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Product Benefits
Technical Details

Huntite (magnesium calcium carbonate, Mg3Ca(CO3)4) is an ultrafine, lamellar mineral. Being sub-micron makes it suitable as an extender for TiO2. Huntite is available with a stearic acid surface treatment, changing its nature from hydrophilic to hydrophobic. Huntite can be characterised by:


  • A high brightness
  • Lamellar particle shape
  • Sub-micron particle size.


Basic properties

Property H5 H10 Unit
Moisture 0.6 [%]
pH 10 [-]
Hardness (Mohs) 2 – 3 [-]
Refractive index 1.61 – 1.64 [-]
Colour (D65/ 10°) L* 98 [-]
Ry 93 [-]
Density 2.7 [kg/ dm3]




Product overview

Product Grade D50



[g/ 100 g]

Surface treatment
Portafill H5 3 57
H5 F11.0 3 57 1% stearic acid
H5 F12.0 3 57 2% stearic acid
H5 F13.0 3 57 3% stearic acid
H10 3.5 50


Production location Portafill H 

Portafill H is the brand name for Sibelco’s huntite products.




  • TiO2 extension: being an ultrafine, lamellar particle, huntite can be used to open up TiO2 agglomerates and to keep them separated during the drying/curing process. That way, TiO2 is more effectively used, which means less is needed to maintain the same properties – achieving a cost reduction.
  • Rheology control: due to its lamellar shape and fairly high oil absorption compared to other mineral fillers, huntite has an impact on the rheology profile of the sealant and/or adhesive. When applying shear, the lamellar particles will align and provide a low viscosity. When shear is removed, the lamellar particles lose their orientation and cause the viscosity to increase above the level expected when the particles had a more regular shape.


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