Selection Criteria for Milling Media in Pigment Dispersion (Solvent-Based Paints)
Pigment Type
Recommended Milling Media
Reason
Black Pigments (e.g. Carbon Black, Jet Black)
Ceria-Stabilized Zirconium Oxide
High density aids in fast dispersion; suits viscous and tough pigment types
White Pigments (e.g. TiO₂, ZnO)
Alumina Ceramic (99.7%)
High purity prevents contamination; smooth surface maintains brightness
Organic Pigments (e.g. phthalocyanines)
Zirconium Silicate
Cost-effective; medium density suits softer pigment grinding
Inorganic Pigments (e.g. Iron Oxide, Chromium Oxide)
Ceria-Stabilized Zirconium Oxide or Alumina (92%)
Need durable media; prevents contamination; good for abrasive particles
Summary:
Choose based on: pigment hardness, contamination sensitivity, cost, and formulation viscosity.
Zirconium oxide: For hard, viscous, aggressive systems.
Alumina: For inert and purity-critical grinding (especially white).
Zirconium silicate: For general-purpose, budget-friendly applications.
Steatite Ceramic Balls
Steatite Ceramic Balls are magnesium silicate-based milling media with the following characteristics:
Properties of Steatite Ceramic Balls:
Density: ~2.6–2.9 g/cm³ (low to medium)
Hardness: Moderate (Mohs ~6–6.5)
Chemical Nature: Chemically inert but less pure than alumina
Wear Resistance: Lower than alumina and zirconia
Cost: Very economical
Surface Finish: Smooth, but not as hard or wear-resistant as alumina or zirconia
Comparison with Other Media:
Property
Steatite
Alumina (92–99.7%)
Zirconium Silicate
Zirconium Oxide (Ceria Stabilized)
Density
~2.7 g/cm³
3.6–3.9 g/cm³
≥4.4 g/cm³
≥6.2 g/cm³
Wear Resistance
Low
High
Medium
Very High
Cost
Low
Medium–High
Low–Medium
High
Best for
Low-energy milling, low-viscosity systems
Purity-demanding pigments
Organic pigments
Tough, abrasive pigments
Suitable Pigment Applications for Steatite:
Pigment Type
Suitability of Steatite
Black Pigments
❌ Not ideal (too soft for carbon black, poor dispersion energy)
White Pigments
⚠️ Possible but risk of contamination and lower grind quality
Organic Pigments
✅ Economical for soft organic pigments in low-viscosity systems
Inorganic Pigments
❌ Not suitable for hard/inorganic pigments (wear + poor grinding efficiency)
Conclusion:
Steatite ceramic balls are cost-effective for low-energy milling of soft organic pigments in low-viscosity solvent-based paints, but not recommended for high-performance, abrasive, or purity-critical pigment dispersions.
