Driven by the rapid growth of the plastics, rubber, and cable filler markets in India, a leading local non-metallic mineral processing company urgently needed to expand its production capacity of activated calcium carbonate (PCC/GCC) through advanced calcium carbonate modification technologies.
The key challenges faced by the customer were:
- How to maintain a high throughput of 5 t/h
- While ensuring a stearic acid coating rate above 99%
- And effectively solving downstream application issues caused by agglomeration and uneven coating of ultrafine powders
Project Overview:
- Location: India (Gujarat Industrial Zone)
- Material: Ground Calcium Carbonate (GCC, d50: 2–10 μm)
- Surface Modifier: Stearic Acid
- Target Capacity: 5 tons/hour
- Core Equipment: EPIC Powder Three-Roller Coating Machine
Why Choose a Three-Roller Coating Machine?
After comparing high-speed mixers and vortex mill coating systems, the customer ultimately selected EPIC Powder’s continuous three-roller modification technology. The decision was based on its unique triangular coating principle, which offers clear advantages for large-capacity, high-uniformity surface treatment.
Three-Chamber Continuous Processing for Full-Coverage Coating
Unlike batch-type mixers, the three-roller coating machine features three modification chambers arranged in a triangular configuration. Driven by high-speed rotors, the material and atomized stearic acid pass sequentially through all three chambers.
This design ensures that even at a high throughput of 5 t/h, the material undergoes sufficient shearing, collision, and dispersion, achieving uniform and dead-zone-free coating.
Precise Temperature Control for Optimal Stearic Acid Melting
Temperature control is critical in stearic acid modification:
- If the temperature is too low, stearic acid does not fully melt.
- If the temperature is too high, discoloration or degradation of the mineral may occur.
The EPIC Powder system integrates multiple precision-controlled stages:
- Automatic Feeding: Raw calcium carbonate powder is conveyed via screw feeder into the classification and preheating unit.
- Additive Metering: Stearic acid is melted in a dosing tank and automatically pumped at a rate synchronized with the main material flow.
- Core Modification: The material enters the EPIC Powder three-roller coating machine. Inside the three modification chambers, particles are exposed to intense turbulence generated by high linear rotor speeds (up to 60 m/s), allowing stearic acid molecules to form strong chemical bonds with the particle surfaces.
- Post-Treatment Circulation: The calcium carbonate modification powder is collected by a cyclone system and combined with auxiliary classification to remove any minor agglomerates that may form.
Operating Results and Customer Feedback
After on-site operation at the Indian production facility, the system demonstrated excellent stability and performance:
| Parameter | Customer Requirement | Actual Performance |
|---|---|---|
| Throughput | 5.0 t/h | 5.2 t/h |
| Coating Rate | ≥ 98% | 99.2% |
| Oil Absorption | ≤ 18 g/100 g | 16.5 g/100 g |
| Activation Rate | ≥ 98% | 99.5% (fully floating in water test) |