1339°C (decomposes to CaO + CO₂)
Solubility in Water	Very low (≈0.013 g/L at 25°C)
pH (suspension in water)	Slightly alkaline
Stability	Chemically stable, reacts with acids to release CO₂
Toxicity	Non-toxic, non-flammable

Main Industrial Applications

1. Plastics and Polymers
Used as a functional filler to improve stiffness, dimensional stability, and reduce production costs.

2. Paints and Coatings
Enhances whiteness, opacity, and surface durability, serving as an economical extender pigment.

3. Rubber Industry
Improves abrasion resistance, tensile strength, and processing performance.

4. Construction Materials
Essential raw material in cement, concrete, decorative coatings, and flooring compounds.

5. Paper Industry
Used as a coating and filler pigment, increasing brightness and printability.

6. Animal Feed
Acts as a source of calcium in feed formulations for poultry and livestock.

Advantages

Economical and widely available natural mineral.
Excellent thermal and chemical stability.
Non-toxic and environmentally safe.
Improves mechanical and optical properties in end products.
Versatile — suitable for diverse industries including plastics, coatings, and construction.

Limitations

Low solubility in water — unsuitable for some aqueous chemical processes.
Dust generation during handling requires effective ventilation and PPE.
Reacts with acids, releasing CO₂ gas; should not contact acidic materials.

Safety and Storage Guidelines

Safety: Non-toxic, but avoid inhalation of dust; use protective masks and goggles during handling.
Storage: Keep in a cool, dry place, away from acids and moisture.
Packaging: Supplied in multi-layer kraft bags, jumbo bags, or bulk silos.
Transportation: Handle according to standard industrial hygiene and chemical transport regulations.

Summary

Heavy Calcium Carbonate (GCC) is a cost-effective, high-performance filler and extender used in numerous industrial applications.
Its stability, whiteness, and mechanical reinforcement properties make it a preferred material in plastics, coatings, construction, and paper manufacturing worldwide.