Calcium Carbonate (CaCO₃) is a naturally occurring mineral primarily derived from limestone, marble, or chalk.
It is one of the most versatile and widely used industrial fillers and extenders, valued for its high brightness, low oil absorption, chemical inertness, and cost-effectiveness.
Used across a variety of industries, Calcium Carbonate improves the mechanical properties, processing characteristics, and surface finish of end products. It is available in both natural (GCC) and synthetic (PCC) forms, each with distinct benefits and applications.
Key Characteristics
- Chemical Formula: CaCO₃
- Appearance: White powder
- Refractive Index: ~1.59
- pH: 8.5–9.5 (aqueous suspension)
- Solubility: Insoluble in water
- Brightness: Typically >96% (depending on grade)
Applications of Calcium Carbonate
Plastics & Polymers
- Acts as a functional filler to improve stiffness, dimensional stability, and impact resistance.
- Reduces raw material costs and improves surface finish.
- Enhances processability in PVC pipes, films, cables, injection molded parts, etc.
Paints & Coatings
- Serves as an extender pigment, improving opacity and gloss.
- Helps in reducing the amount of expensive titanium dioxide without compromising brightness.
- Enhances scrub resistance and rheology.
Construction Materials
- Used in ready-mix concrete, tiles, adhesives, and sealants.
- Provides strength and durability to building products.
- Improves workability and reduces shrinkage in formulations.
Paper & Packaging
- Improves the opacity, brightness, and smoothness of paper.
- Used as a coating pigment or filler to enhance printability.
- Reduces cost while maintaining high performance in packaging boards.
Other Applications
- Rubber compounding: acts as a reinforcing agent in tires, seals, and profiles.
- Agriculture: used in animal feed, soil pH balancing (agricultural lime).
- Pharmaceuticals: used as a calcium supplement and tablet filler.
Types / Grades of Calcium Carbonate
1. Ground Calcium Carbonate (GCC)
- Sourced from natural limestone or marble.
- Available in various particle sizes.
- Cost-effective filler with high brightness and low abrasiveness.
- Suitable for plastics, rubber, and paints.
2. Precipitated Calcium Carbonate (PCC)
- Synthetically produced via chemical reaction.
- Offers uniform particle size and very high purity.
- Used in high-end applications like glossy papers, pharmaceuticals, and cosmetics.
3. Coated Calcium Carbonate
- Surface treated (usually with stearic acid) to improve compatibility with polymers.
- Enhances dispersion, reduces agglomeration, and improves mechanical properties in plastic systems.
4. Uncoated Calcium Carbonate
- Used where maximum whiteness, brightness, and chemical purity are required.
- Common in paper and paint industries.
Packaging & Storage
- Available in 25 kg bags, 50 kg bags, jumbo (1 MT) bags, or bulk tanker delivery.
- Should be stored in dry conditions away from moisture and contaminants.
- Shelf life: Stable indefinitely if stored properly.