A complete chemical route from limestone to high-purity precipitated calcium carbonate — producing nano, ultra-fine, and coated grades that command premium value across paper, plastics, paint, and pharmaceutical industries.
Overview
Precipitated calcium carbonate (PCC) is a high-purity, chemically engineered CaCO₃ with controlled particle size and crystal shape — far more valuable than ground limestone for advanced industrial fillers.
Natural limestone is mostly calcium carbonate, but grinding it (GCC) yields irregular, coarse particles of variable purity. PCC takes a different route: limestone is calcined into quicklime, hydrated into slaked-lime milk, and then reacted with carbon-dioxide gas to precipitate pure calcium-carbonate crystals. Because the crystals form under controlled temperature, concentration, and additives, their size, shape, and surface can be engineered to the customer's specification.
The result is a family of premium functional fillers: nano-PCC (20-100 nm) for high-end sealants and plastics, ultra-fine PCC (1-3 μm) for paper and paint, and coated PCC (surface-treated with stearic acid or titanate) for hydrophobic polymer systems. PCC typically commands 3-10× the price of GCC, making a PCC plant a high-value downstream investment for any operator with access to quality limestone.
LIMING Machinery delivers complete PCC plants covering the full chemical route — from limestone calcination and CO₂ recovery through hydration, carbonation, drying, classification, and optional surface coating. Product purity reaches up to 98% CaCO₃, with particle size tightly controlled from 20 nm up to 3 μm.
Production Process
Five chemical stages convert limestone into engineered calcium-carbonate crystals with tightly controlled properties.
Equipment
Six equipment groups carry limestone through the chemical route to finished, packaged PCC.
Vertical shaft or rotary kiln that calcines limestone into quicklime, with CO₂ recovery for carbonation.
Slakes quicklime into milk-of-lime slurry and refines it to the required purity.
Controlled reactor where CO₂ gas is bubbled through milk-of-lime to precipitate PCC crystals.
Dewaters the PCC slurry and dries the cake to the target moisture for milling.
Mills and classifies dried PCC to the precise particle-size distribution for each grade.
Optional surface-coating system plus silo storage and bag/bulk packing for dispatch.
Product Grades
One plant can produce three premium PCC families by adjusting carbonation conditions and finishing.
20-100 nm precipitated calcium carbonate with extreme fineness and high surface area for high-end applications.
1-3 μm PCC with controlled crystal shape (rhombohedral or scalenohedral) for paper, paint, and standard plastics.
Surface-treated (stearic / titanate) PCC with hydrophobic character for dispersion in non-polar polymer systems.
Applications
PCC's engineered particle size and purity make it a premium functional filler across four major industries.
Brightness, opacity filler and coating pigment.
Stiffening, anti-block, cost-reducing filler in PVC, PP, PE.
Extender pigment improving opacity and durability.
Calcium supplement, antacid, and tablet excipient.