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Product Description
Benefits & Application Details



Colemanite is a borate mineral with the chemical formula Ca2B6O11·5H2O and is the main ore for Boron production. 


Thermal decomposition at 330 °C, loosing its water of hydration according to the following reaction: 

Ca2B6O11·5H2O -> Ca2B6O11 + 5H2O

The  Ca2B6O11 char residue has better mechanical properties than MgO, the char residue coming from the thermal decompostion of hydromagnesite.


Further characterized by: 

  • Relatively low density of 2.42 g/cm3 compared to other mineral fillers, which are typically at 2.7 g/cm3
  • Medium Mohs Hardness of 4.0
  • Decomposition around 330°C, releasing water.


Basic properties

Property Value Unit
Hardness (Mohs) 4.0 [-]
Refractive index 1.61 [-]
Density 2.42 [kg/ dm3]

PORTAFLAME® CA, C grades are micronized halogen-free flame retardant (HFFR) fillers (based on Colemanite), used as an effective synergist for other flame retardant fillers, such as ATH and magnesium hydroxide. 

Setting PORTAFLAME® CA, C grades apart from other flame retardant minerals is that the flame-retarding mechanism of PORTAFLAME® CA, C is based mainly upon its high char forming and glazing/fluxing ability in combination with endothermic decomposition (heat-sink effect). In applications such as polyolefin-based Wire & Cable compounds, a significant reduction of the peak Rate of Heat Release, as measured by the oxygen depletion method, is achieved.

PORTAFLAME® CA, C grades are easy to process and are an economical alternative to other flame-retardant fillers.

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