Paper Calcite (Calcium Carbonate, CaCO3) is a high-purity mineral filler and coating pigment used extensively in the pulp and paper industry. In modern paper manufacturing, it has largely replaced kaolin clay because it provides superior brightness, opacity, and a smoother surface finish at a lower production cost.

1. Core Functions in Paper

• Filler (Internal Loading): Calcite is mixed directly into the pulp slurry. It fills the microscopic gaps between wood fibers, increasing the paper’s “bulk” and opacity while reducing the amount of expensive wood pulp required.

• Coating Pigment: Applied to the surface of the paper to create “Coated Fine Paper.” It provides a high-gloss, ink-receptive surface that is essential for high-resolution printing, such as in luxury magazines and high-end packaging.

• Acid-to-Alkaline Shift: The use of calcite allows for “Alkaline Papermaking.” This process produces “Acid-Free” paper that does not yellow or become brittle over time, which is critical for archival documents and high-end books.

2. Technical Specifications

For your SAP-managed industrial operations, paper-grade calcite is defined by two primary metrics:

• Brightness: Usually exceeding 90–95%, ensuring the paper looks “stark white” without the excessive use of optical brighteners.

• Particle Size Distribution (PSD): For coating, the calcite must be ground to sub-micron levels. This allows it to create a perfectly flat surface that reflects light uniformly, enhancing the “sparkle” or gloss of the paper.

3. Manufacturing Types

• GCC (Ground Calcium Carbonate): Produced by mechanically grinding high-purity white marble (like the Sparkling White from your Yatağan quarries). It is valued for its brightness and low cost.

• PCC (Precipitated Calcium Carbonate): Created through a chemical precipitation process. This allows for precise control over crystal shape and size, which is used for specialized “premium” paper products that require specific ink-absorption properties.