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Aluminium trihydrate (ATH)

Explore the benefits of Sibelco high-purity aluminium trihydrate (ATH, aluminium trihydroxide) in coatings, polymers, adhesives & sealants.


Aluminium trihydrate (ATH)

Aluminium trihydrate (ATH) is initially derived from bauxite ore, before being refined into a fine white powder.  

Aluminium trihydrate (also known as ATH and aluminium trihydroxide, chemical formula Al (OH)3) is initially derived from bauxite ore, before being refined into a fine white powder.

About the product

Sibelco ATH is characterised by: 

  • high purity 
  • high whiteness 
  • relatively low density (2.4g/cm3) compared to other mineral fillers (typically 2.7g/cm3)   
  • medium Mohs hardness of 3 
  • decomposition around 180oC, releasing water (making it an excellent halogen-free flame retardant)

Our range is available in four grades: 

  • Fine: products with a defined PSD, top cut, colour, oil absorption and BET - typically used in applications critical to surface defects, colour, impregnation or FR-performance, often replacing fine precipitated ATH-grades.  
  • Medium / Coarse: products with a defined PSD and relatively high bulk density- typically used in applications where ease of handling and cost are important.  
  • Low Viscosity: products optimised for low oil absorption values. Particle shape and PSD are optimised for maximum packing performance, enabling higher filler loading levels in different resin systems.  
  • Special: coarse E-grades with a steep particle size distribution, well controlled on top cut and demagnetised - especially suitable for encapsulation of electrical components.  


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