Colloidal calcium carbonate is a special type of precipitated calcium carbonate (PCC) with ultra-fine primary particles, narrow particle size distribution, good dispersibility and colloidal activity. It is widely adopted in rubber, high-grade paint, ink and sealant industries. Unlike ordinary GCC or common PCC, colloidal calcium carbonate has extremely strict limits on particle morphology, agglomeration degree, surface activity and impurity content. The core task of the mill is gentle de-agglomeration without destroying the original colloidal crystal structure, and matching the online surface modification function. Improper grinding will cause crystal crushing, poor dispersion and loss of colloidal properties.
1. Suitable Mill Types For Colloidal Calcium Carbonate
Air Classifying Mill (ACM Mill)
ACM mill is the mainstream option for medium-grade colloidal calcium carbonate.
- Fineness range: 1000 mesh to 3500 mesh
- Advantages: Integrated de-agglomeration and air classification. It can break soft agglomerates effectively with low impact intensity to retain the cubic or rhombohedral crystal shape of colloidal calcium carbonate. Surface modifier can be sprayed into the grinding chamber for in-situ coating treatment. Compact layout, stable operation and moderate investment cost. It is widely used for colloidal calcium carbonate applied in rubber and general industrial coatings.
- Limitations: For ultra-high-end colloidal products with ultra-narrow PSD, the classification precision needs to be upgraded. Raw material moisture must be strictly controlled below 0.5%.
Fluidized Bed Jet Mill
Fluidized bed jet mill is preferred for high-end colloidal calcium carbonate.
- Fineness range: 2000 mesh to 6000 mesh
- Advantages: No metal grinding medium collision. Particle dispersion relies on high-speed airflow shear, which minimizes crystal damage. Non-metallic lining can be equipped to avoid iron pollution and maintain high whiteness. It achieves excellent particle size uniformity. Perfect for high-end ink, silicone sealant and premium adhesive-grade colloidal calcium carbonate.
- Limitations: Higher energy consumption and initial investment. It is more suitable for high-value colloidal calcium carbonate rather than mass low-cost production.
Ultra-fine Ring Roller Mill
Ultra-fine ring roller mill is an alternative for modified colloidal calcium carbonate with medium output.
- Fineness range: 800 mesh to 2800 mesh
- Advantages: Adjustable grinding pressure to realize low-pressure gentle dispersion. Online modification system can be matched for continuous surface coating. Good cost performance for medium-capacity colloidal calcium carbonate lines for plastic filler.
- Limitations: Strict parameter tuning is required. Excessive roller pressure will crush colloidal primary particles and weaken colloidal activity.
Pin Mill
Pin mill is used for pre-dispersion of lightly agglomerated colloidal calcium carbonate.
- Fineness range: 600 mesh to 1500 mesh
- Advantages: Low shear force, simple structure and low investment. Usually used as pre-treatment equipment before the main grinding unit to loosen large agglomerates.
- Limitations: Cannot meet ultra-fine requirements alone; only works as auxiliary pre-dispersion equipment.
2. Core Selection Criteria For Colloidal Calcium Carbonate Mill
- Gentle De-Agglomeration, Not Crushing
Colloidal calcium carbonate already has qualified primary particles. The mill only needs to separate soft agglomerates. High-strength impact or extrusion will fracture primary crystals, reduce oil absorption and damage colloidal characteristics. - Surface Modification Compatibility
Most colloidal calcium carbonate requires surface coating treatment with stearic acid or other modifiers. The grinding system should reserve feeding ports for modifiers and guarantee uniform mixing during dispersion. - Impurity & Whiteness Control
Select wear-resistant non-ferrous liners to prevent iron contamination. Even tiny iron impurities will reduce whiteness and affect the colloidal stability of finished powder. - Moisture Control System
Colloidal calcium carbonate easily re-agglomerates under high moisture. A drying system should be equipped before feeding to keep raw material moisture within the specified range. Adhesion inside the grinding chamber must be avoided. - Particle Size Distribution Control
Colloidal products demand narrow PSD. The built-in classifier must have high precision to screen out coarse particles and ensure consistent product batch performance. - Closed Environmental Design
Adopt negative pressure closed loop system matched with pulse dust collector to prevent powder leakage and meet local dust and noise emission standards.
3. Final Recommendation
- Pre-dispersion step for colloidal calcium carbonate: Pin Mill
- Medium-output modified colloidal calcium carbonate for rubber and plastic: ACM Mill
- Medium-scale modified colloidal calcium carbonate with moderate fineness: Ultra-fine Ring Roller Mill
- High-end colloidal calcium carbonate for ink, sealant and high-grade coatings: Fluidized Bed Jet Mill
Before finalizing the equipment, raw material pilot tests are necessary to inspect de-agglomeration effect, crystal integrity, oil absorption value and particle size distribution. JACAN provides customized grinding and surface modification solutions for colloidal calcium carbonate production.
