A Certificate of Analysis (COA) is more than just a formality — it's a snapshot of your calcium carbonate’s quality. Understanding how to interpret each parameter on the COA helps you verify product consistency, avoid processing issues, and make informed sourcing decisions. Here's a quick, industry-friendly guide to reading a CaCO₃ COA.
Key Parameters on a CaCO₃ COA:
1. CaCO₃ Content (%)
- What it tells you: The purity of the material.
- Why it matters: Higher content (typically 94%–99.5%) means fewer impurities, better brightness, and enhanced performance across applications.
2. Whiteness (%)
- What it tells you: The visual brightness of the powder.
- Why it matters: Affects color output and final appearance. Ideal range: 95%–98% depending on the application (paint, plastics, etc.).
3. Moisture Content (%)
- What it tells you: The amount of water in the product.
- Why it matters: Low moisture (≤0.3%) ensures stable processing, especially in extrusion and compounding.
4. Particle Size (D50, D97)
- What it tells you: The average (D50) and maximum (D97) particle diameters.
- Why it matters: Impacts dispersion, surface area, and product texture. Choose finer sizes for films and coatings, coarser for ceramics and construction.
5. Oil Absorption (OA)
- What it tells you: The volume of oil required to wet the surface of CaCO₃ particles.
- Why it matters: Influences viscosity and processing behavior. Lower OA is better for plastics and rubber; higher OA can benefit paints.
6. pH Level
- What it tells you: Acidity or alkalinity of the material in suspension.
- Why it matters: A neutral pH (typically 8.5–9.5) ensures good compatibility with additives and resins.
7. Coating Type (if applicable)
- What it tells you: Whether the product is surface-modified, usually with stearic acid.
- Why it matters: Coated CaCO₃ improves dispersion and compatibility in polymers. Uncoated is preferred in water-based applications.
8. Brightness (optional)
- What it tells you: Reflective optical measurement (different from whiteness).
- Why it matters: Often used in paper and coatings to assess light reflectance. Higher brightness can boost opacity.
Conclusion:
A well-prepared COA is your first line of defense against inconsistent or low-grade CaCO₃. By understanding each parameter, you can evaluate offers more effectively, troubleshoot issues faster, and ensure the best fit for your product line.
Still unsure how to compare COAs from different suppliers?
Contact us — we’ll help you review the specs and choose the best CaCO₃ for your needs.
VIET NAM TECHNOLOGY MINERALS JSC – SHC GROUP
Ms. Jade Vu – International Sales Manager
WhatsApp: +84 90235 9898
Email: export6@shcgroup.vn
